Pillararene and azine assembled supramolecular sensor and its application in fluorescence colorimetric dual-channel detection of cyanide ion

Abstract

This invention discloses a supramolecular sensor assembled from columnar aromatics and azazine for dual-channel fluorescence colorimetric detection of cyanide ions. This supramolecular sensor, P5SAZ, is formed by the self-assembly of columnar aromatics and azazine derivatives. Due to the excellent supramolecular recognition properties of columnar aromatics, they can self-assemble with guest molecules into sensing materials through non-covalent interactions such as hydrogen bonding, π-π interactions, electrostatic interactions, and hydrophobic interactions. The detection of cyanide ions by azazine derivatives and the supramolecular sensor was compared. ‑ The sensitivity of the identification was tested, and the results showed that P5SAZ was sensitive to CN. ‑ It offers higher sensitivity and a lower detection limit. P5SAZ has higher sensitivity for CN. ‑ The identification mechanism is when CN ‑ Its addition causes deprotonation of the -OH group. After assembly, CN... ‑ P5SAZ exhibits affinity for CN through hydrogen bonds, anion-π interactions, and anion-dipole interactions. ‑ It has a stronger binding ability, thus improving its compatibility with CN. ‑ The sensitivity of the recognition.

Description

Technical Field

[0001] This invention relates to a supramolecular sensor assembled from columnar aromatics and azazine, and also to the dual-channel fluorescence colorimetric detection of cyanide ions by this supramolecular sensor, belonging to the fields of supramolecular materials and ion detection. Background Technology

[0002] Cyanide is highly toxic to humans and almost all other forms of life. It is commonly found in many foods and plants in nature, such as cassava, sorghum, and sprouted potatoes. Even trace amounts of cyanide can be fatal. Therefore, efficient and sensitive detection of cyanide is extremely important. Over the past few decades, methods for detecting cyanide have included ion chromatography, potentiometric methods, electrochemical methods, and titration. However, these methods suffer from high cost, long response times, and complex equipment, severely limiting their practical application. Therefore, developing a low-cost, simple, highly selective, highly sensitive, and fast-response detection method is crucial.

[0003] Currently, various ion detection methods have been developed. Fluorescence detection has become the main detection method in the field of ion detection due to its advantages of simple operation, speed, and high sensitivity. Summary of the Invention

[0004] The purpose of this invention is to provide a supramolecular sensor assembled from columnar aromatics and azazine;

[0005] Another objective of this invention is to provide a supramolecular sensor assembled from the aromatic hydrocarbon and azine for the dual-channel fluorescence colorimetric detection of cyanide ions, which, compared to the single azine derivative SAZ recognizing CN... - Improving CN through subject-object assembly - The sensitivity of the detection.

[0006] I. Supramolecular Sensors Assembled from Columnar Aromatics and Azazine

[0007] The supramolecular sensor P5SAZ of this invention has the following structural formula:

[0008]

[0009] The preparation method of supramolecular sensor assembled from columnar aromatic hydrocarbons and azazine involves adding azazine derivative SAZ and columnar aromatic hydrocarbon P5[5] in a molar ratio of 1:2 to a DMSO / H2O solution and self-assembling at room temperature to obtain supramolecular sensor P5SAZ.

[0010] The structural formula of the azine derivative SAZ is:

[0011]

[0012] The synthesis of the azine derivative SAZ is described in the following reference: Angew. Chem. Int. Ed., 2018, 57, 3163-3167.

[0013] The structural formula of column[5] aromatic P5 is:

[0014]

[0015] Synthesis of column[5] aromatic P5: J. Am. Chem. Soc., 2008, 130, 5022-5023.

[0016] II. Detection of cyanide ions using a supramolecular sensor with dual-channel fluorescence colorimetry

[0017] 1. UV and fluorescence properties of the novel supramolecular sensor P5SAZ

[0018] Studies on the ultraviolet and fluorescence properties of the supramolecular sensor P5SAZ show that, for example... Figure 1 and Figure 2 As shown, the UV fluorescence intensity of P5SAZ changed after assembly compared to both SAZ and P5, indicating that SAZ and P5 were successfully assembled.

[0019] 2. Assembly performance study of SAZ and P5

[0020] To investigate the assembly properties of compounds SAZ and P5, we used... 1 Its assembly mechanism was studied by H NMR and theoretical calculations, such as Figure 3 , 4 As shown, when a supramolecular host-guest assembly is formed, P5 penetrates into the alkyl chain of SAZ, and the alkyl chain folds. The morphology and structure before and after assembly were evaluated using scanning electron microscopy. Figure 6 It was observed that SAZ had an irregular sheet-like morphology, P5 had a blocky morphology, and after assembly, the morphology became an irregular granular morphology, indicating that SAZ and P5 were successfully assembled.

