Construction of acylhydrazone-based sensing material for dimensional regulation of conformational domains and detection of synthetic cannabinoid fub-inaca

Abstract

This invention provides a dimensionally regulated conformationally confined acylhydrazone sensing material for the construction of a synthetic cannabinoid FUB-INACA and its detection. The acylhydrazone sensing material uses 1H-imidazolium-4,5-dicarboxyhydrazide and triphenylamine derivatives with different numbers of substituent aldehyde groups as basic building blocks. By controlling the feed ratio and reaction conditions, acylhydrazone sensing materials with different dimensions are gradually constructed. As the material evolves from a zero-dimensional discrete molecule to a one-dimensional linear polymer and then to a two-dimensional covalent organic framework, the conformational freedom of the acylhydrazone sensing material gradually decreases, accompanied by a gradual decrease in intrinsic background fluorescence. This achieves high signal-to-noise ratio and quantitative detection of the synthetic cannabinoid FUB-INACA, exhibiting advantages such as fast response speed (<1 s), low detection limit (1.3 nM), and excellent selectivity.

Description

Technical Field

[0001] This invention relates to the fields of organic functional materials and drug detection, and provides a method for constructing acylhydrazone sensing materials with dimensionally modulated conformational confinement and for detecting the synthetic cannabinoid FUB-INACA. Background Technology

[0002] Fluorescent molecular recognition technology, with its advantages of high sensitivity, ease of operation, and real-time response, has become an indispensable analytical tool in the fields of chemical sensing, biological analysis, and forensic evidence identification. In practical detection applications, especially in scenarios with complex chemical compositions, the reliability of the analytical method depends not only on the absolute emission intensity of the fluorescence signal but also on the signal-to-noise ratio achievable by the detection system.

[0003] Currently, research on improving the performance of fluorescence sensors largely focuses on signal amplification strategies, such as increasing the quantum yield of materials (Advanced Functional Materials 2025, 35, 2425759), introducing aggregation-induced emission (AIE) units (Journal of the American Chemical Society 2026, 148, 3167-3173), and constructing energy transfer pathways. However, the intrinsic background emission of the sensing material is generally overlooked as a key limiting factor. Continuous intrinsic background fluorescence of the sensing material can mask weak signal changes induced by the target analyte, directly reducing detection fidelity and ultimately limiting the improvement of detection sensitivity. Therefore, compared to simply amplifying the signal output, fundamentally suppressing background emission is a more effective and groundbreaking technical approach to achieving high signal-to-noise ratio fluorescence recognition, but relevant systematic solutions are still relatively scarce in existing technologies.

[0004] At the molecular level, fluorescence behavior is closely related to molecular conformational dynamics. Intramolecular rotation, bond twisting, and structural flexibility (Angewandte Chemie International Edition 2025, 64, e16124) introduce non-radiative decay pathways, dissipate excited-state energy, and thus regulate the luminescence behavior of materials. Although the industry has gradually recognized the influence of conformational effects on the photophysical processes of materials, most existing conformational regulation strategies are limited to single-molecule modification or local structure locking, and a generalized platform that can achieve cross-level structural dimensions and progressively regulate conformational freedom has not yet been developed. Extending conformational regulation from discrete small molecule systems to linear polymers and framework materials systems can achieve systematic regulation of the intrinsic luminescence properties of materials and establish a clear structure-conformation-signal-noise ratio structure-activity relationship. This dimension-driven conformational regulation strategy can upgrade conformational regulation from a molecular-level phenomenon to a universal design principle for high-fidelity fluorescence recognition systems. However, there is currently a lack of systematic research on the influence of different dimensional structural systems on the intrinsic luminescence properties and target response behavior of materials.

