Pyridinium-based cyclophanes and methods of use thereof

Abstract

The present disclosure provides for a compound and composition comprising thereof. Further provided herein is a glucose monitor, methods of monitoring glucose in a subject in need thereof, and methods of regulating glucose in a subject in need thereof.

Description

[0001]Attorney Docket No.11001-205WO1 PYRIDINIUM-BASED CYCLOPHANES AND METHODS OF USE THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to, and the benefit of, U.S. Provisional Application No. 63 / 622,355 filed on January 18, 2024, the disclosure of which is hereby expressly incorporated by reference herein in its entirety. STATEMENT OF GOVERNMENT SUPPORT This invention was made with government support under Grant No. CHE-2337419, awarded by the National Science Foundation. The government has certain rights in the invention. BACKGROUND Traditional designs of synthetic receptors often rely on rigid, pre-organized binding pockets, lacking the dynamic adaptability of natural induced-fit mechanisms. Designing synthetic receptors that mimic these natural processes has posed significant challenges. Integrating allosteric modulation into a well-defined receptor architecture remains a complex and seldom-explored task. There is a need to overcoming these challenges to successfully emulate the dynamic interplay of induced fit and allosteric mechanisms seen in nature to harness the full potential of synthetic receptors in mimicking and potentially enhancing biological functionalities. The products and methods disclosed herein address these and other needs. SUMMARY In accordance with the purposes of the disclosed materials and methods, as embodied and broadly described herein, the disclosed subject matter, in one aspect, relates to a compound, compositions comprising thereof, and methods of using thereof. Thus, in one example, provided herein is a compound having the following formula: , Attorney Docket No.11001-205WO1 , or any combination thereof; wherein n is 1 to 20; and R2is H, CH3, or thereof. In some examples, R1is . In further In a glucose monitor is provided, including a receiver, a transmitter, and a sensor, wherein the sensor comprises the compound disclosed herein. In one example, a method of monitoring glucose in a subject in need thereof including contacting the compound disclosed herein with a biological sample from the subject thereby resulting in a combination of the compound and the biological sample, and measuring a signal from the combination of the compound and the biological sample. In a further example, a method of regulating glucose in a subject in need thereof is provided, including monitoring glucose as disclosed herein, determining the appropriate amount of insulin required by the subject in view of the signal, and administering the appropriate amount of insulin to the subject. Additionally, method of monitoring glucose in a subject in need thereof is provided, including contacting the compound of claim 1 with a biological sample from the subject thereby resulting in a combination of the compound and the biological sample, and measuring a signal from the combination of the compound and the biological sample. Additional advantages will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the aspects described below. The advantages described below will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects described below. FIGS. 1A-1B show structural formula of synthetic lectin BPAT2+•2Cl– (FIG. 1A) and carbohydrates (FIG.1B) investigated. FIG. 2 shows Conventional (left) and dynamic approaches to synthesizing BPAT2+•2Cl–. Attorney Docket No.11001-205WO1 FIGS. 3A-3D show (FIG. 3A) X-Ray single crystal structure of BPAT2+•2Cl–. (solvent and counter anions are omitted for the sake of clarity). (FIG.3B) Calculated cavity volume of BPAT2+ and isosurfaces representing the steric hindrance between the anthracene protons d and methylene bridging protons c based on IGM analysis. Front view (FIG. 3C) and truncated top view (FIG. 3D) of a snapshot from MD simulations of the hydration of BPAT2+•2Cl– showing the hydrogen bonding of cavity water molecules. FIGS.4A-4D show (FIG.4A) 1H NMR (400 MHz, D2O) spectra of BPAT2+•2Cl– (17 μM) titrated with glucose. (FIG. 4B) Changes in the chemical shift of proton b caused by the addition of glucose. The red trace represents non-linear fitting using a 1:1 receptor- substrate binding model. (FIG. 4C) Calculated changes in mole fraction of BPAT2+ and glucose BPAT2+ in D2O as a function of the substrate-receptor mole ratio. (FIG.4D) ITC profile of BPAT2+•2Cl– (17 μΜ) for the binding of glucose. FIG. 5 shows 1H NMR (400 MHz, D2O) spectra of BPAT2+•2Cl– at increasing concentrations from 0.012 mM to 1.2 mM. FIG. 6 shows 1H NMR (400 MHz, D2O) spectra of BPAT2+•2Cl– (0.017mM) titrated with Cl–. FIGS.7A-7D show (FIG.7A) 1H NMR (400 MHz, D2O) spectra of BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) titrated with glucose. (FIG.7B) Changes in the chemical shift of proton b’ caused by the addition of glucose. The red trace represents non- linear fitting using a 1:1 receptor-substrate binding model. (FIG.7C) Calculated changes in mole fraction of BPAT2+ and glucose BPAT2+ in D2O as a function of the substrate receptor mole ratio. (FIG. 7D) ITC profile of BPAT2+•2Cl– (0.5 mΜ) in the presence of NaCl (20mM) for the binding of glucose. FIGS. 8A-8G show X-ray single crystal structure of glucose BPAT2+•2Cl–. Front view (FIG. 8A) and top truncated view (FIG. 8B) of glucose encapsulated in the binding cavity of BPAT2+•2Cl– with two chloride anions binding at the allosteric sites. (FIG. 8C) Indirect interaction between the 1-OH group of the glucose and the carbonyl group of the BPAT2+ through hydrogen bonding over two water molecules as a bridge. The coordination environment of two types of chlorides binding with glucose (FIG. 8D) and the allosteric binding site of macrocycle (FIG.8E). (FIG.8F) Intramolecular hydrogen bonding between BPAT2+•2Cl-. (FIG. 8G) Stacking of BPAT2+•2Cl– highlight the two pyridinium bridges being sandwiched by anthracene panels. Magenta dashes represent the hydrogen bonds. Attorney Docket No.11001-205WO1 FIGS. 9A-9F show DFT optimized structures and their corresponding binding energies of (FIG. 9A) glucose⊂ BPAT2+ and (FIG.9B) glucose ⊂ BPAT2+•2Cl–. (FIG. 9C) X-ray single crystal structure of glucose ⊂ BPAT2+•2Cl– and DFT-derived binding energies. Electrostatic potential maps of (FIG. 9D) glucose⊂ BPAT2+and (FIG. 9E) glucose⊂ BPAT2+•2Cl–. (FIG. 9F) An overlay of DFT optimized structure (blue) of glucose⊂BPAT2+•2Cl– with its x-ray single crystal structure (magenta). Magenta dashes represent the same type of hydrogen bonds between the optimized structure and the solid structure while the green dashed line represents the different types of hydrogen bonds. FIGS. 10-14 show (FIG. 10) Overlay of low-energy conformers of BPAT2+ identified by CREST program. (FIG. 11) The only low-energy conformational isomer identified by the CREST program in the presence of two anthracene panels sandwiching between each pyridinium unit. (FIG.12) CD-spectra of BPAT2+•2Cl– (10 μΜ) in H2O with increasing glucose concentrations. (FIG. 13) CD-spectra of BPAT2+•2Cl– (10 μΜ) in an aqueous solution of NaCl (20 mM) with increasing glucose concentration. FIG.14) Schematic illustration of the allosteric modulation in BPAT2+, disrupting the induced- fitting process for glucose binding. FIGS. 15-17 show (FIG. 15) CD spectra of BPAT2+•2Cl– (10 µM) in the presence of 15 mM L-glucose (Blue) and D-glucose in H2O. (FIG.16) CD spectra of BPAT2+•2Cl– (10 µM) and L-glucose (15 mM) in H2O titrated with D-glucose (0–30 mM). (FIG.17) CD- spectra of BPAT2+•2Cl– (10 µM) and L-glucose (50 mM) in 1×PBS buffer titrated with D- glucose (0–17 mM). FIG.18 shows Synthesis of BPAT2+•2Cl– by a high dilution method. FIG.19 shows Synthesis of tetralactam macrocycle 3 by a dynamic approach. FIG. 20 shows 1H NMR spectrum (400 MHz, CDCl3, 298 K) of the tetralactam macrocycle FIG. 21 shows 13C NMR spectrum (101 MHz, CDCl3, 298 K) of the tetralactam macrocycle FIG.22 shows 1H NMR spectrum (400 MHz, DMSO-d6, 298 K) of BPAT2+·2Cl-. FIG. 23 shows 13C NMR spectrum (101 MHz, DMSO-d6, 298 K) of compound BPAT2+·2Cl-. FIG. 24 shows 1H NMR spectrum (600 MHz, CDCl3, 298 K) of the imine macrocycle Attorney Docket No.11001-205WO1 FIG. 25 shows 1H-1H gCOSY NMR spectrum (400 MHz, D2O, 298 K) of compound BPAT2+•2Cl–. FIG.26 shows Partial 1H–1H gCOSY NMR spectrum (400 MHz, D2O, 298 K) of a mixture of glucose (50 mM) and BPAT2+•2Cl– (0.2 mM). FIG. 27 shows Partial 1H–1H ROESY NMR spectrum (400 MHz, D2O, 298 K) of a mixture of glucose (50 mM) and BPAT2+•2Cl– (0.2 mM). FIG.28 shows 1H–1H gCOSY NMR spectrum (400 MHz, D2O, 298 K) of a mixture of glucose (47 mM), NaCl (20 mM), and BPAT2+•2Cl– (0.5 mM). FIG.29 shows 1H–1H ROESY NMR spectrum (400 MHz, D2O, 298 K) of a mixture of glucose (47 mM), NaCl (20 mM), and BPAT2+•2Cl– (0.5 mM). FIG. 30 shows Variable temperature 1H NMR spectra (600 MHz, D2O) of BPAT2+•2Cl– (0.2 mM). * represents a trace amount of TBACl residue. FIGS. 31A-31D show DOSY NMR spectra (600 MHz, D2O) of BPAT2+•2Cl– at (FIG. 31A) 0.02 mM, (FIG. 31B) 0.2 mM and (FIG. 31C) 0.8 mM. The change of peak intensity from proton d (indicated by the red arrow) was used to determine the diffusion coefficient. (FIG.31D) Fitting of the peak intensity of proton d over the gradient strength. FIG. 32 shows Structures of receptor BPAT2+•2Cl– and different carbohydrate substrates FIG.33 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with Me- β-glucoside. FIGS. 34A-34B show (FIG. 34A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and Me-β-glucoside BPAT2+•2Cl– (red trace) over the host- guest mole ratio. (FIG. 345) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of Me-β- glucoside in D2O at 298 K. Red lines are the curve fitting using a 1:1 host- guest binding model FIG.35 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with Me-α-glucoside FIGS. 36A-36B show (FIG. 36A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and Me-α- glucoside BPAT2+•2Cl– (red trace) over the host- guest mole ratio. (FIG. 36B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of Me-α- Attorney Docket No.11001-205WO1 glucoside in D2O at 298 K. Red lines are the curve fitting using a 1:1 host- guest binding model. FIG. 37 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with mannose. FIGS. 38A-38B show (FIG. 38A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and mannose BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG. 38B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of mannose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG. 39 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with GluNAc. FIGS. 40A-40B show (FIG. 40A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and GluNAc BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG. 40B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of GluNAc in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.41 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with galactose. FIGS. 42A-42B show (FIG. 42A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and galactose BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG. 42B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of galactose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.43 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with psicose. FIGS. 44A-44B show (FIG. 44A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and psicose BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG. 44B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of psicose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.45 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with fructose. Attorney Docket No.11001-205WO1 FIGS. 46A-46B show (FIG. 46A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and fructose BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG.46B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of fructose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG. 47 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with maltose. FIGS. 48A-48B show (FIG. 48A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and maltose BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG.48B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of maltose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG. 49 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with cellobiose. FIGS. 50A-50B show (FIG. 50A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and cellobiose BPAT2+•2Cl– (red trace) over the host-guest mole ratio. (FIG. 50B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.017 mM) caused by the addition of cellobiose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.51 shows 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) in the presence of glucose (50 mM) titrated with NaCl FIG.52 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with Me-β-glucoside (50 mM in syringe) in H2O. The solid line represents the best non- linear fit of the data to a 1:1 binding model (Ka = 1470 ± 101 M-1, t1H = -7.12 ± 0.27 kcal / mol). FIG.53 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with Me-α- glucoside (100 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and t1H. FIG.54 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with GluNAc (50 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and t1H. Attorney Docket No.11001-205WO1 FIG.55 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with galactose (50 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and t1H. FIG.56 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with psicose (100 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 126 ± 15 M-1, t1H = -22 ± 1.4 kcal / mol). FIG.57 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with maltose (100 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 476 ± 40 M-1, t1H = -6.28 ± 0.31 kcal / mol). FIG.58 shows ITC profiles for the titration of BPAT2+•2Cl– (0.017 mM in the cell) with cellobiose (50 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 209 ± 29 M-1, t1H = -6.92 ± 0.59 kcal / mol). FIG.59 shows UV / Vis absorption spectrum of BPAT2+•2Cl– (2 mM) in water. FIGS. 60A-60D show UV / Vis absorption spectra (FIG. 60A and FIG. 60B) of BPAT2+•2Cl– (2 mM) titrated with D-glucose in water. UV / Vis absorption spectra (FIG. 60C and FIG.60D) of BPAT2+•2Cl– (2 mM) titrated with NaCl in water. FIGS. 61A-61D show Titration of BPAT2+•2Cl– with L-glucose followed by addition of D-glucose. (FIG. 61A) CD spectra of BPAT2+•2Cl– (10 mM) with increasing concentration of L-glucose (0–15 mM) in H2O. (FIG. 61B) CD spectra of BPAT2+•2Cl– (10 mM) in the presence of L-glucose (15 mM) with increasing concentration of D-Glucose (0–15 mM) in H2O (continued from titration a). (FIG. 61C) CD spectra of BPAT2+•2Cl– (10 mM) in the presence of L-glucose (15 mM) and D-glucose (15 mM) with an increasing concentration of D-glucose (15 mM–30 mM) (continued from titration b). (FIG. 61D) Change of CD signal at 260 nm from the corresponding CD titration experiment (a–c) of BPAT2+•2Cl– with L- and D-glucose in water. FIG. 62 shows Ellipsoid plot of BPAT2+•2Cl–. Anisotropic displacement parameters were drawn at a 50% probability level. FIGS. 63A-63F show Front (FIG. 63A) and top (FIG. 63B) view of 2acetone⊂BPAT2+•2Cl–. Front (FIG. 63C) and top (FIG. 63D) view of dimeric BPAT2+•2Cl– through [π•••π] stacking and [CH•••π] interactions. Front view (FIG. 63E) and top view packing of BPAT2+•2Cl– in crystal lattice FIG.64 shows Ellipsoid plot of glucose ⊂BPAT2+•2Cl–. Anisotropic displacement parameters were drawn at a 50% probability level Attorney Docket No.11001-205WO1 FIG. 65 shows A comparison of structural formula of BPAT2+•2Cl– and Davis macrocycle. FIGS.66A-66I show X-ray single crystal structures. Front view (FIG.66A) and top truncated view (FIG.66B) of glucose encapsulated in the binding cavity of BPAT2+•2Cl– with two chloride anions binding at the allosteric sites. (FIG. 66C) Indirect interaction between the 1-OH group of the glucose and the carbonyl group of the BPAT2+ through hydrogen bonding over two water molecules as a bridge. A truncated view (FIG. 66D) of the single crystal structure of glucose ⊂ BPAT2+ and the structural formula (FIG. 66E) indicating the detailed binding pattern. Overlapped map (FIG. 66F) of glucose and the anthracene panel in the complex of glucose⊂BPAT2+. A truncated view (FIG.66G) of the single crystal structure of glucose ⊂ David macrocycle and the structural formula (FIG.66H) indicating the detailed binding pattern. Overlapped map (FIG.66I) of glucose and the anthracene panel in the complex of glucose ⊂ Davis macrocycle. FIG.67 shows 1H NMR spectrum (400 MHz, D2O, 298 K) of BPAT2+·2Cl- (0.017 mM) in its free form. FIG. 68 shows 1H NMR spectrum (400 MHz, D2O, 298 K) of BPAT2+·2Cl- (0.8 mM) in its aggregated form. FIG. 69 shows Variable temperature 1H NMR spectra (600 MHz, D2O) of BPAT2+•2Cl– (0.2 mM). * represents a trace amount of TBACl residue. The solvent peaks HDO were calibrated using the formula δ(HDO) = 7.83 − T / 96.9, where the temperature is measured in Kelvins. FIG.70 shows Van’t Hoff plot of the aggregation process of BPAT2+•2Cl– at 308, 318, and 328 K. FIG. 71 shows Full 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with glucose. FIG.72 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with glucose showing the change of BPAT2+•2Cl– showing the change of chemical shifts of BPAT2+•2Cl–. FIG.73 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.017 mM) titrated with glucose showing the change of chemical shifts of glucose. FIG.74 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with glucose showing the change of chemical shift of BPAT2+•2Cl–. Attorney Docket No.11001-205WO1 FIG.75 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with glucose showing the change of chemical shift of glucose. FIGS. 76A-76B show (FIG. 76A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and glucose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.76B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of glucose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.77 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with Me-b-glucoside. FIGS. 78A-78B show (FIG. 78A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and Me-b-glucoside BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG. 78B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of Me-b-glucoside in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.79 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with Me-α-glucoside. FIGS. 80A-80B show (FIG. 80A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and Me-α-glucoside BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG. 80B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of Me-α-glucoside in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.81 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with mannose. FIGS. 82A-82B show (FIG. 82A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and mannose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.82B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of mannose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. Attorney Docket No.11001-205WO1 FIG.83 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with GluNAc. FIGS. 84A-84B show (FIG. 84A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and GluNAc BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.84B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of GluNAc in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.85 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with galactose. FIGS. 86A-86B show (FIG. 86A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and galactose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.86B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of galactose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.87 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with psicose. FIGS. 88A-88B show (FIG. 88A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and psicose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.88B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of psicose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.89 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with fructose. FIGS. 90A-90B show (FIG. 90A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and fructose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.90B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of fructose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. Attorney Docket No.11001-205WO1 FIG.91 