[0021] We through 1 Its assembly mechanism was studied by H NMR and theoretical calculations, such as Figure 3As shown, when a supramolecular host-guest assembly is formed, the H1 proton peak of the azazine derivative SAZ shows a slight lower field shift, while H2-H6 show a significant higher field shift, and H7-H16 show a significant lower field shift. Conversely, the Ha-Hc proton peak of P5 shows a significant higher field shift. This indicates that P5 penetrates the alkyl chain portion of the guest molecule SAZ. A CH···π interaction is formed between the benzene ring of SAZ and the -CH3 on P5, and a CH···π interaction is formed between the -CH on the SAZ alkyl chain and the benzene ring of P5. This results in a significant higher field shift of the H atoms on the benzene rings of both SAZ and P5, while H9-H16 on the SAZ alkyl chain all show significant lower field shifts. The H1 on SAZ forms a -OH···O hydrogen bond with the O on P5, causing a significant lower field shift in its H1.

[0022] After SAZ and P5 are assembled, the HOMO-LUMO orbital energy levels can be clearly observed. The HOMO of P5SAZ is mainly located on the columnar aromatic ring [5], while the LUMO is mainly distributed on the azazine structural group of compound SAZ. The HOMO-LUMO energy level difference between P5 and SAZ is greater than the band gap of P5SAZ, indicating that the emission wavelength of P5SAZ is larger than that of P5 and SAZ, respectively. The IGM diagram of SAZ and P5 assembly ( Figure 5 It can be seen that P5 penetrates into the alkyl chain of SAZ, and the alkyl chain folds. Hydrogen bonds (CH···O) are formed between the -CH group of the quaternary ammonium salt moiety of SAZ and the methoxy group on P5. CH···π interactions are formed between the -CH group on the alkyl chain and the cavity of P5, and CH···π interactions exist between the -CH group on the methoxy group and the benzene ring of SAZ. These results are consistent with those obtained by host-guest NMR. The morphology and structure before and after assembly were then evaluated by scanning electron microscopy. Figure 6 It was observed that SAZ had an irregular sheet-like morphology, P5 had a blocky morphology, and after assembly, the morphology became an irregular granular morphology, indicating that SAZ and P5 were successfully assembled.

[0023] 3. The novel supramolecular sensor P5SAZ for CN - Research on recognition performance

[0024] To investigate the effect of P5SAZ on different anions (F) in DMSO: H2O (v:v=8:2) - Cl - ,Br - I - AcO - H2PO4 - HSO4 - ClO4 - CN - SCN -N3 - S 2- To assess the detection capabilities of [the system / mechanism], we conducted a series of recognition experiments. For example... Figure 7 As shown, P5SAZ does not emit fluorescence in solution. Only CN-16 ions show fluorescence when different equimolar amounts of anions are added to P5SAZ. - It can "turn on" its fluorescence. Other anions have no effect on the fluorescence intensity of P5SAZ. Meanwhile, we found that P5SAZ in DMSO:H2O (v:v=8:2) can affect the fluorescence intensity of CN. - It can also perform "naked-eye" recognition. After adding different anions, only CN... - It can change the color of the solution from neutral to yellow, while having no effect on other ions. Figure 10 This indicates that P5SAZ in DMSO: H2O (v: v=8: 2) affects CN. - It offers good selectivity.

[0025] Subsequently, we performed a fluorescence titration experiment ( Figure 8 The detection limit was calculated to be 1.32 × 10⁻⁶ using linear fitting. -8 M ( Figure 9 The fluorescence intensity and CN of the supramolecular sensor P5SAZ - The ratio of the concentration of [Y] to the concentration of P5SAZ showed the following linear relationship: Y = 565.6 X1 / X2 - 1534.1, R 2 =0.9964; where Y is the fluorescence intensity and X1 is the CN. - X1 is the concentration of the supramolecular sensor P5SAZ, in mol / L, and X2 is the concentration of the supramolecular sensor P5SAZ, in mol / L. Since the concentration of the supramolecular sensor P5SAZ is known, substituting the measured fluorescence intensity of P5SAZ into the linear relationship allows for the quantitative detection of CN. - The concentration of [specific substance] was determined, with a detection limit of 1.32 × 10⁻⁶. - 8 M.