[0005] This invention focuses on the research of novel psychoactive substances, synthetic cannabinoids. Using 1H-imidazolium-4,5-dicarboxyhydrazide (IDA) and triphenylamine derivatives as basic building blocks, an acylhydrazone-based sensing material was gradually constructed by controlling the feed ratio and polymerization conditions. The material progressed from the zero-dimensional discrete molecule DPA-IDA to the one-dimensional linear polymer DFTA-IDA and then to the two-dimensional covalent organic framework TFPA-IDA COFs. By dimensionally inducing molecular conformational confinement, background fluorescence was reduced, thereby achieving highly sensitive, high signal-to-noise ratio, and high specificity recognition of the synthetic cannabinoid FUB-INACA. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of traditional sensing materials, such as high intrinsic background fluorescence, low signal-to-noise ratio, and weak anti-interference ability, by providing a dimensionally modulated conformationally confined acylhydrazone sensing material and its application in the detection of the synthetic cannabinoid FUB-INACA. This material uses 1H-imidazolium-4,5-dicarboxyhydrazide (IDA) as a fixed reactant monomer, and reacts with triphenylamine derivatives with different numbers of aldehyde substituents as reactants. Acylhydrazone sensing materials with different dimensional structures are synthesized via a solvothermal method, and the background fluorescence gradually decreases with increasing dimensionality. When used for the detection of synthetic cannabinoid FUB-INACA, the three sensing materials with different dimensions exhibit significantly different fluorescence response behaviors. The two-dimensional covalent organic framework sensing material possesses high signal-to-noise ratio, high sensitivity, and high selectivity, and shows no response to other common structural and property analogs and sample coexisting matrices, enabling quantitative and real-time detection of synthetic cannabinoid FUB-INACA.

[0007] The present invention discloses a dimensionally modulated conformationally confined acylhydrazone-based sensing material, the general structural formula of which is:

[0008] Where R a =R b =R a '=R b When '=H, it corresponds to a zero-dimensional discrete molecule; When R a =R a '=H,R b =R b '= At that time, it corresponds to a one-dimensional linear polymer; When R a =R b =R a '=R b '= At that time, it corresponds to two-dimensional covalent organic framework materials; Structure and endogenous luminescence of three acylhydrazone-based sensing materials: Zero-dimensional discrete molecule: It exhibits a quasi-linear conformation in structure, with a nitrogen-nitrogen distance of 19.3 Å between the two triphenylamine units and a bond angle of 135.5° relative to the central imidazole nucleus. It exhibits the strongest fluorescence emission, with the emission peak centered at 480 nm. One-dimensional linear polymer: Structurally, its model is constructed by the bilayer stacking of repeating units, with a characteristic interlayer spacing of 4.6 Å and an intermolecular cross-shift of 7.8 Å; In terms of luminescence properties, compared with zero-dimensional discrete molecules, the emission peak is redshifted by 50 nm, and the luminescence intensity shows a dramatic decrease of up to 50%. Two-dimensional covalent organic framework: It exhibits a significant curved conformation in structure, with an NN distance of 13.1 Å between the two triphenylamine units at its two ends and a bond angle of 88.6° relative to the central imidazole nucleus. Its intrinsic fluorescence emission is almost negligible.

[0009] The preparation method of the dimensionally modulated conformationally confined acylhydrazone-based sensing material is carried out according to the following steps: Zero-dimensional discrete molecules and one-dimensional linear polymers: a. 1H-imidazolium-4,5-dicarboxyhydrazide with a concentration of 4.6 mg / mL was ultrasonically dissolved in methanol with 4-(diphenylamino)benzaldehyde and 4,4'-(phenylazinediyl)dibenzaldehyde at mass ratios of 1:3 and 1:1.6, respectively. Then, 1 drop of glacial acetic acid was added, and the mixture was stirred and mixed evenly. The mixture was then transferred to a 50 mL round-bottom flask to obtain the reaction solution. b. The reaction solution obtained in step a is heated to 70℃ and refluxed under continuous magnetic stirring for 4-6 hours. After cooling to room temperature, the target product is obtained by filtration. After further purification by recrystallization in methanol, it is dried in a vacuum oven at 50℃ for 12 hours to obtain the light green zero-dimensional discrete molecule N'4,N'5-bis((E)-4-(diphenylamino)benzylidene)-1H-imidazolium-4,5-dicarboxyhydrazide; and the bright yellow one-dimensional linear polymer N'4-ethylene-N'5-((E)-4-((4-((1E)-(2-(5-(2-ethylenehydrazine-1-carbonyl)-1H-imidazolium-4-carbonyl)hydrazine)methyl)phenyl)(phenyl)amino)benzylidene)-1H-imidazolium-4,5-dicarboxyhydrazide; Two-dimensional covalent organic framework materials: c. Dissolve tris(4-formylphenyl)amine and 1H-imidazolium-4,5-dicarboxyhydrazide at a mass ratio of 1.9:1 in a toluene / trimethylbenzene mixed solvent at a volume ratio of 2:1 using ultrasonication. Then add 0.04 volume equivalents of acetic acid aqueous solution with a concentration of 3 mol / L and 0.001 volume equivalents of aniline solution. After mixing thoroughly, transfer the solution to a 10 mL heat-resistant glass tube. d. After the heat-resistant glass tube was degassed by three consecutive cycles of freezing-vacuuming-thawing, it was sealed under high vacuum and placed in an oven at a constant temperature of 120℃ for 72 hours. After cooling to room temperature, it was filtered to obtain a pale yellow precipitate, which was then washed three times in sequence with tetrahydrofuran, acetone, dimethyl sulfoxide, and methanol. The product was then dried in a vacuum oven at 80℃ for 12 hours to obtain the target product, an acylhydrazone covalent organic framework.