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.5 mM) and NaCl (20 mM) titrated with maltose. FIGS. 92A-92B show (FIG. 92A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and maltose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.92B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of maltose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.93 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– – (0.5 mM) and NaCl (20 mM) titrated with cellobiose. FIGS. 94A-94B show (FIG. 94A) Calculated changes of mole fractions for BPAT2+•2Cl– (blue trace) and cellobiose BPAT2+•2Cl– (red trace) in the presence of NaCl (20 mM) over the guest-host mole ratio. (FIG.94B) Titration isotherm created by monitoring changes in the chemical shift of proton b for BPAT2+•2Cl– (0.5 mM) in the presence of NaCl (20 mM) caused by the addition of cellobiose in D2O at 298 K. Red lines are the curve fitting using a 1:1 host-guest binding model. FIG.95 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.2 mM) titrated with glucose. FIG.96 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of BPAT2+•2Cl– (0.2 mM) in the presence glucose (50 mM) titrated with NaCl, showing no aggregation of glucose BPAT2+•2Cl– in the presence of NaCl. FIG. 97 shows Change of 1H NMR spectra (400 MHz, D2O / CD3CN, 298 K) of BPAT2+•2Cl– (0.2 mM) with increasing percentage volume of CD3CN, showing the disruption of aggregation by decreasing the hydrophobic effect of the solvent. FIG. 98 shows Partial 1H NMR spectra (400 MHz, D2O, 298 K) of (a) BPAT2+•2Cl– (0.4 mM), (b) a mixture of BPAT2+•2Cl– (0.4 mM) and glucose (0.4 mM), (c) a mixture of BPAT2+•2Cl– (0.4 mM) and glucose (0.8 mM), and (d) glucose (0.8 mM). FIG. 99 shows Partial 1H NMR spectra (600 MHz, D2O, 298 K) of a mixture of BPAT2+•2Cl– (0.2 mM) and glucose (33 mM) monitored over 25 days. FIG. 100 shows Partial 1H NMR spectra (600 MHz, D2O, 298 K) of a mixture of BPAT2+•2Cl– (0.2 mM), NaCl (20 mM), and glucose (33 mM) monitored over 25 days. FIG. 101 shows Partial 1H NMR spectra (600 MHz, D2O, 298 K) of a mixture of BPAT2+•2Cl– (0.5 mM), NaCl (20 mM), and glucose (40 mM) monitored over 25 days. Attorney Docket No.11001-205WO1 FIG.102 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with glucose (200 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 76 ± 0.8 M-1, DH = -5.2 ± 0.04 kcal / mol). FIG.103 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with Me-b-glucoside (200 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 137 ± 3.4 M-1, DH = -2.3 ± 0.03 kcal / mol). FIG.104 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with Me-α-glucoside (300 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and DH FIG.105 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with mannose (400 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and DH. FIG.106 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with GluNAc (300 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and DH. FIG.107 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with galactose (300 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and DH. FIG.108 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with psicose (400 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 15 ± 1.4 M-1, DH = -7.1 ± 0.4 kcal / mol). FIG.109 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with fructose (400 mM in syringe) in H2O. Note: The heat formation is too small to reliably determine the Ka and DH. FIG.110 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with maltose (300 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 38 ± 2 M-1, DH = -6.3 ± 0.2 kcal / mol). FIG.111 shows ITC profiles for the titration of BPAT2+•2Cl– (0.5 mM with NaCl 20 mM in the cell) with cellobiose (240 mM in syringe) in H2O. The solid line represents Attorney Docket No.11001-205WO1 the best non-linear fit of the data to a 1:1 binding model (Ka = 23 ± 0.8 M-1, DH = -5.3 ± 0.1 kcal / mol). FIG.112 shows ITC profiles for the titration of BPAT2+•2Cl– (0.2 mM in the cell) with glucose (25 mM in syringe) in H2O. The solid line represents the best non-linear fit of the data to a 1:1 binding model (Ka = 783 ± 62 M-1, DH = -3.4 ± 0.2 kcal / mol). DETAILED DESCRIPTION The following description of the disclosure is provided as an enabling teaching of the disclosure in its best, currently known embodiments. Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. As can be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. Attorney Docket No.11001-205WO1 The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. It can be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein. Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure. Definitions As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.” As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a compound”, “a composition”, or “a disorder”, includes, but is not limited to, two or more such compounds, compositions, or disorders, and the like. It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It can be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the Attorney Docket No.11001-205WO1 other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it can be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed. When a range is expressed, a further aspect includes from the one particular value and / or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g., the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g., ‘about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1% to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range. As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors Attorney Docket No.11001-205WO1 known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that “about” and “at or about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise. As used herein, the term “substantially free,” when used in the context of a composition or component of a composition that is substantially absent, is intended to refer to an amount that is then about 1 % by weight or less, e.g., less than about 0.5 % by weight, less than about 0.1 % by weight, less than about 0.05 % by weight, or less than about 0.01 % by weight of the stated material, based on the total weight of the composition. The term “subject” preferably refers to a human in need of treatment with an anti- cancer agent or treatment for any purpose, and more preferably a human in need of such a treatment to treat cancer, or a precancerous condition or lesion. However, the term “subject” can also refer to non-human animals, preferably mammals such as dogs, cats, horses, cows, pigs, sheep and non-human primates, among others, that are in need of treatment with an anti- cancer agent or treatment. The term “carrier” means a compound, composition, substance, or structure that, when in combination with a compound or composition, aids or facilitates preparation, storage, administration, delivery, effectiveness, selectivity, or any other feature of the compound or composition for its intended use or purpose. For example, a carrier can be selected to minimize any degradation of the active ingredient and to minimize any adverse side effects in the subject. The development of synthetic receptors capable of binding glucose has significant implications for diabetes management, particularly in regulating blood glucose levels. These molecules are poised to advance the creation of continuous glucose monitors and insulin treatments that respond to glucose levels. However, glucose’s highly hydrophilic nature and its structural resemblance to other sugars and water clusters pose a unique challenge. Specifically, it is difficult to achieve high affinity and selective recognition of glucose in water. This has led to a scarcity of molecules that can bind glucose with both high affinity and selectivity, essential for effective response at physiological glucose concentrations. In this disclosure, a synthetic lectin distinguished by its uniquely flexible binding pocket is Attorney Docket No.11001-205WO1 introduced. This pocket dynamically adjusts to glucose’s functional group distribution via an induced-fit binding mechanism—a process where the receptor conformation changes to accommodate the glucose molecule. This adaptability grants the receptor an exceptional ability to bind glucose in an aqueous environment, evidenced by a measured binding affinity of 3001 M−1. This makes it one of the most effective synthetic glucose-binding lectins known. The potential applications of this lectin include its use in continuous glucose monitoring systems and in the engineering of insulin that can dynamically respond to blood glucose levels. Composition Compound Provided herein is a compound having the following formula: wherein n is 1 to 20; and R2 is H, CH3, or any combination thereof. In some examples, R1 is . In further Attorney Docket No.11001-205WO1 In specific examples, the anthracene rings in Formula I are replaced with In some examples, this compound is referred to as BPAT2+• 2Cl-. Compositions Also provided herein is a composition comprising the compound disclosed herein at a concentration of less than 25 µm (e.g., less than 24 µm, less than 23 µm, less than 22 µm, less than 21 µm, less than 20 µm, less than 19 µm, less than 18 µm, less than 17 µm, less than 16 µm, less than 15 µm, less than 14 µm, less than 13 µm, less than 12 µm, less than 11 µm, less than 10 µm, less than 9 µm, less than 8 µm, less than 7 µm, less than 6 µm, less than 5 µm, less than 4 µm, less than 3 µm, less than 2 µm, or less than 1 µm). In some examples, the compound is present in a free state when present in a concentration of less than 25 µm. Free state, as used herein, refers to a molecule that is not chemically bonded to other molecules and is stable enough to exist on its own. Further provided herein is a composition comprising the compound disclosed herein at a concentration of 25 µm or more (e.g., 26 µm or more, 27 µm or more, 28 µm or more, 28 µm or more, 29 µm or more, 30 µm or more, 31 µm or more, 32 µm or more, 33 µm or more, 34 µm or more, 35 µm or more, 36 µm or more, 37 µm or more, 38 µm or more, 39 µm or more, 40 µm or more, 41 µm or more, 42 µm or more, 42 µm or more, 43 µm or more, 44 µm or more, 45 µm or more, 46 µm or more, 47 µm or more, 48 µm or more, 49 µm or more, 50 µm or more; 55 µm or more, 60 µm or more, 65 µm or more, 70 µm or more, 75 µm or Attorney Docket No.11001-205WO1 more, 80 µm or more, 85 µm or more, 90 µm or more, 95 µm or more, or 100 µm or more). In some examples, the compound is present in an aggregated form when present in a concentration of 25 µm or more. Aggregated form, as used herein, refers to molecules that have collided and associate together and exhibit collective behavior. In some examples, the composition has a binding affinity to glucose of from 2800 to 3200 M-1. Binding affinity refers to the strength of the interaction between a molecule and its binding partner, also referred to in some cases as a ligand. Also provided herein is a composition comprising the compound disclosed herein and a sugar. In some examples, the sugar comprises glucose, methyl-β-glucoside, methyl-α- glucoside, mannose, galactose, psicose, fructose, cellobiose, GlcNAc, maltose, or any combination thereof. In further examples, the sugar is glucose. Adduct Further provided herein is an adduct comprising the compound disclosed herein and glucose bound thereto. In some examples, the compound is bound to glucose via covalent bonding, ionic bonding, electrostatic bonding, hydrogen bonding, or any combination thereof. Glucose Monitor Also provided herein is a glucose monitor wherein the monitor comprises a receiver, a transmitter, and a sensor, wherein the sensor comprises the compound disclosed herein. In some examples, the sensor comprises a filament coated with the compound disclosed herein. In further examples, the compound is at a concentration of less than 25 µm (e.g., less than 24 µm, less than 23 µm, less than 22 µm, less than 21 µm, less than 20 µm, less than 19 µm, less than 18 µm, less than 17 µm, less than 16 µm, less than 15 µm, less than 14 µm, less than 13 µm, less than 12 µm, less than 11 µm, less than 10 µm, less than 9 µm, less than 8 µm, less than 7 µm, less than 6 µm, less than 5 µm, less than 4 µm, less than 3 µm, less than 2 µm, or less than 1 µm). In specific examples, the compound is at a concentration of 25 µm or more (e.g., 26 µm or more, 27 µm or more, 28 µm or more, 28 µm or more, 29 µm or more, 30 µm or more, 31 µm or more, 32 µm or more, 33 µm or more, 34 µm or more, 35 µm or more, 36 µm or more, 37 µm or more, 38 µm or more, 39 µm or more, 40 µm or more, 41 µm or more, 42 µm or more, 42 µm or more, 43 µm or more, 44 µm or more, 45 µm or more, 46 µm or more, 47 µm or more, 48 µm or more, 49 µm or more, 50 µm or more; 55 µm or more, 60 µm or Attorney Docket No.11001-205WO1 more, 65 µm or more, 70 µm or more, 75 µm or more, 80 µm or more, 85 µm or more, 90 µm or more, 95 µm or more, or 100 µm or more). A glucose monitor is a device that measures the amount of glucose in a subject’s blood. In some embodiments, the glucose monitor is a continuous glucose monitor, which is a wearable device that is inserted under the skin to measure the glucose in interstitial fluid, for example, every few minutes. A glucose monitor comprises a receiver, transmitter, and a sensor. The receiver is the device that displays the glucose measurement data and includes, but is not limited to, a handheld receiver and a smartphone. The transmitter is attached to the sensor and sends the glucose measurement data from the sensor to the receiver. The sensor is a small device inserted under the skin to measure glucose levels. In some examples, the sensor comprises a filament, wherein the filament is coated with BPAT2+• 2Cl- , that detects glucose in the interstitial fluid. In some examples, an insulin pump is integrated with the glucose monitor. Insulin pump refers to a small, computerized device that delivers insulin to a subject. This can be achieved via steady measured and continues doses or via a surge dose, at direction of the subject, around mealtimes. The doses of insulin are delivered through a flexible plastic tube called a catheter. The catheter is inserted through the skin into the fatty tissue with the aid of a small needle and is then taped in place. The delivery of insulin via an insulin pump mimics the subject’s body’s normal release of insulin. In some examples, the insulin pump is integrated with a glucose monitor such that the insulin pump can change the amount of insulin administered to the subject in view of real time measurements of the subject’s glucose via the glucose monitor. A glucose monitor sensor, when placed on the abdomen of a subject, can be placed a few inches away from the belly button, on the side of the abdomen. This provides a flat area of the stomach for placement of the monitor. A glucose monitor sensor, when placed on the arm of a subject, is often placed on the back of the upper arm of the subject. This area provides a flat surface with enough fat tissue for the sensor to properly function and is also less likely to be bumped or disturbed during daily activities. Method Method of Monitoring Glucose Attorney Docket No.11001-205WO1 The present disclosure, in one aspect, provides for a method of monitoring glucose in a subject in need thereof comprising contacting the compound disclosed herein with a biological sample from the subject thereby resulting in a combination of the compound and the biological sample, and measuring a signal from the combination of the compound and the biological sample. In some examples, the signal is circular dichroism (CD). Circular dichroism, or circular dichroism spectroscopy, refers to an optical technique that measures the difference in absorption of lift and right-handed circularly polarized light by a molecule, and therefore can be used in the quantitative analysis of chiral molecules, such as glucose. In further examples, the subject has Type I diabetes, Type II diabetes, prediabetes, hypoglycemia, hyperglycemia, gestational diabetes, polycystic ovarian syndrome, insulin resistance, adrenal fatigue, or any combination thereof. In certain examples, the biological sample comprises blood, interstitial fluid, or any combination thereof. Interstitial fluid is a bodily fluid that surrounds cells and tissues, carrying nutrients and waste. It comes from substances that leak out of blood capillaries. In specific examples, the glucose monitor disclosed herein is used to contact the compound with the biological sample and to measure the signal from the combination of the compound and the biological sample. Method of Regulating Glucose Also provided herein is a method of regulating glucose in a subject in need thereof comprising monitoring glucose as disclosed herein, determining the appropriate amount of insulin required by the subject in view of the signal, and administering the appropriate amount of insulin to the subject. One unit of insulin, which comprises 0.0347 mg of insulin, decreases blood glucose in a subject by from 15 to 100 mg / dL, depending on the subject’s individual insulin sensitivities and other factors. In some examples, the subject has Type I diabetes, Type II diabetes, prediabetes, hypoglycemia, hyperglycemia, gestational diabetes, polycystic ovarian syndrome, insulin resistance, adrenal fatigue, or any combination thereof. In further examples, the appropriate amount of insulin is administered to the subject subcutaneously. Attorney Docket No.11001-205WO1 Subcutaneous administration refers to administration beneath the skin into the subcutis, the layer of skin below the dermis and epidermis. In further examples, the appropriate amount of insulin is administered via a needle and syringe or via an insulin pen. In certain examples, the appropriate amount of insulin is administered to the subject via an insulin pump. In specific examples, the insulin pump is integrated with the glucose monitor. In some examples, the appropriate amount of insulin is administered to the subject via an insulin inhaler. An insulin inhaler is a device that delivers insulin powder into the lungs of a subject to help control blood sugar levels. Also disclosed herein is a method of diagnosing diabetes in a subject in need thereof comprising administering the compound disclosed herein to detect glucose levels in the subject and determining whether the glucose level is greater than diagnostic diabetes glucose levels. A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims. By way of non-limiting illustration, examples of certain embodiments of the present disclosure are given below. EXAMPLES The following examples are set forth below to illustrate the methods and results according to the disclosed subject matter. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative methods and results. These examples are not intended to exclude equivalents and variations of the present invention, which are apparent to one skilled in the art. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. There are numerous variations and combinations of reaction conditions, e.g., component concentrations, temperatures, pressures, and other reaction ranges and conditions that can be used to optimize the product purity and yield Attorney Docket No.11001-205WO1 obtained from the described process. Only reasonable and routine experimentation will be required to optimize such process conditions. Example 1: Allosteric Modulation in Biomimetic Synthetic Lectin: Regulating Glucose Binding via Induced-Fit Dynamics Introduction Discussed herein is a synthetic lectin featuring a uniquely flexible binding pocket that dynamically adapts to the functional group distribution of glucose through an induced-fit binding mechanism. This structural adaptability enables the receptor to exhibit a remarkable binding affinity for glucose in water, measured at 3001 M−1, marking it as one of the most effective synthetic lectins for glucose binding to date. The comprehensive analyses, including1H NMR titrations, isothermal titration calorimetry, circular dichroism absorption spectroscopy, X-ray crystallography, DFT calculations, and molecular dynamic simulations, have revealed a novel mechanism of regulating glucose binding through allosteric modulation. This mechanism involves chloride ions binding at allosteric sites, triggering receptor aggregation. This aggregation, in turn, rigidifies the binding pocket, disrupts the induced-fit process, and lowers the binding affinity. Notably, the receptor demonstrates exceptional sensitivity as a glucose sensor in various aqueous solutions, including water and PBS buffer. The work highlights the synergistic interactions of hydrogen bonding, hydrophobic effects, and electrostatic interactions in binding hydrophilic substrates in aqueous environments. The findings also reveal that the incorporation of flexible hydrogen bonding elements within binding pockets can enhance substrate binding via the induced-fit mechanism. This principle will guide the design of hydrogen bonding receptors capable of molecular recognition of hydrophilic substrates in water. Overall, the results not only demonstrate the feasibility of mimicking the sophisticated adaptability of biological receptors in synthetic molecular structures but also lay the groundwork for developing advanced biomimetic receptors. Induced-fit and allosteric control are valuable to the sophisticated adaptability of bioreceptors, enhancing specificity and efficiency in biomolecular interactions. The induced- fit model allows enzymes and receptors to dynamically adapt their conformation upon substrate binding, while allosteric control regulates protein activity via effector molecules binding at non-active sites, useful for metabolic regulation and signal transduction. These mechanisms exemplify the complex control within biological systems, enabling precise biomolecular interactions. Attorney Docket No.11001-205WO1 The development of biomimetic synthetic receptors, emulating such complexity, promises transformative applications in drug discovery, biosensing, therapeutics and materials science.