[0026] P5SAZ was used to calculate the effect of CN on CN through ultraviolet titration experiments and linear fitting. - The limit of detection (LOD) for ultraviolet absorption is 1.76 × 10⁻⁶. -7 M ( Figure 11 , 12 The ultraviolet absorption intensity and CN of the supramolecular sensor P5SAZ - The ratio of the concentration of [Y] to the concentration of P5SAZ showed the following linear relationship: Y = 0.034 X1 / X2 - 0.040, R 2 =0.9975; where Y is the ultraviolet absorption intensity, and X1 is the CN. -X1 is the concentration of the supramolecular sensor P5SAZ, in mol / L; X2 is the concentration of the supramolecular sensor P5SAZ, in mol / L. Since the concentration of the supramolecular sensor P5SAZ is known, substituting the measured UV absorption intensity of P5SAZ into the linear relationship allows for the quantitative detection of CN. - The concentration of [specific substance] was determined, with a detection limit of 1.76 × 10⁻⁶. -7 M.

[0027] 4. The novel supramolecular sensor P5SAZ for CN - Mechanism research of recognition

[0028] Then, we discussed the P5SAZ assembly for CN. - The mechanism of recognition. When CN - After addition, the -OH group on SAZ undergoes deprotonation. In dilute solutions, the azazine derivative SAZ exhibits intramolecular hydrogen bonds, which hinder intramolecular energy transfer, preventing it from displaying fluorescence. - The addition of CN induces a deprotonation reaction, breaking hydrogen bonds and leading to strong intramolecular charge transfer (ICT). Therefore, the addition of CN... - This allows its fluorescence to be activated.

[0029] When CN - After addition, the -OH group on SAZ undergoes deprotonation. In dilute solutions, SAZ molecules possess intramolecular hydrogen bonds, which hinder intramolecular energy transfer, preventing them from exhibiting fluorescence. - The addition of CN induces a deprotonation reaction, breaking hydrogen bonds and leading to strong intramolecular charge transfer (ICT). Therefore, the addition of CN... - This can then activate its fluorescence. For example... Figure 13 As shown, when P5SAZ and CN - After the interaction, the energy level difference between the HOMO-LUMO orbitals is greater than that between SAZ and CN. - Small. Via P5SAZ+CN - IGM diagram ( Figure 15 It can be seen that, due to the presence of weak interactions such as CH···O hydrogen bonds and CH···π after P5 assembles with SAZ, and the presence of π-rich cavities and multiple alkoxy groups in P5, CN... - The assembly can be made more responsive to CN through hydrogen bonds, anion-π interactions, anion-dipole interactions, etc. - It has a stronger binding ability, therefore, it will improve the compatibility with CN. - The sensitivity of recognition was assessed. The morphology of P5SAZ was then evaluated using scanning electron microscopy. Figure 15 P5SAZ was observed to have a blocky morphological structure, while CN... -After processing, the morphology changed to a rice-grain shape, indicating that P5SAZ and CN... - A network interaction did indeed occur between them.

[0030] 5. Novel supramolecular sensors P5SAZ and azazine derivative SAZ for CN - Comparison of the lowest detection limits

[0031] (1) The effect of azine derivative SAZ on CN - Minimum detection limit

[0032] To compare P5SAZ and SAZ against CN - Detection limits were set for SAZ versus CN. - Fluorescent titration experiment ( Figure 16 ) and UV titration experiment ( Figure 18 Then, through linear fitting, its fluorescence detection limit was calculated to be 5.75 × 10⁻⁶. -7 M ( Figure 17 The lowest detection limit for ultraviolet light is 1.1 × 10⁻⁶. -6 M ( Figure 19 ).

[0033] (2) The novel supramolecular sensor P5SAZ and SAZ for CN - Comparison of the lowest detection limits

[0034] P5SAZ against CN - Compared to SAZ, the lowest detection limit for fluorescence recognition is 5.75 × 10⁻⁶. -7 M decreased to 1.32 × 10 -8 M, the lowest detection limit for ultraviolet recognition is 1.1 × 10 -6 M decreased to 1.76 × 10 -7 M shows a significant reduction in the minimum detection limit. This demonstrates that the assembly can reduce the recognition limit of CN. - To achieve the lowest detection limit and improve sensitivity.

[0035] In summary, the assembly P5SAZ in this invention is for CN - It can perform dual-channel detection using fluorescence colorimetry, which is superior to SAZ's single-channel identification of CN. - CN - P5SAZ exhibits affinity for CN through hydrogen bonds, anion-π interactions, and anion-dipole interactions. - It has stronger integration capabilities and improves its compatibility with CN. - The sensitivity of the identification is improved, effectively reducing the minimum detection limit. This invention is for the research and development of CN in aqueous solution. - The detection of novel supramolecular fluorescent materials provides a new approach. Attached Figure Description

[0036] Figure 1 This is the ultraviolet spectrum of the P5SAZ sensor of this invention.