βHowever, designing synthetic receptors that mimic these natural processes poses significant challenges. Traditional designs of synthetic receptors often rely on rigid, pre-organized binding pockets, lacking the dynamic adaptability of natural induced-fit mechanisms. Integrating allosteric modulation, typically achieved through conformational or electrostatic changes, into a well-defined receptor architecture remains a complex and seldom-explored task. Overcoming these challenges to successfully emulate the dynamic interplay of induced fit and allosteric mechanisms seen in nature aided in harnessing the full potential of synthetic receptors in mimicking and potentially enhancing biological functionalities. In this context, the development of biomimetic synthetic lectins capable of binding carbohydrates in aqueous environments marks a significant advancement. These synthetic lectins hold potential for diverse applications, including biomedical diagnostics, imaging, and as inhibitors in viral infection treatments, as well as playing a pivotal role in disease therapy. These biomimetic receptors mimic the ability of natural lectins to bind carbohydrates in aqueous environments through noncovalent interactions, such as hydrogen bonding and hydrophobic effects. These synthetic lectins have not previously been investigated regarding the induced-fit dynamics and allosteric control of their binding affinities. Furthermore, the majority of prior receptors still suffer from tedious synthesis and low affinities for carbohydrate binding in water. Discussed herein is the development of a biomimetic synthetic lectin that not only effectively captures glucose in water but also demonstrates an induced-fit mechanism and allosteric binding sites, thus mimicking the sophisticated adaptability of bioreceptors. The synthetic lectin presented is characterized by a flexible cavity that can adapt its conformation to fit the distribution of functional groups on glucose. This induced-fit binding mechanism enables the macrocycle to exhibit a remarkable binding affinity (Ka = 3001 M−1), representing one of the highest affinities for glucose binding molecules in water reported for synthetic lectins. Meanwhile, the receptor demonstrated high selectivity over other structurally similar sugars. Furthermore, two allosteric binding sites have been incorporated into this synthetic lectin, capable of binding chlorides. The binding of these allosteric effectors triggers aggregation of the receptors, leading to a rigidification of the binding pocket. The change in structural dynamics results in a decreased affinity for glucose, showcasing the allosteric modulation of substrate binding. This synthetic lectin acts as a highly sensitive sensor for Attorney Docket No.11001-205WO1 glucose in aqueous solutions, including water and PBS buffer, underscoring its potential in biomedical applications. These results not only demonstrate the feasibility of mimicking the sophisticated adaptability of bioreceptors in synthetic molecular receptors but also pave the way for the development of advanced biomimetic receptors. Such receptors possess properties prevalent in biological systems, expanding the horizons of synthetic biology and molecular recognition. Results and Discussion Structural design A water-soluble durene-based tetralactam macrocycle was developed, demonstrating promising glucose-binding affinity (Ka = 845 M–1) in water. Aiming to further enhance this affinity, (Figure 1a) BPAT2+•2Cl–was designed, which features two parallel anthracene walls, forming a larger binding pocket that increases the contact surface with glucose. The noticeable structure feature of BPAT2+•2Cl–is that it has four convergent NH hydrogen bonds pointing toward the binding pocket as a result of steric hindrance between protons c and d. Additionally, the incorporation of two pyridinium bridges brings multiple benefits: Firstly, the para C–H bonds, polarized by the pyridinium units, act as effective C–H type hydrogen bond donors, pointing convergently towards the binding pocket. Secondly, the receptor’s association with the hydrophilic counterion Cl–ensures good water solubility. Lastly, the methyl group and ortho protons on the pyridinium ring potentially serve as an allosteric binding site, offering a pathway to modulate the binding affinity for substrates. This newly designed receptor will undergo investigation to assess its binding properties with a range of structurally similar carbohydrates (Figure 1b), a step that holds significant potential in the understanding and manipulation of carbohydrate interactions in aqueous environments. A precursor to the synthesis of BPAT2+•2Cl–is the tetralactam macrocycle 3. This macrocycle can be obtained (Figure 2) through a conventional approach under high dilution conditions, leading to a modest yield of 13%. While this method benefits from the low solubility of 3, facilitating purification by solvent washing, it suffers from low yield. Consequently, an alternative synthetic strategy was explored. A dynamic approach employing the condensation of anthracene methylene diamine 2 with a pyridine 3,5-bisaldehyde precursor 4 provides imine macrocycle 5 in an excellent 88% yield. This intermediate can be readily converted to the desired tetralactam 3 via a Pinnick oxidation with a satisfactory 59% yield. Subsequent alkylation of 3 with iodomethane, followed by ion exchange, furnishes the water-soluble BPAT2+•2Cl–in a good 61% yield. Attorney Docket No.11001-205WO1 X-ray single crystal structure of BPAT2+•2Cl–was obtained by slow evaporation of a solution of BPAT2+•2Cl–dissolved in a mixture of acetone and water over three weeks. In the solid state, BPAT2+•2Cl–adopts (Figure 3a) a unique binding pocket formed by two parallel anthracene panels separated by a distance of 7.3 Å. Steric hindrance between the methylene protons and anthracene rings forces all four NH residues to converge toward the pocket. The independent gradient model (IGM) analysis (Figure 3b) confirms the presence of this steric hindrance by showing isosurfaces that indicate repulsive interaction. Using a two spherical probes method, the volume of the binding pocket was calculated to be 138 ų, which is slightly larger than cucurbit[6]uril (119 ų) but smaller than cucurbit[7]uril (205 ų). To understand the interaction between BPAT2+•2Cl–and water, a 10 ns molecular dynamics simulation under NPT ensemble at 300 K was performed. The result (Figure 3c and 3d) shows the hydrated macrocycle accommodating an average of 8.7 water molecules within its binding pocket. The size-restricted binding pocket of BPAT2+•2Cl–compels some of these cavity water molecules to form [CH•••π] interactions with the anthracene panels instead of hydrogen bonding with other water molecules. Consequently, these cavity water molecules only form an average of 2.96 hydrogen bonds, significantly less than the 3.62 observed in bulk water. Upon release to the bulk, these poorly hydrogen-bonded cavity water molecules are expected to dissociate from [CH•••π] interactions and reform more hydrogen bonds with bulk water molecules, a favorable enthalpic change when guest molecules displace them from the binding pocket. NMR and ITC Titration The interaction between BPAT2+•2Cl–and glucose in water was investigated using1H NMR titration. A solution of BPAT2+•2Cl–(17 μM) in D2O was titrated with aliquots of glucose, and1H NMR spectra were recorded after each addition. Notably, the stacked spectra in Figure 4a reveal that only proton b in BPAT2+•2Cl–exhibited a downfield shift upon glucose binding, suggesting its role in the binding process. This observation, considering the inward orientation of proton b, strongly suggests glucose binding within the binding pocket through [C–H•••O] hydrogen bonding with the macrocycle. Furthermore, the downfield shift implies a stronger [C–H•••O] interaction between the macrocycle and glucose compared to cavity water. Nonlinear fitting of the proton b’s chemical shift changes against the guest / host ratio (Figures 4b and 4c) revealed a remarkable binding affinity of 3001 M–1. This result represents one of the highest reported affinities for synthetic lectins binding with glucose in water, a Attorney Docket No.11001-205WO1 testament to the effectiveness of the BPAT2+•2Cl–design. Additionally, BPAT2+•2Cl–exhibits a binding affinity for glucose that is 5.8 times greater than that of the frequently employed lectin, concanavalin A, which possesses a binding constant (Ka) of 520 M–1. Compared to the previous durene-based macrocycle, replacing the smaller durene panels with larger anthracene walls enhanced the affinity by a factor of 3.6. This significant improvement highlights the contribution of the extended π-system to the binding interaction. Furthermore, the cationic pyridinium units play a crucial role in the observed high affinity. A structurally similar anionic macrocycle with an isophthalamide linker only registered an affinity of 56 M–1, demonstrating the importance of the polarized C–H bonds provided by the pyridinium groups. These additional hydrogen bonding donors significantly enhance the complex stability, contributing to the exceptional binding affinity of BPAT2+•2Cl–. The exceptional affinity between BPAT2+•2Cl–and glucose was further corroborated by isothermal titration calorimetry (ITC) experiments (Figure 4d). The ITC data revealed strong exothermic peaks upon glucose binding, a clear indication of favorable enthalpic interactions. Nonlinear fitting of the binding isotherm using a 1:1 binding model yielded a binding constant of 2400 M–1, consistent with the1H NMR titration results. Notably, the binding process was characterized by a strong binding enthalpy of −11.8 kcal / mol, accompanied by a substantial entropy penalty of −7.2 kcal / mol. This enthalpy-driven binding suggests that the interaction is primarily governed by comprehensive hydrogen bonding between glucose and the macrocycle. The enthalpic contribution likely arises from two factors: stronger hydrogen bonds between glucose and the macrocycle compared to those involving cavity water, and the release of cavity water molecules that can subsequently form additional hydrogen bonds with bulk water. These energetically favorable interactions outweigh the entropic cost associated with restricted conformational and translational freedom of the macrocycle and glucose within the complex. The formation of a stable complex between glucose and BPAT2+•2Cl–was further solidified by two additional experiments. Rotating frame Overhauser enhancement spectroscopy (ROESY) provided spatial information, revealing a through-space correlation peak between protons a on the macrocycle and a C–H proton on glucose (Figure 27). This observation directly confirms the close proximity between the two molecules within the complex. High- resolution mass spectrometry (HRMS) provided further validation, with a peak at m / z 979.3444 matching the theoretical m / z of 979.3433 for the [BPAT2+•glucose•Cl–]+adduct (Figures 17 and 18) with a molecular formula of [C54H52ClN6O10]+. These findings demonstrate the stoichiometry and formation of the complex. Attorney Docket No.11001-205WO1 The exceptional selectivity of BPAT2+•2Cl–for glucose was rigorously examined (Table 3) through1H NMR titration experiments involving structurally analogous sugars, as depicted in Figure 1b. Notably, glucose exhibits the highest binding affinity of 3001 M–1, as detailed in Table 3. This pronounced preference underscores the vital role played by the unique arrangement of hydroxyl groups on the glucose ring, which aligns well with the binding pocket of BPAT2+•2Cl–. Methyl-β-glucoside, structurally analogous to glucose but differentiated by a methyl group at the C1 position, shows a diminished affinity of 1189 M–1. This variation implies that even subtle alterations in the sugar structure can profoundly influence binding affinity. Another example is methyl-α-glucoside, where the orientation of the C1 hydroxyl group is altered to an axial position, resulting in an almost negligible binding. This observation emphasizes the role of the equatorial positioning of hydroxyl groups for optimal interaction with the macrocycle. Exploring sugars beyond glucose, including mannose, galactose, and psicose, which do not possess an all-equatorial hydroxyl group arrangement, revealed significantly weaker binding affinities. This pattern agrees with the observation that the temple-shaped binding pocket of BPAT2+•2Cl–is intricately tailored to accommodate the equatorial hydroxyl configuration specific to glucose. Interestingly, even cellobiose, a disaccharide comprised of two β-glucose units, only demonstrates a moderate affinity of 731 M–1, suggesting that the binding pocket of BPAT2+•2Cl–is too small to accommodate larger sugar molecules. Similarly, maltose mirrors that of cellobiose, attributable to its glucose unit. Complementary insights were gained from isothermal titration calorimetry (ITC) experiments. However, the subtler heat changes associated with the binding of lower-affinity sugars rendered ITC less effective for precise quantification at low macrocycle concentrations. Collectively, these findings delineate the notable selectivity of BPAT2+•2Cl–for glucose. The precise complementarity between the hydroxyl groups of the sugar and the macrocycle’s binding pocket, coupled with the pronounced sensitivity to structural variations, highlights the sophisticated nature of this molecular recognition mechanism. Aggregation of BPAT2+•2Cl–The1H NMR spectra of BPAT2+•2Cl–exhibits (Figure 5) a concentration-dependent behavior. Below 25 µM, the macrocycle exists in its free state, characterized by a distinct set of peaks (red). As the concentration increases to 150 µM, new peaks (blue) gradually emerge in the upfield region, indicating the formation of aggregated states. Above 150 µM, over 90% Attorney Docket No.11001-205WO1 of the macrocycle adopts this aggregated form. The coexistence of both sets of peaks suggests a slow exchange between the free and aggregated states. To further probe this aggregation behavior, diffusion-ordered spectroscopy (DOSY) experiments were performed on three BPAT2+•2Cl–samples in D2O at varying concentrations (0.02, 0.2, and 0.8 mM). The lowest concentration (0.02 mM) displayed (Figure 31A-31D) a diffusion coefficient of 2.31 × 106cm2 / s, corresponding to a hydrodynamic radius of 1.07 nm for a spherical hydrated BPAT2+•2Cl–cluster. Notably, at 0.2 mM, the diffusion coefficient dropped to 1.13 × 106cm2 / s, translating to a significantly larger hydrodynamic radius of 2.17 nm. This doubling in hydrodynamic radius confirms the presence of aggregates, with a volume estimated to be eight times greater than the free state. This result suggests an average of eight BPAT2+•2Cl–macrocycles participating in each aggregate. The 0.8 mM sample revealed a similar diffusion coefficient (1.08 × 106cm2 / s) and hydrodynamic radius (2.27 nm) to the 0.2 mM sample. This result indicates that further concentration increase beyond 0.2 mM has no appreciable impact on the size and structure of the aggregated BPAT2+•2Cl–species. The aggregation behavior of BPAT2+•2Cl–exhibits a clear temperature dependency, as revealed by varied temperature (VT)1H NMR spectra (Figure 30) of a 0.2 mM BPAT2+•2Cl–sample in D2O. Below 25˚C, the sample predominantly exists in an aggregated state. In the temperature range of 25˚C to 65˚C, the aggregated BPAT2+•2Cl–progressively dissociates into its free form. Above 65˚C, the macrocycle is completely dissociated, indicating a full transition to the free state. This narrow transition temperature window suggests that the aggregation is primarily driven by enthalpic interactions, coupled with an entropic penalty. At elevated temperatures, the entropy penalty becomes dominant over the enthalpic contributions, leading to dissociation. Consequently, the aggregation mechanism cannot be simply attributed to the hydrophobic interactions of the anthracene panels, which would typically yield a favorable entropic effect. To investigate the driving forces governing the aggregation behavior, a chloride titration experiment was conducted using a 0.017 mM solution of BPAT2+•2Cl–in D2O. The gradual addition of Cl–ions instigated (Figure 6) the formation of a second set of peaks, mirroring the aggregation patterns observed at higher BPAT2+•2Cl–concentrations. This unexpected aggregation at such a low macrocycle concentration strongly suggests that electrostatic interactions between the positively charged BPAT2+and Cl–are the primary driving force to trigger the aggregation. The formation of ion pairs effectively neutralizes the charge of BPAT2+, leading to a decrease in its water solubility. This reduction in solubility, Attorney Docket No.11001-205WO1 when combined with the large hydrophobic surface of the anthracene segments, induces aggregation. The Cl–-triggered aggregation was independently verified by a UV-Vis titration experiment (Figure 60A-60D), where adding NaCl to a BPAT2+•2Cl–solution (2 μM) resulted in decreased and red-shifted absorption peaks. This behavior marks a distinct contrast from the previously studied durene-based macrocycle, which did not exhibit such behavior. Glucose Binding in Aggregated State of BPAT2+•2Cl–Glucose binding properties of BPAT2+•2Cl–in its aggregated state were examined. A titration experiment was conducted at a high concentration of BPAT2+•2Cl–(0.5 mM), supplemented with 20 mM NaCl to enhance the stability of the aggregate. the observations revealed (Figure 7a) that the glucose binding behavior in the aggregated state of BPAT2+•2Cl–is notably different from its behavior in the free state. Specifically, it was noted that the inward-facing protons b’ exhibited an upfield shift upon the addition of glucose. This shift suggests a decrease in hydrogen bonding strength with glucose compared to their interaction with cavity water. Simultaneously, one set of the anthracene proton e’ showed a downfield shift, and a methylene proton c’ split into two separate sets of peaks. Intriguingly, the other halves of the protons e’ and c’ remained unchanged. These results indicate that under the conditions of the titration experiment, the aggregated BPAT2+•2Cl–can bind to glucose without disrupting its aggregated structure. In further analysis, the change in chemical shift for proton b’ was fitted against the guest / host ratio using a 1:1 binding model, as illustrated in Figures 7b and 7c. This analysis yielded an affinity of 90 M–1. This finding was corroborated by ITC experiments, which indicated (Figure 7d) a binding affinity of 76 M–1. The binding isotherm from ITC also revealed a binding enthalpy of –5.2 kcal / mol, which is markedly weaker than the glucose binding observed in the free state of BPAT2+•2Cl–. These results lead us to conclude that in its aggregated state, BPAT2+is less effective in establishing optimal binding with glucose. Single crystals of glucose⊂ BPAT2+•2Cl–were successfully grown by slowly evaporating an aqueous solution containing glucose (50 mM), BPAT2+•2Cl–(0.5 mM), and NaCl (20 mM) over a period of three months. The high concentration of the macrocycle and NaCl during crystal growth suggests that the x-ray single crystal structure reflects the aggregated state of BPAT2+•2Cl–when binding a β-glucose substrate. In this structure (Figure 8a), each glucose molecule forms eight hydrogen bonds with the inward-facing CH and NH hydrogen bond donors of the macrocycle. Additionally, the glucose’s axial C–H bonds are sandwiched between two parallel anthracene panels spaced 7.9 Å apart, an optimal distance for Attorney Docket No.11001-205WO1 establishing multiple [C–H•••π] interactions. This spacing, which can extend from 7.3 Å to 7.9 Å, highlights the binding pocket’s flexibility in the receptor BPAT2+•2Cl–. Notably, the remains hydrated within the structure, engaging in hydrogen bonding with four external water molecules. The 2 and 3-hydroxyl groups of the glucose also interact with a chloride anion via hydrogen bonding. In total (Figures 8b and 70), each glucose substrate is involved in 14 hydrogen bonds, encompassing interactions with the macrocycle, chloride ions, and water molecules. An indirect interaction of the 1- hydroxyl group of glucose with a carbonyl group from the macrocycle (Figure 8c), mediated by two water bridges. This observation suggests a novel role for solvent water in receptor-substrate binding, facilitating indirect hydrogen bonding. Moreover, each macrocycle (Figure 8a) forms ion pairs with two Cl–anions. These ion pairs are characterized by [CH•••Cl–] hydrogen bonds between the protons of the methyl group and the ortho protons of the pyridinium units with the chloride anion, reinforced by electrostatic interactions. These chloride binding sites, located outside the binding pocket, appear to function as allosteric sites, modulating the macrocycle’s glucose binding strength. The same Cl–counter anion (Figure 8e) is also involved in interactions with two water molecules and two other macrocycles, connecting with their anthracene and methylene protons. These interactions corroborate the findings from the1H NMR spectra (Figure 5), where proton c’ and e’ display diastereotopic characteristics and splitting. These Cl–ions exhibit a coordination number of eight. A different type of Cl–interaction (Figure 8d) involves hydrogen bonding with glucose hydroxyl groups and three water molecules, resulting in a coordination number of five. Finally, the pyridinium units of each macrocycle (Figure 8f) are found to engage in donor-donor- acceptor (DDA) hydrogen bonding arrays, leading to the formation of 1D supramolecular polymers. These pyridinium units (Figure 8g) are sandwiched between two electron-rich anthracene panels from separate macrocycles, resulting in each macrocycle being flanked by four others. Computational Analysis To elucidate the mechanism behind the allosteric modulation of glucose binding, density functional theory (DFT) calculations were conducted at the BLYP-D3 / SVP level. X- ray single crystal structure of glucose ⊂ BPAT2+•2Cl–was used as the starting point, optimizing this structure within a polarizable continuum model in water. the calculations revealed (Figures 9a and 9b) that the binding energy is 0.9 kcal / mol higher for glucose ⊂ Attorney Docket No.11001-205WO1 BPAT2+•2Cl–with both allosteric sites occupied by Cl–anions compared to the free macrocycle in complex with glucose (glucose ⊂ BPAT2+). The electrostatic potential maps of BPAT2+(Figure 9d) and BPAT2+•2Cl–(Figure 9e) indicated that chloride binding at the allosteric sites neutralizes the macrocycle’s charge. This neutralization diminishes the pyridinium units’ ability to polarize the inward-facing C–H bonds, consequently weakening the hydrogen bonding strength. Moreover, the optimized structure of glucose ⊂ BPAT2+displayed a binding pattern to glucose slightly different from that observed in the solid state. In the optimized structure, one of the inward- facing C–H hydrogen bond donors is oriented towards the 4-hydroxyl group of glucose. In contrast, in the solid-state structure (Figure 9c), this C–H bond is oriented towards the 3-hydroxyl group. The variation in binding patterns results in a higher energy state by 3.1 kcal / mol (Figure 9b and 9c) when the C–H hydrogen bond donor targets the 3- hydroxyl group in the solid state. An overlay of the optimized structure of glucose ⊂ BPAT2+•2Cl–with its solid-state counterpart ([glucose ⊂ BPAT2+•2Cl–]n) clearly demonstrates (Figure 9f) differences in the orientation of the pyridinium units, which influence the direction of the hydrogen bond donors’ interaction with glucose. These results point to a combined effect of the macrocycle’s charge neutralization and the misorientation of the pyridinium panels in contributing to the lower affinity observed in aggregated BPAT2+•2Cl–compared to the free macrocycle. The DFT calculations indicate that the macrocycle, in its solid state, cannot achieve optimal binding with glucose. In its free state, BPAT2+has a flexible binding pocket due to the rocking motion of the pyridinium units (Figures 10a and 10e). This flexibility enables the macrocycle to adapt and bind glucose via an induced-fit mechanism, where the pyridinium units can reorient to accommodate the glucose’s functional group distribution. In contrast, in the aggregated state (Figure 10b), the pyridinium units are constrained by the stacked anthracene panels, resulting in a rigidified binding pocket. This rigidity prevents the reorientation of the hydrogen bonding sites, leading to suboptimal binding with glucose and a consequent reduction in affinity. To test this hypothesis, constrained conformational sampling of BPAT2+was employed using the Conformer-Rotamer Ensemble Sampling Tool (CREST) program, applying constraints to the anthracene panels while allowing the pyridinium units to move freely. This approach identified ten low-energy conformers. An overlay of these conformers (Figure 10a) demonstrated the structural flexibility of the pyridinium units, which can Attorney Docket No.11001-205WO1 oscillate without impacting the molecule’s overall low-energy state. To simulate the aggregated state, two anthracene panels were positioned adjacent to each pyridinium unit, akin to their arrangement in the solid-state structure. While the anthracene panels were fixed, the pyridinium units were left free to move. As anticipated, this restricted setup yielded only one conformer (Figure 10b), supporting the hypothesis that the anthracene panels immobilize the pyridinium units, preventing them from reorienting to optimally bind glucose. This hypothesis is further supported by the experimental data from circular dichroism (CD) absorption spectroscopy. When BPAT2+binds glucose in its free state, it induces (Figure 10c) strong CD absorption peaks between 220-270 nm. These pronounced CD signals imply that the non-chiral BPAT2+, in its free state, can adjust its conformation to bind chiral glucose, forming a well-defined chiral complex. In contrast, aggregated BPAT2+•2Cl–under identical conditions (Figure 10d) exhibits (Figure 10d) similar but significantly weaker CD signals. Notably, the strongest CD peak, occurring at 260 nm and associated with pyridinium absorption, is much less intense in the aggregated state than in the free state. This difference in peak intensity suggests that in its aggregated form, BPAT2+•2Cl–has a more rigid structure, making it less effective at forming the indued chiral complex. These results suggest that hydrogen bonding receptors with rigid molecular skeletons may not be able to establish optimal noncovalent interactions with substrates. Instead, the incorporation of flexible hydrogen bonding residues inside the binding pocket could facilitate substrate binding through an induced-fit mechanism. Due to the strong affinity of free BPAT2+for glucose, more than 80% of its binding cavity becomes (Figure 10c) saturated with glucose at concentrations above 2 mM. Consequently, within the physiological 4 to 15 mM range, further increases in glucose concentration result in little to no change in the CD signal. In contrast, the lower affinity of BPAT2+•2Cl–in its aggregated state leads (Figure 10d) to a consistent yet small variation in its induced CD signals within the 5–10 mM physiological glucose concentration range. This observation indicates that while the magnitude of change is relatively modest, BPAT2+•2Cl–in its aggregated state exhibits a measurable response to variations in physiological glucose concentrations. Glucose Sensing To demonstrate the potential of BPAT2+•2Cl–in glucose sensing, L- glucose was introduced as both an indicator and competitor(Figure 61A-61D). Notably, L-glucose induced a reverse cotton effect in the CD spectrum of the complex, as shown in Figure 11a. This Attorney Docket No.11001-205WO1 approach effectively addresses the saturation issue of free BPAT2+at physiological glucose concentrations. In an experiment, a mixture of BPAT2+•2Cl–(10 µM) and L-glucose (15 mM) in water produced a positive induced CD signal at 260 nm. The subsequent addition of D- glucose gradually displaced (Figure 11b) the L-glucose, reducing the CD signal to zero when an equal amount of D-glucose (15 mM) was added. Adding more D-glucose further decreased the CD signal, which then shifted into the negative region. This displacement method allows for adjusting the sensitivity across a broad dynamic range by controlling L-glucose concentration. This glucose sensing approach was tested in more complex media, specifically in 1×PBS buffer, which has high salt concentrations (NaCl: 137 mM, KCl: 2.7 mM, Na2HPO4: 10 mM, NaH2PO4: 1.8 mM). To prevent (Figure 51) aggregation of BPAT2+•2Cl–, first prepared was a mixture of L- glucose (50 mM) and BPAT2+•2Cl–(20 μM) in water, then lyophilized and redissolved in 1×PBS buffer. CD spectra were recorded following the addition of D-glucose. A continuous decrease in the induced CD signal at 260 nm was observed as the D-glucose concentration gradually increased from 0 to 17 mM (Figure 11c). This finding indicates the efficacy of BPAT2+•2Cl–in glucose sensing within physiologically relevant concentrations in the competitive environment of PBS buffer. General Method All commercially available solvents and chemicals were purchased from Sigma- Aldrich and Fisher Scientific and used without further purification unless otherwise stated. Water was deionized and micro-filtered through a Milli-Q water filtration system. Reactions were monitored by analytical thin-layer chromatography (TLC) on silica gel 60-F254 plates, visualized by an ultraviolet (254 nm) lamp. Nuclear magnetic resonance (NMR) spectra were recorded on the Varian Unity Inova 600 MHz spectrometer or Varian Unity Inova 400 MHz system. Variable temperature NMR experiment was conducted on Bruker Avance III 600 MHz system. The chemical shift was presented in ppm and referenced by residual non- deuterated solvent peaks (CDCl3: δ = 7.26 ppm, D2O: δ = 4.79 ppm, DMSO-d6: δ = 2.50 ppm). The1H DOSY NMR spectra were acquired using a convection-compensated gradient stimulated echo pulse sequence (DgsteSL_cc). Spectral processing was executed with Agilent VrnmJ 4.2 software, and subsequent extraction of diffusion coefficients was carried out using the Mono-exponential Fit feature in MestReNova 14.2. The experimental setup included a fixed delay of 50 ms. Gradient strength calculations adhered to the formula: ^!^!^!(∆ − ^ / 3), where γ denotes the gyromagnetic ratio, g the native gradient strength, δ the gradient duration, Attorney Docket No.11001-205WO1 and Δ the echo delay. High-resolution mass spectrometry (HRMS) was obtained on Agilent LC-MS QTOF 6540 using an ESI source or Waters Synapt G2 mass spectrometer using an ESI source. Matrix-assisted laser desorption / ionization- time of flight (MALDI-TOF) mass spectrometry was performed by Bruker UltrafleXtreme spectrometer using trans-2-[3-(4-tert- Butylphenyl)-2-methyl-2-propenylidene]malononitrile as a matrix substance. Circular dichroism spectra were recorded on the JASCO J-1500 Circular Dichroism Spectrophotometer. UV-Vis absorption spectra were collected by Thermo Scientific Evolution 201 UV / Vis Spectrometer. Flash Column chromatography was performed using a Biotage Selekt system with silica gel (SilicaFlash P60 from SILICYCLE) as the stationary phase. Isothermal titration was performed on the MicroCal iTC200 system, and samples were all filtered through a 0.45 µm PTFE filter before use. ITC Data were analyzed on MicroCal iTC200 analysis software. Detailed experimental procedures are provided below in the appropriate sections of this supporting information. Synthesis and Compounds Characterization Tetralactam macrocycle 3: A solution of pyridine-3,5-dicarbonyl dichloride1 (2.8 g, 13.7 mmol, 1.2 equiv.) in anhydrous CH2Cl2 (50 mL) was added dropwise over 6 h by a mechanical syringe pump into a stirred solution containing anthracene methylenediamine 2 (2.7g, 11.4 mmol, 1 equiv.) and Et3N (9.6 mL, 69 mmol, 6 equiv.) in anhydrous CH2Cl2 (700 mL). The reaction solution was stirred at room temperature for 20 h. When the reaction was complete, Et3N (15 mL) was added to the reaction solution, and the reaction mixture was filtered and rinsed with 40% MeOH / CH2Cl2. The filtrate was collected, and the solvent was removed by vacuum to get a light yellow solid. The residue was washed with water (150 mL), and then acetone (150 mL) to get the product tetralactam macrocycle 3 as a light yellow solid (534 mg, yield 13%). Rf = 0.4 (CH2Cl2: MeOH = 95: 5).1H NMR (400 MHz, CDCl3) δ 9.82 (s, 4H), 8.98 (s, 2H), 8.03 (d, J = 7.8 Hz, 8H), 7.89 , 5.59 (d, J = 4.5 Hz, 8H).13C NMR (101 MHz, CDCl3) δ 163.2, 162.8, 162.3, 161.9, 161.8, 145.6, 141.1, 133.1, 130.3, 127.5, 127.1, 123.8, 118.7, 115.9, 113.1, 110.2. The tetralactam macrocycle 3 exhibits poor solubility in CDCl3. To obtain high- resolution1H NMR and13C NMR spectra, a trace amount of TFA was introduced into the CDCl3 solution, thereby enhancing its solubility. HRMS(ESI) m / z: [M+H+]+Calcd for [C46H35N6O4]+735.2714; found:735.2696. BPAT2+•2Cl–: A solution of the tetralactam macrocycle 3 (200 mg, 0.272 mmol, 1 equiv.) and iodomethane (1.2 mL, 16.32 mmol, 60 equiv.) in DMF (3 mL) was stirred at 90 Attorney Docket No.11001-205WO1 ˚C for 40 h. After cooling to room temperature, the solvent was removed by vacuum to generate a yellow solid as pure BPAT2+•2I–.1H NMR (400 MHz, DMSO-d6) δ 9.58 (s, 4H), 9.35 (d, J = 5.4 Hz, 4H), 8.54 (s, 2H), 8.40 – 8.24 (m, 8H), 7.57 – 7.43 (m, 8H), 5.49 (d, J = 5.1 Hz, 8H), 4.55 (s, 6H). The solid was redissolved in hot DMSO (80 mL). A solution (20 mL) of KPF6 (5 g, 27.16 mmol, 100 equiv.) in DMSO was added to the previous solution followed by the addition of water (300 mL). The resulting precipitate was centrifuged, dried, and redissolved in MeCN (300 mL). A solution (100 mL) of tetrabutylammonium chloride (22 g, 82 mmol, 600 equiv.) in MeCN was added to form a precipitate, which was further washed with MeCN (200 mL) to get product BPAT2+•2Cl–as light- yellow solid (138 mg, yield 61%).1H NMR (600 MHz, D2O) δ 8.84 (d, J = 1.6 Hz, 4H), 8.37 (s, 2H), 8.29 – 8.13 (m, 8H), 7.59 (dd, J = 7.3, 2.9 Hz, 4H), 7.34 (d, J = 7.4 Hz, 4H), 5.80 (d, J = 15.1 Hz, 4H), 5.39 (d, J = 14.9 Hz, 4H), 3.01 (s, 6H).1H NMR (400 MHz, DMSO-d6) δ 9.59 (s, 4H), 9.49 (s, 4H), 8.70 (s, 2H), 8.33 (dd, J = 7.0, 3.4 Hz, 8H), 7.58 – 7.44 (m, 8H), 5.48 (d, J = 5.2 Hz, 8H), 4.54 (s, 6H).13C NMR (101 MHz, DMSO-d6) δ 161.4, 147.7, 139.9, 132.5, 129.9, 129.8, 126.0, 125.1, 48.6, 36.1. HRMS(ESI) m / z: [M–Cl–]+Calcd for [C48H40ClN6O4]+799.2800; found 799.2774. Imine macrocycle 5: Pyridine-3,5-dicarbaldehyde 4 (100 mg, 0.74 mmol, 1 equiv.) and anthracene methylenediamine 2 (175 mg, 0.74 mmol, 1 equiv.) were added to isopropanol (6 mL). The reaction mixture was stirred at 100°C overnight. The reaction was cooled to room temperature, and the solvent was removed under vacuum. The residue was washed with MeOH (10 mL x 2) to get the imine macrocycle 5 as a yellow solid (217 mg, yield 88%).1H NMR (400 MHz, CDCl3) δ 9.20 (s, 3H), 8.09 (d, J = 7.2 Hz, 8H), 7.78 (s, 3H), 7.42 (d, J = 9.7 Hz, 8H), 5.88 (s, 9H). MALDI-TOF m / z: [M+Na+]+Calcd for [C46H34N6Na]+693.3; found:693.7. Tetralactam macrocycle 3: A mixture of imine macrocycle 5 (200 mg, 0.298 mmol, 1 equiv.), NaClO2 (647 mg, 7.16 mmol, 24 equiv.), NH4Cl (128 mg, 2.38 mmol, 8 equiv.) and α-pinene (1.9 mL, 11.9 mmol, 40 equiv.) in anhydrous THF (5 mL) was stirred at 90 ˚C for 48 h. The solvent was then removed by vacuum. The residue was washed with water (12 mL x 3), acetone (10 mL x 3) and small amount of DMF (2 mL) to get the tetralactam macrocycle 3 as a yellow solid (130 mg, yield 59%). Binding Analysis Using1H NMR Titration and 2D NMR Spectroscopy. 1H NMR titrations in D2O were conducted at 298 K on a Varian Unity Inova 400 MHz system equipped with a cryoprobe. All samples were equilibrated for 24 h before use. Attorney Docket No.11001-205WO1 Aliquots from a stock solution containing the corresponding carbohydrate were added sequentially to an NMR tube containing the solution of BPAT2+•2Cl–(600 µL). The concentration of BPAT2+•2Cl–was calibrated using imidazole as an external standard through the comparison of their relative integrations. The1H NMR spectrum was acquired after each addition. The1H NMR titration spectra were analyzed by MestReNova software. The NMR titration isotherms were fitted to a 1:1 host-guest binding model using Thordarson’s equations at http: / / app.supramolecular.org / bindfit / . The data were then plotted using OriginLab software. The binding constants Ka were presented with standard deviations from the fitting outcomes. Isothermal Titration Calorimetry Isothermal titration was performed on the MicroCal ITC200 system at 23 °C. The experiments were conducted a titration cell with a working volume of 200 µL. The capacity of the injection syringe is 40 µL. The stirring speed was set at 750 rpm. Host and guest solutions were prepared in Milli- Q water. A stock solution of BPAT2+•2Cl–was prepared in Milli-Q water and filtrated. The concentration of BPAT2+•2Cl–was calibrated using a UV- Vis absorption spectrometry. All samples were equilibrated for 24 h before use. The host solution BPAT2+•2Cl–was placed in the titration cell, and the guests were loaded into the titration syringe. In each case, 20-25 injections were performed. The heat of dilution was measured by titrating the guest into a blank solution. The heat of dilution was subtracted before analyzing with MicroCal iTC200 software using a 1:1 host-guest binding model and plotted by Origin Lab software.X-Ray Single Crystallography Data and Analysis X-ray data and analysis for BPAT2+•2Cl–(CCDC: 2322712) X-ray diffraction data were measured on Bruker D8 Venture PHOTON II CMOS diffractometer equipped with a Cu Kα INCOATEC ImuS micro-focus source (λ = 1.54178 Å). Indexing was performed using APEX4 (Difference Vectors method). Data integration and reduction were performed using SaintPlus. Absorption correction was performed by the multi-scan method implemented in SADABS. The space group was determined using XPREP implemented in APEX3. The structure was solved using SHELXT and refined using SHELXL-2019 / 1 (full- matrix least-squares on F2) through the OLEX2 interface program. The ellipsoid plot was made with Platon. Crystals did not diffract past ~1.3 Å resolution and the resulting structure is of lower quality. Heavily disordered atoms were tentatively assigned as Cl- and acetone. Global RIGU and SIMU restraints were used, and restraints were used for Attorney Docket No.11001-205WO1 disordered atoms. The contribution of heavily disordered solvent content in structural voids was modeled by a solvent mask implemented in Olex2. Table 1. Crystal data and structure refinement for B49. Identification code B49 Empirical formula C54H52Cl2N6O6 X-ray data and analysis for BPAT2+●2Cl- complex (CCDC: 2322713) X-ray diffraction data were measured on Bruker D8 Venture PHOTON II CMOS diffractometer equipped with a Cu Kα INCOATEC ImuS micro-focus source (λ = 1.54178 Å). Indexing was performed using APEX4 (Difference Vectors method). Data integration and reduction were performed using SaintPlus. Absorption correction was performed by the multi-scan method implemented in SADABS. The space group was determined using XPREP implemented in APEX3. The structure was solved using SHELXT6and refined using SHELXL-2019 / 1 (full- matrix least-squares on F2) through the OLEX2 interface program. The ellipsoid plot was made with Platon. Due to the disorder of H2O / Cl-, the assignment of Cl63 and Cl64 to electron density was tentative. Some of the disordered atoms were refined as O (tentatively H2O). Table 2. Crystal data and structure refinement for D116. Identification code D116 Attorney Docket No.11001-205WO1 Formula weight 1119.59 Temperature / K 100.00 Computational Analysis Structural Optimization and Binding Energy Analysis The xyz coordinates for