[0037] Figure 2 This is a fluorescence image of the P5SAZ sensor of the present invention.

[0038] Figure 3 This is the nuclear magnetic resonance spectrum of the P5SAZ sensor of this invention.

[0039] Figure 4 This is a molecular frontier orbital (HOMO-LUMO) diagram of the P5SAZ sensor of the present invention.

[0040] Figure 5 This is a diagram of the Independent Gradient Model (IGM) of the P5SAZ sensor of this invention.

[0041] Figure 6 This is a scanning electron microscope image of the P5SAZ sensor of the present invention.

[0042] Figure 7 The full fluorescence scan of the P5SAZ sensor of this invention was performed with different anions added to a DMSO / H2O (v:v=8:2) solution.

[0043] Figure 8 CN was added to the DMSO / H2O (v:v=8:2) solution of the P5SAZ sensor of this invention. - The fluorescence titration diagram.

[0044] Figure 9 CN was added to the DMSO / H2O (v:v=8:2) solution of the P5SAZ sensor of this invention. - The fluorescence titration fitting curve.

[0045] Figure 10 The UV full scan of the P5SAZ sensor of this invention was performed with different anions added to a DMSO / H2O (v:v=8:2) solution.

[0046] Figure 11 CN was added to the DMSO / H2O (v:v=8:2) solution of the P5SAZ sensor of this invention. - The ultraviolet titration diagram.

[0047] Figure 12 CN was added to the DMSO / H2O (v:v=8:2) solution of the P5SAZ sensor of this invention. - The UV titration fitting curve.

[0048] Figure 13 The sensor of this invention is P5SAZ+CN. -Molecular frontier orbital (HOMO-LUMO) diagram.

[0049] Figure 14 The sensor of this invention is P5SAZ+CN. - The Independent Gradient Model (IGM) diagram.

[0050] Figure 15 The sensor of this invention is P5SAZ+CN. - Scanning electron microscope image.

[0051] Figure 16 CN was added to the DMSO / H2O (v:v=8:2) solution of the azine derivative SAZ of this invention. - The fluorescence titration diagram.

[0052] Figure 17 CN was added to the DMSO / H2O (v:v=8:2) solution of the azine derivative SAZ of this invention. - The fluorescence titration fitting curve.

[0053] Figure 18 CN was added to the DMSO / H2O (v:v=8:2) solution of the azine derivative SAZ of this invention. - The ultraviolet titration diagram.

[0054] Figure 19 CN was added to the DMSO / H2O (v:v=8:2) solution of the azine derivative SAZ of this invention. - The UV titration fitting curve. Detailed Implementation

[0055] The following specific embodiments further illustrate the assembly of the P5SAZ sensor of the present invention and its application in the dual-channel detection of cyanide ions using fluorescence colorimetry.

[0056] Example 1: Preparation of supramolecular sensor P5SAZ

[0057] 1×10 -6 mol azine derivative SAZ and 2×10 -6 The supramolecular sensor P5SAZ can be obtained by adding aromatic P5 to a solution of DMSO / H2O (DMSO: H2O / v: v=8: 2) and self-assembling at room temperature.

[0058] Example 2: P5SAZ supramolecular sensor for CN - Study on fluorescence detection performance

[0059] Transfer 2 mL of a DMSO:H2O (v:v=8:2) solution of sensor molecule P5SAZ (C=1×10⁻⁶) to each sample.-5 M) was added to a series of colorimetric tubes, and F was added to each tube. - Cl - ,Br - I - AcO - H2PO4 - HSO4 - ClO4 - CN - SCN - N3 - S 2- If the fluorescence of the P5SAZ fluorescent sensor turns on in a DMSO / H2O solution (C=0.1M), it indicates that CN has been added. - If the fluorescence of the DMSO / H2O solution in sensor P5SAZ does not change, it indicates that CN was not added. - .

[0060] To further investigate the effect of P5SAZ on CN in DMSO / H2O - To assess the detection sensitivity, we conducted a fluorescence titration experiment. The fluorescence emission intensity of P5SAZ increased with increasing CN... - The effect gradually intensifies with increasing concentration. Based on the above results, we also plotted the corresponding fitting curve, as shown below. Figure 9 And the 3δ / S method was used to calculate the effect of P5SAZ on CN. - The limit of detection (LOD) for fluorescence is 1.32 × 10⁻⁶. -8 M.