the calculations were extracted from the X-ray single crystal data. All optimizations and single-point calculations were performed with density functional theory (DFT) in the Orca program (version 5.0.3) using the Becke ‘88 exchange and Lee- Yang-Parr correlation (BLYP) functional, the Ahlrich’s double zeta Def2-SVP basis sets with geometrical counterpoise (gCP) scheme, and Grimme’s third-generation dispersion correction with Beck Johnson damping (D3BJ). In order to speed up the DFT optimizations, the Coulomb integral and numerical chain-of-sphere integration for the HF exchanges (RIJCOSX) method was applied with the Def2 / J auxiliary basis (AuxJ). All optimizations were performed in a water continuum with the Conductor-like Polarizable Continuum Model (CPCM) in Orca. Attorney Docket No.11001-205WO1 Electrostatic Potential Map: Single point energy calculations of BPAT2+and BPAT2+•2Cl–were performed at BLYP-SVP level. The resulting wavefunction files were used as input for the calculation of electron density and total electrostatic potential using Multiwfn 3.6 program based on computerized optimized code. The results were visualized using Chimera software. Visualization of Noncovalent Interactions Independent Gradient Model (IGM) analysis is an approach to identify and visualize intermolecular interactions. Strong polar attractions and weak van der Waals contacts are visualized as an iso-surface with blue and green colors, respectively. X-ray single crystal structures were used as input files. The binding surface was calculated by Multiwfn 3.6 program through function 20 (visual study of weak interaction) and visualized by Chimera software. Volume Calculation The volume of BPAT2+was calculated using MoloVol software. X-ray single crystal structure was used as input. Two spherical probes (small probe radius: 1.2 Å, large probe radius: 3 Å) were used to define cavities with a grid resolution of 0.2 Å and an optimization depth of 4. Molecular Dynamic Simulation Molecular dynamics simulations were performed using the Gromacs 2023.2 package. These simulations utilized the general AMBER force field (GAFF) for BPAT2+•2Cl–, a molecule not previously characterized in terms of force constants. As a result, the positions of the BPAT2+•2Cl–atoms were confined during the simulations. The amber99sb force field was employed for water molecules, along with the Tip4pEW explicit water model. For the BPAT2+•2Cl–, atomic charges were fitted to the Restrained Electrostatic Potential (RESP) using the Multiwfn program. This fitting was based on single point calculations derived from crystal structure geometries. These calculations were performed using the ORCA 5.0.3 package at the BLYP / SVP level of theory. The topology file of BPAT2+•2Cl–were prepared using the Sobtop 1.0 program. The simulations were conducted in an NPT ensemble, maintaining a constant temperature of 300 K. The simulation was performed within a 4.0 nm edge-length cubic box, designed to accommodate both the BPAT2+•2Cl–and the water molecules. The simulations spanned 10 nanoseconds with a time step of 1 femtosecond, following the energy minimization and equilibration of the systems. Attorney Docket No.11001-205WO1 Conformer search Conformer search was performed using Conformer-Rotamer Ensemble Sampling Tool (CREST) program. X-ray single crystal structures or DFT-optimized structures were used as input for the sampling. Constrains files were first created for anthracene panels and the rest of the resides in the input files was allowed for free movement during the sampling process. The MD / MTD time step was set as 1 fs, a GBSA implicit solvation for water was used, and the sampling was performed at the SQM level of GFN2- xTB. Conclusion In conclusion, the study introduces a synthetic lectin capable of capturing glucose in water with a remarkable binding affinity of 3001 M–1through an induced-fit binding process. This achievement underscores the effective combination of hydrogen bonding, hydrophobic effects, and electrostatic interactions in binding hydrophilic substrates in aqueous environments. The findings also reveal that rigid molecular skeletons in hydrogen bonding receptors may not always establish optimal noncovalent interactions with substrates. Instead, integrating flexible hydrogen bonding elements within the binding pocket enhances substrate binding via the induced-fit mechanism. Additionally, an allosteric modulation mechanism in this receptor is discussed herein. Chloride binding at allosteric sites triggers receptor aggregation, which in turn rigidifies the binding pocket, impedes the induced-fit process, and consequently decreases affinity. This behavior mirrors the sophisticated adaptability found in biological receptors, marking a significant step in the development of advanced biomimetic receptors. These insights contribute to a deeper understanding of molecular recognition in complex biological systems. Furthermore, the synthetic lectin acts as a highly sensitive glucose sensor in various aqueous solutions, including water and PBS buffer, highlighting its potential for biomedical applications. These results not only demonstrate the feasibility of mimicking the sophisticated adaptability of bioreceptors in synthetic molecular receptors but also pave the way for the development of advanced biomimetic receptors. Example 2: Pyridinium-Based Tetralactam Macrocycle for Enhanced Sugar Recognition in Water Introduction The complex distribution of functional groups in carbohydrates, coupled with their strong solvation in water, makes them challenging targets for synthetic receptors. Despite extensive research into various molecular frameworks, most synthetic carbohydrate receptors have exhibited low affinities, and their interactions with sugars in aqueous environments Attorney Docket No.11001-205WO1 remain poorly understood. Presented herein is a pyridinium-based hydrogen-bonding receptor derived from a subtle structural modification of a well-known tetralactam macrocycle. This small structural change resulted in a dramatic enhancement of glucose binding affinity, increasing from 56 M⁻¹ to 3001 M⁻¹. Remarkably, the performance of the synthetic lectin surpasses that of the natural lectin, Concanavalin A, by over fivefold. X-ray crystallography of the macrocycle-glucose complex reveals a distinctive hydrogen bonding pattern, which allows for a larger surface overlap between the receptor and glucose, contributing to the enhanced affinity. Furthermore, this receptor possesses allosteric binding sites, which involve chloride binding and trigger receptor aggregation. This unique allosteric process reveals the critical role of structural flexibility in this hydrogen-bonding receptor for the effective recognition of sugars. Also demonstrated herein is the potential of this synthetic lectin as a highly sensitive glucose sensor in aqueous solutions. The design of synthetic receptors capable of recognizing hydrophilic substrates in water stands as a challenging topic in modern supramolecular chemistry. Water, as a good hydrogen bond donor and acceptor, competes heavily with the polar substrates and synthetic receptors, hindering the establishment of effective interactions. Additionally, the low solubility of most organic building blocks further complicates the development of water- soluble receptors. This issue is particularly pronounced in the design of synthetic receptors for carbohydrates. The structural complexity and hydrophilic nature of sugars make them tricky targets for both natural and synthetic receptors. Even lectins —proteins evolved specifically for carbohydrate recognition — often exhibit weak interaction with sugars, with binding affinities (Ka) typically below 103M–1. The development of synthetic lectins capable of efficiently binding sugars in water remains a critical yet unsolved problem. Addressing this challenge is crucial for advancing a wide range of biomedical applications, including diabetes management, the development of synthetic antibody for targeting cancer cells, anti-infective and anti-inflammatory therapies, as well as many diagnostics tools. A promising strategy has involved leveraging hydrogen bonding and hydrophobic interactions within an intricately designed temple-shaped molecular framework. For example, a tricyclic molecular cage was initially designed48for glucose binding with a binding affinity of 9.5 M–1in water, achieved by combining the hydrophobic surfaces of two parallel biphenyl panels with eight amide hydrogen bonding residues. Subsequent structural optimizations have involved using larger aromatic panels, such as anthracene and pyrene, and variations in the number and location of hydrogen bonding residues. While these modifications have led to improvements in selectivity and affinity, the synthesis of these receptors remains complex, Attorney Docket No.11001-205WO1 and their carbohydrate-binding affinities are generally weak. Moreover, the lack of single crystal structures of the synthetic carbohydrate receptors associated with sugars hinders the understanding of how synthetic receptors interact with carbohydrates in aqueous environments. To date, only one such structure has been reported, making it difficult to fully elucidate binding mechanisms and guide receptor design. Thus, there is a pressing need for general molecular design principles to develop synthetic lectins capable of more efficient carbohydrate recognition in water. In the quest to unravel the complexities of molecular recognition directed by hydrogen bonding in water, a dynamic approach to access a pyridinium-based tetralactam macrocycle with two parallel durene panels is introduced. This macrocycle can be easily synthesized through dynamic imine chemistry followed by a Pinnick oxidation reaction. Although the macrocycle exhibits a high affinity of 850 M–1for glucose in water, the origin of this high affinity and its binding pattern with glucose remained unclear. In the current research, a synthetic lectin that is structurally similar to an anthracene macrocycle reported by the Davis group is presented but shows significantly improved binding affinity from 56 M–1to 3000 M–1. The performance of the synthetic lectin surpasses the natural lectin Concanavalin A by more than five times. The X-ray single crystal structure of the macrocycle is obtained in complex with glucose. Compared to the Davis macrocycle, the structure reveals a distinct hydrogen bonding pattern that enables a larger overlapping surface area between the receptor and glucose, resulting in enhanced binding affinity. This significant improvement, driven by subtle structural variations, highlights the sensitivity of sugar binding to the microenvironment within the synthetic lectin’s binding pocket, offering valuable insights for the future design of more effective synthetic lectins. Furthermore, the receptor is equipped with two allosteric binding sites for chloride ions, which initiate receptor aggregation and further rigidification of the binding pocket. This allosteric effect provides critical insights into the role of structural flexibility in this hydrogen-bonding receptor for effective sugar recognition in water. Additionally, the potential of the synthetic lectin is demonstrated as a highly sensitive glucose sensor in aqueous solutions. This research not only sheds light on the mechanisms of hydrogen bonding in water but also advances the development of practical applications for synthetic lectins. Results and Discussion Structural design and synthesis Attorney Docket No.11001-205WO1 In the design, BPAT2+•2Cl–was introduced, inspired by the synthetic lectins developed by the groups of Davis, Roelens, and Francesconi (Fig. 71). This structure is characterized by two large anthracene walls, creating a hydrophobic cavity that provides a substantial contact surface with sugars. A noticeable structure characteristic of BPAT2+•2Cl–is its four convergent NH hydrogen bonds, which converge towards the binding pocket as a result of steric hindrance between protons c and d. These features coalesce to form an amphiphilic binding pocket, blending polar hydrogen-bonding elements within a nonpolar, nanoconfined space. Furthermore, the integration of two pyridinium bridges enhances the design in several ways: Firstly, the para C–H bonds, polarized by the pyridinium units, act as effective hydrogen bond donors, pointing convergently towards the binding pocket. Secondly, the receptor’s association with the hydrophilic counterion Cl–ensures good water solubility. Lastly, the methyl group and ortho protons on the pyridinium ring potentially serve as an allosteric binding site, offering a pathway to modulate the substrate binding. A precursor to the synthesis BPAT2+•2Cl–is the tetralactam macrocycle 3. This macrocycle can be obtained (Fig. 2) through a conventional approach under high dilution conditions, leading to a modest yield of 13%. While this method benefits from the low solubility of 3, facilitating purification by solvent washing, it suffers from low yield. Consequently, an alternative synthetic strategy was explored. A dynamic approach employing the condensation of anthracene methylene diamine 2 with a pyridine 3,5-bisaldehyde precursor 4 provides imine macrocycle 5 in an excellent 88% yield. This intermediate can be converted to the desired tetralactam 3 via a Pinnick oxidation with a satisfactory 59% yield. Subsequent alkylation of 3 with iodomethane, followed by ion exchange, furnishes the water- soluble BPAT2+•2Cl–in a good yield of 61%. X-ray single crystal structure of BPAT2+•2Cl–was obtained by slow evaporation of a solution of BPAT2+•2Cl–dissolved in a mixture of acetone and water over three weeks. In the solid state, BPAT2+•2Cl–adopts (Fig. 3A) a unique binding pocket formed by two parallel anthracene panels separated by a distance of 7.3 Å. Steric hindrance between the methylene protons and anthracene rings forces all four NH residues to converge toward the pocket. Using a two spherical probes method, the volume of the binding pocket was calculated (Fig.126) to be 138 ų, which is slightly larger than cucurbit[6]uril (119 ų) but smaller than cucurbit[7]uril (205 ų). To understand the interaction between BPAT2+•2Cl–and water, a 10 ns molecular dynamics simulation under NPT ensemble at 300 K was performed. The result (Fig. 3D) shows the hydrated macrocycle accommodating an average of 8.7 water molecules within its Attorney Docket No.11001-205WO1 binding pocket. The size-restricted binding pocket of BPAT2+•2Cl–compels some of these cavity water molecules to form [CH•••π] interactions with the anthracene panels instead of hydrogen bonding with other water molecules. Consequently, these cavity water molecules only form an average of 2.96 hydrogen bonds, significantly less than the 3.62 observed in bulk water. Upon release to the bulk, these poorly hydrogen-bonded cavity water molecules are expected to dissociate from [CH•••π] interactions and reform more hydrogen bonds with bulk water molecules, potentially providing a favorable change of enthalpy when guest molecules displace these cavity water molecules from the binding pocket. Aggregation of BPAT2+•2Cl–A property of BPAT2+•2Cl–that is not observed in previously reported Davis tetralactam macrocycles is its aggregation behavior in water. This characteristic is evidenced by the concentration-dependent behavior displayed (Fig. 5) in1H NMR spectra of BPAT2+•2Cl–. Below 25 µM, the macrocycle exists in its free state, characterized by a distinct set of peaks (red). As the concentration increases to 150 µM, new peaks (blue) gradually emerge in the upfield region, indicating the formation of aggregates. Above 150 µM, over 90% of the macrocycle adopts this aggregated form. The coexistence of both sets of peaks suggests a slow exchange between the free and aggregated states. To further probe this aggregation behavior, diffusion-ordered spectroscopy (DOSY) experiments were performed on three BPAT2+•2Cl–samples in D2O at varying concentrations (0.02, 0.2, and 0.8 mM). The lowest concentration (0.02 mM) displayed (Fig. 31A-31D) a diffusion coefficient of 2.31 × 106cm2 / s, corresponding to a hydrodynamic radius of 1.07 nm for a spherical hydrated BPAT2+•2Cl–cluster. Notably, at 0.2 mM, the diffusion coefficient dropped to 1.13 × 106cm2 / s, indicating a significantly larger hydrodynamic radius of 2.17 nm. The 0.8 mM sample revealed a slightly larger hydrodynamic radius of 2.27 nm compared to the 0.2 mM sample. The effect of concentration on the size of the aggregates was independently confirmed by atomic force microscopy (AFM) imaging. For the sample measured at a 0.02 mM concentration, particles with a molecular height of 0.7 to 1.1 nm were observed (Fig. 125), matching the size of the macrocycle. At a concentration of 0.2 mM, larger particles with an average diameter of 2.1 nm were observed. The aggregation behavior of BPAT2+•2Cl–is markedly dependent on temperature, as shown by variable temperature (VT)1H NMR spectra (Fig.78) of a 0.2 mM sample in D2O. At temperatures below 25˚C, a predominant aggregation of the sample was observed. From 35˚C to 55˚C, there is a gradual shift from the aggregated BPAT2+•2Cl–to its free form. Above Attorney Docket No.11001-205WO1 65˚C, the macrocycle fully dissociates, indicating a complete transition to the free state. Notably, the slow exchange between these two states on the1H NMR timescale allows for the convenient determination of equilibrium constants for the aggregation process across these temperatures by comparing (Fig. 78 and Table 1) their differences in integration numbers. The corresponding Van’t Hoff plot analysis revealed the aggregation of BPAT2+•2Cl–is an enthalpy-driven process with a large entropy penalty, suggesting the electrostatic interactions between chloride ions and the macrocycles are essential for this distinct aggregation mechanism. To validate the hypothesis that the chloride binding acts as the driving force governing the aggregation behavior, a chloride titration experiment was conducted using a 0.017 mM solution of BPAT2+•2Cl–in D2O. The gradual addition of Cl–ions promoted (Fig. 6) the formation of a second set of peaks, mirroring the aggregation patterns observed at higher BPAT2+•2Cl–concentrations. This aggregation at such a low macrocycle concentration suggests that electrostatic interactions between the positively charged BPAT2+and Cl–are the critical driving force to trigger the aggregation. The formation of ion pairs effectively neutralizes the charge of BPAT2+, leading to a decrease in its water solubility. This reduction in solubility, when combined with the large hydrophobic surface of the anthracene segments, induces aggregation. The Cl––triggered aggregation was independently verified by a UV-Vis titration experiment (Fig. 60A-60D), where adding NaCl to a BPAT2+•2Cl–solution (2 μM) resulted in decreased and red-shifted absorption peaks. Notably, the hydrophobic effect is another driving force for the aggregation. When over 10% v / v CD3CN was introduced to a D2O solution of BPAT2+•2Cl–(Fig.106), its1H NMR spectrum changed from the aggregated form to the free form, suggesting that the aggregation was disrupted by mitigating the hydrophobic effect. Evaluation of sugars binding in water The interaction between free BPAT2+•2Cl–and sugars in water was investigated using1H NMR titration. A solution of BPAT2+•2Cl–(17 μM) in D2O was titrated with aliquots of glucose, and1H NMR spectra were recorded after each addition. Notably, the stacked spectra in Fig.4A reveal that only proton b in BPAT2+•2Cl–exhibited a downfield shift upon glucose binding, suggesting its role in the binding process. Considering the inward orientation of proton b, this observation strongly suggests glucose binding within the binding pocket through [C–H•••O] hydrogen bonding with the macrocycle. Furthermore, the downfield shift implies a stronger [C–H•••O] interaction between the macrocycle and glucose compared to cavity water. A separation experiment was conducted by mixing BPAT2+⋅2Cl−(0.4 mM) and Attorney Docket No.11001-205WO1 glucose in 1:1 and 1:2 molar ratios. This experiment showed (Fig. 98) upfield shifts in the glucose protons, suggesting that glucose is encapsulated within the binding cavity of the macrocycle. Nonlinear fitting of the proton b’s chemical shift changes against the guest / host ratio (Fig. 4B and 4C) revealed a remarkable binding affinity of 3001±56 M–1. This result represents one of the highest reported affinities for synthetic lectins binding with sugars in water, a testament to the effectiveness of the BPAT2+•2Cl–design. BPAT2+•2Cl–exhibits a binding affinity for glucose 5.8 times greater than that of the frequently employed lectin, concanavalin A, which possesses a binding constant (Ka) of 520 M–1. Compared to the previous durene-based macrocycle, replacing the smaller durene panels with larger anthracene walls impressively enhanced the affinity by a factor of 3.6. This improvement highlights the contribution of the extended π-system to the binding interaction. Furthermore, the cationic pyridinium units contribute to the observed high affinity. A structurally similar anionic macrocycle with an isophthalamide unit (Fig.71) only registered an affinity of 56 M–1, demonstrating the importance of the polarized C–H bonds provided by the pyridinium groups in BPAT2+•2Cl–. These additional hydrogen bond donors significantly enhance the complex stability, contributing to the high binding affinity for glucose. The strong affinity between BPAT2+•2Cl–and glucose was further corroborated by isothermal titration calorimetry (ITC) experiments (Fig. 4D). The ITC data revealed strong exothermic peaks upon glucose binding, indicating favorable enthalpic interactions. Nonlinear fitting of the binding isotherm using a 1:1 binding model yielded a binding constant of (2400±119) M–1, consistent with the1H NMR titration results. Notably, the binding process was characterized by a strong binding enthalpy (∆H) of −11.8 kcal / mol, accompanied by a substantial entropy penalty (T∆S) of −7.2 kcal / mol. This enthalpy-driven binding suggests that the interaction is primarily governed by comprehensive hydrogen bonding between glucose and the macrocycle. The enthalpic contribution likely arises from two factors: stronger hydrogen bonds between glucose and the macrocycle compared to those involving cavity water and the release of cavity water molecules that can subsequently form additional hydrogen bonds with bulk water. These energetically favorable interactions outweigh the entropic cost associated with restricted conformational and translational freedom of the macrocycle and glucose within the complex. Table 3. A summary of association constants for 1:1 complexes of BPAT2+•2Cl–with sugars in D2O or H2O as determined by1H NMR titrations and ITC at 23 ˚C. carbohydrates Free state Ka ( M–1) Aggregated state Ka ( M–1) Attorney Docket No.11001-205WO1 NMR ITC NMR ITC glucose 3001 ± 56 2410 ± 119 90 ± 1 76 ± 1 gh1H NMR titration experiments. Notably, glucose exhibits the highest binding affinity. This pronounced preference underscores the vital role played by the unique arrangement of hydroxyl groups on the glucose ring, which aligns well with the binding pocket of BPAT2+•2Cl–. Methyl-β- glucoside, structurally analogous to glucose but differentiated by a methyl group at the C1 position, shows a diminished affinity of (1189±16) M–1. This variation implies that even subtle alterations in the sugar structure can profoundly influence binding affinity. A more striking example is methyl-α-glucoside, where the orientation of the C1 hydroxyl group is altered to an axial position, resulting in a binding affinity that drops by more than 12-fold. This observation emphasizes the criticality of the equatorial positioning of hydroxyl groups for optimal interaction with the macrocycle. Exploring sugars beyond glucose, including mannose, galactose, and psicose, which do not possess an all-equatorial hydroxyl group arrangement, revealed significantly weaker binding affinities. This pattern agrees with the observation that the binding pocket of BPAT2+•2Cl–is intricately tailored to accommodate the equatorial hydroxyl configuration specific to glucose. Even cellobiose, a disaccharide comprised of two β-glucose units, only demonstrates a moderate affinity of (592±16) M–1, suggesting that the binding pocket of BPAT2+•2Cl–is too small to accommodate larger sugar molecules. Similarly, maltose mirrors that of cellobiose, attributable to its glucose unit. Complementary insights were gained from ITC experiments, which revealed a similar trend in binding affinities and selectivity to those observed in the1H NMR titration. Notably, the binding of glucose exhibited a significantly higher enthalpy compared to methyl-β- glucoside. This substantial difference in binding enthalpy suggests that the macrocycle’s selectivity for glucose over methyl-β-glucoside is due to the formation of a more extensive hydrogen bonding network. This aspect will be further discussed in the crystal structure Attorney Docket No.11001-205WO1 analysis section. Collectively, these findings delineate the extraordinary selectivity of BPAT2+•2Cl–for glucose. The precise complementarity between the hydroxyl groups of the sugar and the macrocycle’s binding pocket, coupled with the pronounced sensitivity to structural variations, highlights the sophisticated nature of this molecular recognition mechanism. The glucose binding properties of BPAT2+•2Cl–was further investigated in its aggregated state. These examples were conducted at a high concentration of BPAT2+•2Cl–(0.5 mM), supplemented with 20 mM NaCl to enhance the stability of the aggregate. A separate titration of BPAT2+•2Cl−at 0.2 mM using glucose without NaCl revealed (Fig.95) that part of the aggregated BPAT2+•2Cl−dissociated into its free state upon glucose binding. The apparent binding affinity under this condition was determined to be 783±62 M−1using ITC (Fig. 112). Over the course of 24 hours, glucose binding gradually disrupted the aggregation of BPAT2+•2Cl−(Fig. 99), leading to the formation of individual glucose⊂ BPAT2+complexes. The1H NMR spectrum of these complexes matches the spectrum measured at a low concentration (0.017 mM) of BPAT2+•2Cl−, where it exists in its free state. In contrast, no dissociation of the aggregation was observed (Fig.100 and 101) over 25 days in the presence of NaCl, suggesting NaCl can significantly stabilize the aggregate. The glucose binding behavior in the aggregated state of BPAT2+•2Cl–is notably different from its behavior in the free state (Fig.7A). Specifically, it’s noted that the inward- facing protons b’ exhibited an upfield shift upon adding glucose. This shift suggests a decrease in hydrogen bonding strength with glucose compared to their interaction with cavity water. Concurrently, one set of anthracene protons (e’) exhibited a downfield shift, while one set of methylene signals from proton c’ split into two distinct sets of peaks. The remaining peaks from protons e’ and c’ remained almost unchanged during the entire titration process. These observations suggest that, under the conditions of the titration experiment, BPAT2+•2Cl–maintains its aggregated form while engaging in glucose binding without compromising its structural integrity. In further analysis, change in chemical shift was fitted the for proton b’ against the guest / host ratio using a 1:1 binding model, as illustrated in Fig. 66f and 66g. This analysis yielded an affinity of (90±1) M–1. This finding was corroborated by ITC experiments, which indicated (Fig. 66h) a binding affinity of (76±1) M–1. The binding isotherm from ITC also revealed a binding enthalpy of –5.2 kcal / mol, which is 6.6 kcal / mol weaker than the glucose binding observed in the free state of BPAT2+•2Cl–. The glucose binding of BPAT2+•2Cl–in its aggregated state still suffers from an entropy penalty (T∆S) of –2.6 kcal / mol. This penalty Attorney Docket No.11001-205WO1 is much lower than that observed during glucose binding in the free state of BPAT2+•2Cl–. The general trend of sugar binding by BPAT2+•2Cl–in its aggregated state mirrors its free state, albeit binding affinities reduced by factors ranging from 4–30. This result indicates that the aggregation of BPAT2+•2Cl–does not alter its glucose selectivity compared to other sugars. Computational analysis, including DFT calculations and conformational sampling, indicates (Figs. 9A-9F, 127A-127B) that in its aggregated state, BPAT²⁺•2Cl⁻ becomes rigidified due to aromatic stacking between the pyridinium units and anthracene panels. This structural rigidity compromises the macrocycle’s ability to adapt its conformation to match the complex functional group distributions of sugars, lowering its binding affinity for sugars. These findings suggest that when designing hydrogen-bonding receptors for substrates with multiple binding sites, incorporating a certain level of structural flexibility is crucial, even while aiming for a preorganized binding pocket. The formation of a complex between glucose and BPAT2+•2Cl–was further solidified by two additional experiments. Nuclear Overhauser effect spectroscopy (NOESY) provided crucial spatial information, revealing several through-space correlation peaks between protons b, d, and e on the macrocycle and C–H protons on glucose (Fig.76). This observation directly confirms the proximity between the two molecules in D2O. High-resolution mass spectrometry (HRMS) provided further validation, with a peak at m / z 979.3444 matching the theoretical m / z of 979.3433 for the [BPAT2+•glucose•Cl–]+adduct (Fig. 17 and 18) with a molecular formula of [C54H52ClN6O10]+. These findings conclusively demonstrate the stoichiometry and formation of the complex. Structure elucidation by X-ray crystallography Single crystals of glucose⊂ BPAT2+•2Cl–were successfully grown by slowly evaporating an aqueous solution containing glucose (50 mM), BPAT2+•2Cl–(0.5 mM), and NaCl (20 mM) over three months. In this structure (Fig. 66a), each glucose molecule forms eight hydrogen bonds with the inward-facing CH and NH hydrogen bond donors of the macrocycle. Additionally, the glucose’s axial C–H bonds are sandwiched between two parallel anthracene panels spaced 7.9 Å apart, an optimal distance for establishing multiple [C–H•••π] interactions. This spacing, which extended from 7.3 Å to 7.9 Å, highlights the binding pocket’s flexibility in BPAT2+•2Cl–. By comparing this crystal structure with the one reported by Davis, the receptor exhibits an entirely different binding pattern with glucose (Fig. 66d-66i), despite the structural similarity between the two macrocycles. First, it was observed that one side of the macrocycle forms hydrogen bonds with the C3 and C4 hydroxyl Attorney Docket No.11001-205WO1 groups on glucose, while the other side forms hydrogen bonds with the C6 hydroxyl group and the pyranose oxygen. In contrast, Davis’s macrocycle only forms hydrogen bonds with the hydroxyl groups on the C1, C2, C3, and C4 carbons. Second, the macrocycle covers 91% of the van der Waals surface of the glucose, whereas Davis’s macrocycle covers only 76% of the glucose surface area. This difference in the hydrogen bonding pattern allows the macrocycle to create a larger contact surface, which is believed to be the primary reason for the higher affinities observed in the system. This result also suggests that the binding of carbohydrates is highly sensitive to slight modifications in the receptor’s structure, which is an important consideration when designing new receptors for sugars. Notably, the glucose remains hydrated within the hydrophobic binding pocket of the macrocycle, engaging in hydrogen bonding with four external water molecules. The 2 and 3- hydroxyl groups of the glucose also interact with a chloride anion via hydrogen bonding. In total, each glucose substrate is involved in 14 hydrogen bonds, encompassing interactions with the macrocycle, chloride ions, and water molecules. A particularly intriguing finding (Fig.66c) is an indirect interaction of the 1-hydroxyl group of glucose with a carbonyl group from the macrocycle, mediated by two water bridges. This observation suggests a novel role for solvent water in receptor-substrate binding, facilitating indirect hydrogen bonding. This additional hydrogen bonding could be responsible for the higher glucose selectivity over the methyl-β-glucoside. Each macrocycle engages (Fig. 66A) in ion pairing with two Cl−anions. These ion pairs are sustained by [C–H•••Cl−] hydrogen bonds formed between the chloride anion and the protons of both the methyl group and the ortho protons on the pyridinium units, further stabilized by electrostatic interactions. These chloride binding sites, situated externally to the main binding pocket, act as allosteric regulators, influencing the macrocycle’s affinity for glucose. Glucose sensing To explore the potential of BPAT2+•2Cl−as a glucose-responsive material, its sensitivity to variations in glucose concentrations in both free and aggregated states was assessed. In its free state, BPAT2+•2Cl−reaches saturation at a 2 mM concentration due to its high affinity for glucose, as shown in Fig. 12. As a result, within the physiological glucose concentration range of 4 to 15 mM, further increases in glucose levels cause negligible changes in the circular dichroism (CD) signal. Conversely, in its aggregated state, BPAT2+•2Cl−exhibits lower affinity, leading (Figs. 15-17) to a noticeable variation in the induced CD signals within the physiological range of 5–10 mM glucose concentrations. This Attorney Docket No.11001-205WO1 characteristic of showing a continuous response to glucose concentration fluctuations within the physiological range underscores its value in the development of glucose-responsive materials based on synthetic receptors. Thus, despite its lower affinity, aggregated BPAT2+•2Cl−offers distinct advantages in responding to changes in physiological glucose levels compared to the free BPAT2+•2Cl−, which shows stronger binding for glucose. To further demonstrate the potential of BPAT2+•2Cl–as a glucose sensor, L-glucose was introduced as both an indicator and competitor. Notably, L-glucose induced (Fig. 61A- 61D) a reverse cotton effect in the CD spectrum of the complex. This approach effectively addresses the saturation issue of free BPAT2+at physiological glucose concentrations. In an experiment, a mixture of BPAT2+•2Cl–(10 µM) and L-glucose (15 mM) in water produced a positive induced CD signal at 260 nm. The subsequent addition of D-glucose gradually displaced (Fig. 16) the L-glucose, reducing the CD signal to zero when an equal amount of D-glucose (15 mM) was added. Adding more D-glucose further decreased the CD signal, which then shifted into the negative region. This displacement method allows for adjusting the sensitivity across a broad dynamic range by controlling L-glucose concentration. The glucose sensing approach was also tested in more complex media, specifically in 1×PBS buffer with high salt concentrations (NaCl: 137 mM, KCl: 2.7 mM, Na2HPO4: 10 mM, NaH2PO4: 1.8 mM). To prevent (Fig. 96) aggregation of BPAT2+•2Cl–,a mixture of L- glucose (50 mM) and BPAT2+•2Cl–(10 μM) was first prepared in water, then lyophilized it and redissolved it in 1×PBS buffer. CD spectra were recorded following the addition of D- glucose. A continuous decrease in the induced CD signal at 260 nm was observed as the D- glucose concentration gradually increased from 0 to 17 mM (FIG.16). This finding indicates the efficacy of BPAT2+•2Cl–in glucose sensing within physiologically relevant concentrations in the competitive environment of PBS buffer. General Method All commercially available solvents and chemicals were purchased from Sigma- Aldrich and Fisher Scientific and used without further purification unless otherwise stated. Water was deionized and micro-filtered through a Milli-Q water filtration system. Reactions were monitored by analytical thin-layer chromatography (TLC) on silica gel 60-F254 plates, visualized by an ultraviolet (254 nm) lamp. Nuclear magnetic resonance (NMR) spectra were recorded on the Varian Unity Inova 600 MHz spectrometer or Varian Unity Inova 400 MHz system. Variable temperature NMR experiment was conducted on Bruker Avance III 600 MHz system. The chemical shift was presented in ppm and referenced by residual non- Attorney Docket No.11001-205WO1 deuterated solvent peaks (CDCl3: δ = 7.26 ppm, D2O: δ = 4.79 ppm, DMSO-d6: δ = 2.50 ppm). The1H DOSY NMR spectra were acquired using a convection-compensated gradient- stimulated echo pulse sequence (DgsteSL_cc). Spectral processing was executed with Agilent VrnmJ 4.2 software, and diffusion coefficient extraction was performed using the Mono- exponential Fit feature in MestReNova 14.2. The experimental setup included a fixed delayof 50 ms. Gradient strength calculations adhered to the formula: ^^^^^^^∆ − ^ / 3^, where γdenotes the gyromagnetic ratio, g the native gradient strength, δ the gradient duration, and Δ the echo delay. High-resolution mass spectrometry (HRMS) was obtained on Agilent LC-MS QTOF 6540 using an ESI source or Waters Synapt G2 mass spectrometer using an ESI source. Matrix-assisted laser desorption / ionization-time of flight (MALDI-TOF) mass spectrometry was performed by Bruker UltrafleXtreme spectrometer using trans-2-[3-(4-tert-Butylphenyl)- 2-methyl-2-propenylidene]malononitrile as a matrix substance. Circular dichroism spectra were recorded on the JASCO J-1500 Circular Dichroism Spectrophotometer. UV-Vis absorption spectra were collected by Thermo Scientific Evolution 201 UV / Vis Spectrometer. Flash Column chromatography was performed using a Biotage Selekt system with silica gel (SilicaFlash P60 from SILICYCLE) as the stationary phase. Isothermal titration was performed on the MicroCal iTC200 system, and samples were all filtered through a 0.45 µm PTFE filter before use. ITC Data were analyzed using MicroCal iTC200 analysis software. Detailed experimental procedures are provided below in the appropriate sections of this supporting information. Synthesis and Compounds Characterization Tetralactam macrocycle 3: A solution of pyridine-3,5-dicarbonyl dichloride1 (2.8 g, 13.7 mmol, 1.2 equiv.) in anhydrous CH2Cl2(50 mL) was added dropwise over 6 h by a mechanical syringe pump into a stirred solution containing anthracene methylenediamine 2 (2.7g, 11.4 mmol, 1 equiv.) and Et3N (9.6 mL, 69 mmol, 6 equiv.) in anhydrous CH2Cl2(700 mL). The reaction solution was stirred at room temperature for 20 h. When the reaction was complete, Et3N (15 mL) was added to the reaction solution, and the reaction mixture was filtered and rinsed with 40% MeOH / CH2Cl2. The filtrate was collected, and the solvent was removed by vacuum to get a light yellow solid. The residue was washed with water (150 mL) and then acetone (150 mL) to get the product tetralactam macrocycle 3 as a light yellow solid (534 mg, yield 13%). Rf = 0.4 (CH2Cl2: MeOH = 95: 5).1H NMR (400 MHz, CDCl3) δ 9.82 (s, 4H), 8.98 (s, 2H), 8.03 (d, J = 7.8 Hz, 8H), 7.89 , 5.59 (d, Attorney Docket No.11001-205WO1 J = 4.5 Hz, 8H).13C NMR (101 MHz, CDCl3) δ 163.2, 162.8, 162.3, 161.9, 161.8, 145.6, 141.1, 133.1, 130.3, 127.5, 127.1, 123.8, 118.7, 115.9, 113.1, 110.2. The tetralactam macrocycle 3 exhibits poor solubility in CDCl3. To obtain high- resolution1H NMR and13C NMR spectra, a trace amount of TFA as an additive was introduced into the CDCl3 solution, enhancing its solubility. HRMS(ESI) m / z: [M+H+]+Calcd for [C46H35N6O4]+735.2714; found:735.2696. BPAT2+•2Cl–: A solution of the tetralactam macrocycle 3 (200 mg, 0.272 mmol, 1 equiv.) and iodomethane (1.2 mL, 16.32 mmol, 60 equiv.) in DMF (3 mL) was stirred at 90 ˚C for 40 h. After cooling to room temperature, the solvent was removed by vacuum to generate a yellow solid as pure BPAT2+•2I–.1H NMR (400 MHz, DMSO-d6) δ 9.58 (s, 4H), 9.35 (d, J = 5.4 Hz, 4H), 8.54 (s, 2H), 8.40 – 8.24 (m, 8H), 7.57 – 7.43 (m, 8H), 5.49 (d, J = 5.1 Hz, 8H), 4.55 (s, 6H). The solid was redissolved in hot DMSO (80 mL). A solution (20 mL) of KPF6 (5 g, 27.16 mmol, 100 equiv.) in DMSO was added to the previous solution, followed by the addition of water (300 mL). The resulting precipitate was centrifuged, dried, and redissolved in MeCN (300 mL). A solution (100 mL) of tetrabutylammonium chloride (22 g, 82 mmol, 600 equiv.) in MeCN was added to form a precipitate, which was further washed with MeCN (200 mL) to get product BPAT2+•2Cl–as light-yellow solid (138 mg, yield 61%).1H NMR (600 MHz, D2O) δ 8.84 (d, J = 1.6 Hz, 4H), 8.37 (s, 2H), 8.29 – 8.13 (m, 8H), 7.59 (dd, J = 7.3, 2.9 Hz, 4H), 7.34 (d, J = 7.4 Hz, 4H), 5.80 (d, J = 15.1 Hz, 4H), 5.39 (d, J = 14.9 Hz, 4H), 3.01 (s, 6H).1H NMR (400 MHz, DMSO-d6) δ 9.59 (s, 4H), 9.49 (s, 4H), 8.70 (s, 2H), 8.33 (dd, J = 7.0, 3.4 Hz, 8H), 7.58 – 7.44 (m, 8H), 5.48 (d, J = 5.2 Hz, 8H), 4.54 (s, 6H).1H NMR (400 MHz, D2O, 0.8 mM) δ 8.90 (s, 4H), 8.49 (s, 2H), 8.38 – 8.21 (m, 8H), 7.66 (dd, J = 7.0, 3.1 Hz, 4H), 7.40 (d, J = 7.8 Hz, 4H), 5.84 (d, J = 15.0 Hz, 4H), 5.46 (d, J = 15.1 Hz, 4H), 3.08 (s, 6H).1H NMR (400 MHz, D2O, 0.017 mM) δ 9.57 (s, 4H), 8.96 (s, 2H), 8.27 (s, 8H), 7.57 (d, J = 7.9 Hz, 8H), 5.52 (s, 8H), 4.64 (s, 6H).13C NMR (101 MHz, DMSO-d6) δ 161.4, 147.7, 139.9, 132.5, 129.9, 129.8, 126.0, 125.1, 48.6, 36.1. HRMS(ESI) m / z: [M–Cl–]+Calcd for [C48H40ClN6O4]+799.2800; found 799.2774. Imine