[0061] Example 3: P5SAZ supramolecular sensor for CN - Study on ultraviolet detection performance

[0062] Transfer 2 mL of a DMSO:H2O (v:v=8:2) solution of sensor molecule P5SAZ (C=1×10⁻⁶) to each sample. -5 M) was added to a series of colorimetric tubes, and F was added to each tube. - Cl - ,Br - I - AcO - H2PO4 - HSO4 - ClO4 - CN - SCN - N3 - S 2- If the DMSO / H2O solution of the P5SAZ fluorescence sensor turns yellow, it indicates that CN has been added, and the solution contains 0.1M (C=0.1M). -If the color of the DMSO / H2O solution in sensor P5SAZ does not change, it indicates that CN was not added. - .

[0063] To further investigate the effect of P5SAZ on CN in DMSO-H2O - To assess the sensitivity of "naked-eye" recognition, we conducted a UV titration experiment. The UV absorption intensity of P5SAZ increased with CN... - The effect gradually intensifies with increasing concentration. Based on the above results, we also plotted the corresponding fitting curve, as shown below. Figure 12 Calculate SAZ against CN - The limit of detection (LOD) for ultraviolet absorption is 1.76 × 10⁻⁶. -7 M.

Claims

1. A supramolecular sensor of pillararene and azine assembly, having a structural formula as follows: 。 2. The method for preparing a pillararene and azine assembled supramolecular sensor according to claim 1, characterized in that: The azine derivative and the pillar[5]arene are added into a DMSO / H2O solution at a molar ratio of 1:2, and self-assembled at room temperature to obtain the supramolecular sensor P5SAZ; the DMSO / H2O solution has a volume ratio of DMSO to H2O of 8:2; The azine derivative SAZ has a structural formula as follows: The pillar[5]arene P5 has a structural formula as follows: 。 3.The supramolecular sensor of claim 1, applied to fluorescence detection of cyanide ions.

4. Use of the pillararene and azine assembled supramolecular sensor according to claim 3 for the fluorescence detection of cyanide ions, characterized in that: In DMSO / H2O solution of supramolecular sensor P5SAZ, the aqueous solution of F - , Cl - , Br - , I - , AcO - , H2PO4 - , HSO4 - , ClO4 - , CN - , SCN - , N3 - , S 2- was added respectively, only the addition of CN - can make the fluorescence of supramolecular sensor open; in DMSO / H2O solution, the volume ratio of DMSO and H2O is 8:

2.

5. Use of the pillararene and azine assembled supramolecular sensor according to claim 1 for the quantitative detection of cyanide ions, characterized in that: The ratio of the fluorescence intensity of supramolecular sensor P5SAZ and the concentration of CN - has the following linear relationship: Y=565.6 X1 / X2-1534.1, R 2 =0.9964; wherein Y is the fluorescence intensity, X1 is the concentration of CN - , unit: mol / L, X2 is the concentration of supramolecular sensor P5SAZ, unit: mol / L; the fluorescence intensity of supramolecular sensor P5SAZ determined is substituted into the linear relationship to quantitatively detect the concentration of CN - , and the lowest detection limit is 1.32×10 -8 M. 6.The supramolecular sensor of claim 1, applied to colorimetric detection of cyanide ions.

7. Use of the pillararene and azine assembled supramolecular sensor according to claim 6 for the colorimetric detection of cyanide ions, characterized in that: In DMSO / H2O solution of supramolecular sensor P5SAZ, the aqueous solution of F - , Cl - , Br - , I - , AcO - , H2PO4 - , HSO4 - , ClO4 - , CN - , SCN - , N3 - , S 2- was added respectively, only the addition of CN - could make the color of the supramolecular sensor solution change from colorless to light yellow; in DMSO / H2O solution, the volume ratio of DMSO to H2O was 4:

1.

8. Use of the pillararene and azine assembled supramolecular sensor according to claim 1 for the quantitative detection of cyanide ions, characterized in that: UV absorption intensity and CN of supramolecular sensor P5SAZ - The ratio of the concentration of [Y] to the concentration of P5SAZ showed the following linear relationship: Y = 0.034 X1 / X2 - 0.040, R 2 =0.9975; where Y is the ultraviolet absorption intensity, and X1 is the CN. - X1 is the concentration of the supramolecular sensor P5SAZ, in mol / L; X2 is the concentration of the supramolecular sensor P5SAZ, in mol / L. Substituting the measured UV absorption intensity of the supramolecular sensor P5SAZ into the linear relationship allows for the quantitative detection of CN. - The concentration of [specific substance] was determined, with a detection limit of 1.76 × 10⁻⁶. -7 M.

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