macrocycle 5: Pyridine-3,5-dicarbaldehyde 4 (100 mg, 0.74 mmol, 1 equiv.) and anthracene methylenediamine 2 (175 mg, 0.74 mmol, 1 equiv.) were added to isopropanol (6 mL). The reaction mixture was stirred at 100°C overnight. The reaction was cooled to room temperature, and the solvent was removed under vacuum. The residue was washed with MeOH (10 mL × 2) to get the imine macrocycle 5 as a yellow solid (217 mg, yield 88%).1H NMR (400 MHz, CDCl3) δ 9.20 (s, 4H), 8.09 (dd, J = 7.1, 3.3 Hz, 8H), 7.79 (s, 4H), 7.43 (dd, Attorney Docket No.11001-205WO1 J = 7.2, 3.1 Hz, 8H), 5.88 (s, 8H). MALDI-TOF m / z: [M+Na+]+Calcd for [C46H34N6Na]+693.3; found:693.7. Tetralactam macrocycle 3: A mixture of imine macrocycle 5 (200 mg, 0.298 mmol, 1 equiv.), NaClO2(647 mg, 7.16 mmol, 24 equiv.), NH4Cl (128 mg, 2.38 mmol, 8 equiv.) and α-pinene (1.9 mL, 11.9 mmol, 40 equiv.) in anhydrous THF (5 mL) was stirred at 90 ˚C for 48 h. The solvent was then removed by vacuum. The residue was washed with water (12 mL × 3), acetone (10 mL × 3) and a small amount of DMF (2 mL) to get the tetralactam macrocycle 3 as a yellow solid (130 mg, yield 59%). Mass Spectrometry Determination of thermodynamic parameters based on VT1H NMR experiments Considering the volume of the aggregate is eight times larger than that of the free macrocycle from the results of DOSY experiments, it was assumed that the aggregation is mainly in the form of octamer. Based on this assumption, equilibrium is defined as the following: 8 [BPAT2+•2Cl–]free[BPAT2+•2Cl–]8 can be expressed as the concentration of the aggregate ([BPAT2+•2Cl–]8) divided by the concentration of free molecules ([BPAT2+•2Cl–]free) raised to the power of 8: K = [BPAT2+•2Cl–]8 / [BPAT2+•2Cl–]free^8The fact that the sum of the fraction from free (X_[BPAT2+•2Cl–]free) was utilized and aggregated (X_[BPAT2+•2Cl–]8) states represents the total fraction of BPAT2+•2Cl–, which is always. Mathematically: X_[BPAT2+•2Cl–]8+ X_[BPAT2+•2Cl–]free= 1 Now, the Kaequation can be expressed in the form of relative fractions of the two components: K = X_[BPAT2+•2Cl–]8 / (X_[BPAT2+•2Cl–]free)^8 Since the free state [BPAT2+•2Cl–]freeand aggregated state [BPAT2+•2Cl–]8are in slow exchange at1H NMR time scale, the relative fractions of X_[BPAT2+•2Cl–]8 and X_[BPAT2+•2Cl–]free can be directly measured by comparing the integrations of protons e at their state, resulting in the following data listed in Table 4. Attorney Docket No.11001-205WO1 Table 4. Equilibrium parameters derived from VT NMR experiments Temperature / K Fraction [BPAT2+•2Cl–] free Fraction of [BPAT2+•2Cl–]8 lnK 308 0.175 0.825 13.8 g associated with this aggregation process: ^ ∆^ ∆^ lnK = – ^ ^ + ^ Discussion of Van’t Hoff plot analysis Thermodynamic analysis from the Van’t Hoff plot reveals an enthalpy change (∆H) of –131.8 kcal / mol and an entropy change (∆S) of –0.4 kcal / mol / K for the aggregation process. These parameters suggest that the aggregation is driven by favorable enthalpy but is offset by a significant entropy penalty. This behavior indicates that the hydrophobic effect from the stacking of anthracene panels, typically associated with an entropic benefit, cannot solely explain the aggregation mechanism. Instead, the electrostatic interactions between chloride ions and the macrocycles are essential for this distinct aggregation mechanism. The pronounced entropy penalty implies a considerable restriction in the macrocycle’s translational and conformational freedom of motion in the aggregated state. As temperature rises, particularly from 35˚C to 65˚C, the entropic penalty starts to dominate over enthalpic contributions, shifting the Gibbs free energy (∆G) from –8.6 kcal / mol to +3.4 kcal / mol and thus leading to dissociation. This observation also provides insight into why larger aggregates are not observed at higher concentrations, which would incur even more significant entropy penalties, making further aggregation thermodynamically unfavorable. Sugar Binding Analysis Using1H NMR Titration. 1H NMR titrations in D2O were conducted at 298 K on a Varian Unity Inova 400 MHz system equipped with a cryoprobe. All samples were equilibrated for 24 hours before use. Aliquots from a stock solution containing the corresponding carbohydrate were added sequentially to an NMR tube containing the solution of BPAT2+•2Cl–(600 µL). The concentration of BPAT2+•2Cl–was calibrated using imidazole as an external standard by comparing their relative integrations. The1H NMR spectrum was acquired after each addition. The1H NMR titration spectra were analyzed using MestReNova software. The NMR titration isotherms were fitted,to a 1:1 host-guest binding model using Thordarson’s equations at http: / / app.supramolecular.org / bindfit / . The data were then plotted using Attorney Docket No.11001-205WO1 OriginLab software. The binding constants Kawere presented with standard deviations from the fitting outcomes. Isothermal Titration Calorimetry Isothermal titration was performed on the MicroCal ITC200 system at 23 °C. The experiments were conducted in a titration cell with a working volume of 200 µL. The capacity of the injection syringe is 40 µL. The stirring speed was set at 750 rpm. Host and guest solutions were prepared in Milli-Q water. A stock solution of BPAT2+•2Cl–was prepared in Milli-Q water and filtrated. The concentration of BPAT2+•2Cl–was calibrated using UV-Vis absorption spectrometry. All samples were equilibrated for 24 hours before use. The host solution BPAT2+•2Cl–was placed in the titration cell, and the guests were loaded into the titration syringe. In each case, 20-25 injections were performed. The heat of dilution was measured by titrating the guest into a blank solution. The heat of dilution was subtracted before analyzing with MicroCal iTC200software using a 1:1 host-guest binding model and plotted by Origin Lab software. Circular Dichroism Spectroscopy Table 5. Circular dichroism spectra were collected using the following acquisition parameters: Measure Range 300 – 200 nm Data pitch 0.5 nm X- X-ray data and analysis for BPAT2+•2Cl–(CCDC: 2322712) X-ray diffraction data were measured on Bruker D8 Venture PHOTON II CMOS diffractometer equipped with a Cu Kα INCOATEC ImuS micro-focus source (λ = 1.54178 Å). Indexing was performed using APEX4 (Difference Vectors method). Data integration and reduction were performed using SaintPlus. Absorption correction was performed using the multi-scan method implemented in SADABS. The space group was determined using XPREP implemented in APEX3. The structure was solved using SHELXT and refined using Attorney Docket No.11001-205WO1 SHELXL-2019 / 1 (full-matrix least-squares on F2) through the OLEX2 interface program. The ellipsoid plot was made with Platon. Crystals did not diffract past ~1.3 Å resolution, and the resulting structure is of lower quality. Heavily disordered atoms were tentatively assigned as Cl- and acetone. Global RIGU and SIMU restraints were used, and restraints were used for disordered atoms. The contribution of heavily disordered solvent content in structural voids was modeled by a solvent mask implemented in Olex2. Table 6. Crystal data and structure refinement for B49. Identification code B49 Empirical formula C54H52Cl2N6O6 M i t f l C H N O 2 C H O 2 Cl 64] X-ray data and analysis for glucose ⊂BPAT2+•2Cl- complex (CCDC: 2322713) X-ray diffraction data were measured on Bruker D8 Venture PHOTON II CMOS diffractometer equipped with a Cu Kα INCOATEC ImuS micro-focus source (λ = 1.54178 Å). Indexing was performed using APEX4 (Difference Vectors method). Data integration and reduction were performed using SaintPlus. Absorption correction was performed using the multi-scan method implemented in SADABS. The space group was determined using XPREP implemented in APEX3. The structure was solved using SHELXT and refined using SHELXL-2019 / 1 (full-matrix least-squares on F2) through the OLEX2 interface program. The ellipsoid plot was made with Platon. Due to the disorder of H2O / Cl-, the assignment of Attorney Docket No.11001-205WO1 Cl63 and Cl64 to electron density was tentative. Some of the disordered atoms were refined as O (tentatively H2O). Table 7. Crystal data and structure refinement for D116. Identification code D116 Empirical formula C54H62.56Cl2N6O15.81 H2O] Atomic Forc Atomic force microscopy (AFM) imaging experiments were performed using a Bruker MultiMode 8 platform in tapping mode. A 40 μL sample of BPAT2+⋅2Cl−in water was drop-cast onto a freshly cleaved mica surface. The solution was incubated for 5 minutes to allow the deposition of the macrocycle or its aggregated nanoparticles onto the mica surface. After incubation, the sample was rapidly dried with nitrogen gas before proceeding with AFM imaging. Discussion on the results of AFM Imaging Attorney Docket No.11001-205WO1 Due to the well-known broadening effect of AFM imaging, particle dimensions in the x-y plane are not accurate (or significantly overestimated) and, therefore, not used for analyzing the particle size. Given AFM accurately measures the z dimension (e.g., the height of the particle), the heights of the particles were analyzed at different concentrations ((a) 0.02 mM, (b) 0.2 mM, and (c) 0.8 mM) and observed that higher concentrations yield larger size of the particle (or aggregate), which is consistent with the results of DOSY experiments. Computational Analysis Structural Optimization and Binding Energy Analysis The XYZ coordinates for the calculations were extracted from the X-ray single crystal data. All optimizations and single-point calculations were performed with density functional theory (DFT) in the Orca program (version 5.0.3) using the Becke ‘88 exchange and Lee- Yang-Parr correlation (BLYP) functional, the Ahlrich’s double zeta Def2-SVP basis sets with geometrical counterpoise (gCP) scheme, and Grimme’s third-generation dispersion correction with Beck Johnson damping (D3BJ). In order to speed up the DFT optimizations, the Coulomb integral and numerical chain-of-sphere integration for the HF exchanges (RIJCOSX) method was applied with the Def2 / J auxiliary basis (AuxJ). All optimizations were performed in a water continuum with the Conductor-like Polarizable Continuum Model (CPCM) in Orca. Frequency calculations of the resulting optimized structures reveal no imaginary frequency, suggesting the optimized structures were in local energy minima. Electrostatic Potential Map Single point energy calculations of BPAT2+and BPAT2+•2Cl–were performed at BLYP-SVP level. The resulting wavefunction files were used as input for calculating electron density and total electrostatic potential using the Multiwfn 3.6 program based on computerized optimized code. The results were visualized using Chimera software. Visualization of Noncovalent Interactions Independent Gradient Model (IGM) analysis is an approach to identifying and visualizing intermolecular interactions. Strong polar attractions and weak van der Waals contacts are visualized as an isosurface with blue and green colors. X-ray single crystal structures were used as input files. The binding surface was calculated by the Multiwfn 3.6 program through function 20 (visual study of weak interaction) and visualized by Chimera software. Volume Calculation Attorney Docket No.11001-205WO1 The volume of BPAT2+was calculated using MoloVol software. X-ray single crystal structure was used as input. Two spherical probes (small probe radius: 1.2 Å, large probe radius: 3 Å) were used to define cavities with a grid resolution of 0.2 Å and an optimization depth of 4. Molecular Dynamic Simulation Molecular dynamics simulations were performed using the Gromacs 2023.2 package. These simulations utilized the general AMBER force field (GAFF) for BPAT2+•2Cl–, a molecule not previously characterized in terms of force constants. As a result, the positions of the BPAT2+•2Cl–atoms were confined during the simulations. The amber99sb force field was employed for water molecules, along with the Tip4pEW explicit water model. For the BPAT2+•2Cl–, atomic charges were fitted to the Restrained Electrostatic Potential (RESP) using the Multiwfn program. This fitting was based on single-point calculations derived from crystal structure geometries. These calculations were performed using the ORCA 5.0.3 package at the BLYP / SVP level of theory. The topology file of BPAT2+•2Cl–was prepared using the Sobtop 1.0 program. The simulations were conducted in an NPT ensemble, maintaining a constant temperature of 300 K. The simulation was performed within a 4.0 nm edge-length cubic box designed to accommodate both the BPAT2+•2Cl–and the water molecules. The simulations spanned 10 nanoseconds with a time step of 1 femtosecond, following the energy minimization and equilibration of the systems. The hydration of small molecules equilibrates in the timescale of picoseconds; the simulated time of 10 ns was enough to provide a robust statistic for the host solvation. Conformer search Conformer search was performed using Conformer-Rotamer Ensemble Sampling Tool (CREST) program. X-ray single crystal structures or DFT-optimized structures were used as input for the sampling. Constrains files were first created for anthracene panels and the rest of the resides in the input files was allowed for free movement during the sampling process. The MD / MTD time step was set as 1 fs, a GBSA implicit solvation for water was used, and the sampling was performed at the SQM level of GFN2-xTB. Surface-Area Overlap (SAO) Analysis Surface-area overlap analysis was performed by Chimera and Image J software. Single crystal structures of the receptor-substrate complex were truncated by removing the top half of the receptors and visualized by Chimera. The glucose and receptors were colored to show the bridging units, the binding cavity of the receptor, the area of glucose, and the Attorney Docket No.11001-205WO1 overlapping portion between the receptor and glucose. ImageJ 1.49 software was used to measure the percent of SAO in each glucose-substrate complex. Values were calculated for the SAO-glucose (the overlapping portion between the receptor and glucose divided by the total area of the glucose). Computational analysis of the binding mechanism To uncover the underlying factors that contributed to the distinctive binding behaviors demonstrated by BPAT2+in both its free and aggregated states, density functional theory (DFT) calculations were performed at the BLYP-D3 / SVP level. The X-ray single crystal structure of glucose ⊂ BPAT2+•2Cl–was used as the starting point, optimizing this structure within a polarizable continuum solvent model in water. the calculations revealed (Fig.9a and 9b) that the energy of glucose ⊂ BPAT2+•2Cl–with both allosteric sites occupied by Cl–anions is 0.9 kcal / mol higher compared to the free macrocycle in complex with glucose (glucose ⊂ BPAT2+). The electrostatic potential maps of BPAT2+(Fig.9d) and BPAT2+•2Cl–(Fig. 9e) indicated that chloride binding at the allosteric sites neutralizes the macrocycle’s charge. This neutralization diminishes the pyridinium units’ ability to polarize the inward- facing C–H bonds, weakening hydrogen bonding strength. Moreover, the optimized structure of glucose ⊂ BPAT2+displayed a binding pattern to glucose slightly different from that observed in the solid state. In the optimized structure, one of the inward-facing C–H hydrogen bond donors is oriented (Figs. 9A-9B) towards the 4-hydroxyl group of glucose. In contrast, in the solid-state structure (Fig.9c), this C–H bond is oriented towards the 3-hydroxyl group. The variation in binding patterns results in a higher energy state by 3.1 kcal / mol (Fig.9b and 9c) when the C–H hydrogen bond donor targets the 3-hydroxyl group in the solid state. An overlay of the optimized structure of glucose ⊂ BPAT2+•2Cl–with its solid-state counterpart ([glucose ⊂ BPAT2+•2Cl–]n) demonstrates (Fig. 9f) differences in the orientation of the pyridinium units, which influence the direction of the hydrogen bond donors’ interaction with glucose. These results point to a combined effect of the macrocycle’s charge neutralization and the misorientation of the pyridinium panels in contributing to the lower affinity observed in aggregated BPAT2+•2Cl–compared to the free macrocycle. The DFT calculations suggest that the macrocycle, in its solid state, cannot achieve optimal binding with glucose. Based on this observation, it was proposed (Fig. 127A and 127B) that BPAT2+has a flexible binding pocket in its free state, where the pyridinium units are associated with a rocking motion. This structural flexibility enables the macrocycle to Attorney Docket No.11001-205WO1 adapt the direction of hydrogen bonding by reorienting the pyridinium units to accommodate the glucose’s functional group distribution. In contrast, in the aggregated state (Fig. 127B), the aromatic stacking between macrocycles freezes the pyridinium units, resulting in a rigidified binding pocket. This rigidity prevents the reorientation of the hydrogen bonding sites, leading to suboptimal binding with glucose and a consequent reduction in affinity. To test this hypothesis, constrained conformational sampling of BPAT2+was employed using the Conformer-Rotamer Ensemble Sampling Tool (CREST) program, applying constraints to the anthracene panels while allowing the pyridinium units to move freely. This approach identified ten low-energy conformers of BPAT2+. An overlay of these ten conformers (Fig. 127A) demonstrated the structural flexibility of the pyridinium units, which can oscillate without impacting the molecule’s overall low-energy state. To stimulate the aggregated state, two anthracene panels were positioned adjacent to each pyridinium unit, akin to their arrangement in the solid-state structure. While the anthracene panels were fixed, the pyridinium units were left free to move. As anticipated, this restricted setup yielded only one conformer (Fig. 127B), supporting the hypothesis that the anthracene panels froze the pyridinium units, preventing them from reorienting to optimally bind glucose. The experimental data from circular dichroism (CD) absorption spectroscopy supports the data and hypotheses above. When BPAT2+binds glucose in its free state, it induces (Fig. 12) strong CD absorption peaks between 220-270 nm. These pronounced CD signals imply that the non-chiral BPAT2+, in its free state, can adjust its conformation to bind chiral glucose, forming a well-defined chiral complex. In contrast, aggregated BPAT2+•2Cl–under identical conditions exhibits (Fig. 13) similar but significantly weaker CD signals. Notably, the strongest CD peak, occurring at 260 nm and associated with pyridinium absorption, is much less intense in the aggregated state than in the free state. This difference in peak intensity suggests that in its aggregated form, BPAT2+•2Cl–has a more rigid structure, making it less effective at forming the indued chiral complex. These results suggest that hydrogen-bonding receptors with rigid molecular skeletons may not be able to establish optimal noncovalent interactions with substrates. Instead, the incorporation of flexible hydrogen bonding residues inside the binding pocket could facilitate substrate binding. Conclusion In conclusion, the study introduces a hydrogen-bonding receptor that effectively binds sugars in water, demonstrating a remarkable binding affinity of 3001 M–1for glucose. The remarkable improvement in carbohydrate binding performance compared to a structurally Attorney Docket No.11001-205WO1 similar macrocycle underscores that carbohydrate binding is highly sensitive to slight modifications in the receptor’s structure. This insight is a valuable consideration when designing new receptors for sugars. This receptor exhibits distinctive aggregation behavior triggered by chloride binding at the allosteric sites, which, while enhancing structural rigidity, leads to reduced sugar binding affinities. These findings suggest that when designing hydrogen-bonding receptors for substrates with multiple binding sites, it is essential to balance structural flexibility with preorganization to ensure effective binding. Moreover, the synthetic lectin showcases exceptional sensitivity as a glucose sensor in various aqueous media, including water and PBS buffer, underling its potential for broad biomedical applications, from glucose-responsive devices to sensors and therapeutic agents. Other advantages which are obvious, and which are inherent to the invention, will be evident to one skilled in the art. It will be understood that certain features and sub- combinations are of utility and may be employed without reference to other features and sub- combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Claims

Attorney Docket No.11001-205WO1 CLAIMS What is claimed is:

1. A compound having the following formula: , ,R2 is H, CH3, or any combination thereof.

2. The compound of claim 1, wherein R1 is .

3. The compound of any one of claims 1-2, wherein R2 is H.

4. The compound of any one of claims 1-3, wherein the compound has the following formula:Attorney Docket No.11001-205WO1 .

5. Aa concentration of less than 25 µm.

6. A composition comprising the compound of any one of claims 1-4 at a concentration of 25 µm or more.

7. The composition of any one of claims 5-6, wherein the composition has a binding affinity to glucose of from 2800 to 3200 M-1.

8. A composition comprising the compound of any one of claims 1-4 and a sugar.

9. The composition of claim 8, wherein the sugar comprises glucose, methyl-β-glucoside, methyl-α-glucoside, mannose, galactose, psicose, fructose, cellobiose, GlcNAc, maltose, or any combination thereof.

10. The composition of any one of claims 8-9, wherein the sugar is glucose.

11. An adduct comprising the compound of any one of claims 1-4 and glucose bound thereto.

12. The adduct of claim 11, wherein the compound is bound to glucose via covalent bonding, ionic bonding, electrostatic bonding, hydrogen bonding, or any combination thereof.

13. A glucose monitor wherein the monitor comprises a receiver, a transmitter, and a sensor, wherein the sensor comprises the compound of any one of claims 1-4.

14. The glucose monitor of claim 13, wherein the sensor comprises a filament coated with the compound of any one of claims 1-4.Attorney Docket No.11001-205WO1 15. The glucose monitor of any one of claims 13-14, wherein the compound is at a concentration of less than 25 µm.

16. The glucose monitor of any one of claims 13-14, wherein the compound is at a concentration of 25 µm or more.

17. The glucose monitor of any one of claims 13-16, wherein an insulin pump is integrated with the glucose monitor.

18. A method of monitoring glucose in a subject in need thereof comprising contacting the compound of any one of claims 1-4 with a biological sample from the subject thereby resulting in a combination of the compound and the biological sample, and measuring a signal from the combination of the compound and the biological sample.

19. The method of claim 18, wherein the signal is circular dichroism (CD).

20. The method of any one of claims 18-19, wherein the subject has Type I diabetes, Type II diabetes, prediabetes, hypoglycemia, hyperglycemia, gestational diabetes, polycystic ovarian syndrome, insulin resistance, adrenal fatigue, or any combination thereof.

21. The method of any one of claims 18-20, wherein the biological sample comprises blood, interstitial fluid, or any combination thereof.

22. The method of any one of claims 18-21, wherein the glucose monitor of any one of claims is used to contact the compound with the biological sample and to measure the signal from the combination of the compound and the biological sample.

23. A method of regulating glucose in a subject in need thereof comprising monitoring glucose in accordance with any one of claims 18-22, determining the appropriate amount of insulin required by the subject in view of the signal, and administering the appropriate amount of insulin to the subject.

24. The method of claim 23, wherein the subject has Type I diabetes, Type II diabetes, prediabetes, hypoglycemia, hyperglycemia, gestational diabetes, polycystic ovarian syndrome, insulin resistance, adrenal fatigue, or any combination thereof.

25. The method of any one of claims 23-24, wherein the appropriate amount of insulin is administered to the subject subcutaneously.Attorney Docket No.11001-205WO1 26. The method of claim 25, wherein the appropriate amount of insulin is administered via a needle and syringe or via an insulin pen.

27. The method of any one of claims 23-26, wherein the appropriate amount of insulin is administered to the subject via an insulin pump.

28. The method of claim 27, wherein the insulin pump is integrated with the glucose monitor.

29. The method of any one of claims 23-28, wherein the appropriate amount of insulin is administered to the subject via an insulin inhaler.

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