[0010] The method for detecting the synthetic cannabinoid FUB-INACA using a dimensionally modulated conformationally confined acylhydrazone sensing material is performed according to the following steps: Detection of synthetic cannabinoids FUB-INACA using acylhydrazone sensing materials: a. The obtained zero-dimensional discrete molecules, one-dimensional linear polymers or two-dimensional covalent organic framework materials are ultrasonically dispersed in methanol to prepare an acylhydrazone-based sensing material detection reagent with a concentration of 0.045 mg / mL, and the detection reagent is packaged in a brown reagent bottle; Quantitative detection of synthetic cannabinoids using FUB-INACA solution: b. Dissolve the synthetic cannabinoid FUB-INACA in methanol solution to obtain a synthetic cannabinoid FUB-INACA standard solution with a concentration of 0 μmol / L-1000 μmol / L. c. Add the synthetic cannabinoid FUB-INACA standard solution with a concentration of 0 μmol / L to 1000 μmol / L obtained in step b to the acylhydrazone-based sensing material detection reagent obtained in step a. The volume ratio of the acylhydrazone-based sensing material detection reagent to the synthetic cannabinoid FUB-INACA standard solution is 4:1. Under 395 nm excitation light, the fluorescence spectrum is measured. As the concentration of synthetic cannabinoid FUB-INACA increases, the zero-dimensional discrete molecule and the one-dimensional linear polymer show the characteristics of decreased fluorescence and increased fluorescence, respectively. The fluorescence emission peak of the two-dimensional covalent organic framework at 526 nm gradually increases, and the fluorescence color changes from colorless to green. The response time is less than 1 s. There is no response to other synthetic cannabinoids and traditional drugs. d. The fluorescence intensity at 526 nm was linearly fitted with the concentration of synthetic cannabinoid FUB-INACA to obtain a standard curve, which was used for the quantitative analysis of synthetic cannabinoid FUB-INACA in unknown samples.

[0011] This invention discloses the construction of a dimension-controlled conformationally confined acylhydrazone sensing material and its application in the detection of the synthetic cannabinoid FUB-INACA. The method is based on a sensing mechanism that uses dimension-induced conformational freedom to regulate intrinsic fluorescence and multi-action synergistic specific recognition, as detailed below: Fluorescence emission occurs between the imidazole and imine bonds in the zero-dimensional discrete molecule DPA-IDA and the one-dimensional linear polymer DFTA-IDA due to the excited-state intramolecular proton transfer (ESIPT) process. In the two-dimensional covalent organic framework TFPA-IDA COFs, the excited-state intramolecular proton transfer (ESIPT) process is suppressed due to conformational inhibition, resulting in negligible intrinsic background fluorescence. When the synthetic cannabinoid FUB-INACA is added to the system, its negative potential point can efficiently bind with the strongly positive potential points of the acylhydrazine and imidazole ring regions in the sensing material. Through hydrogen bonding, π-π stacking, van der Waals forces, and hydrophobic effects, a stable complex is formed, breaking the original intramolecular interactions and activating the intramolecular charge transfer (ICT) process, significantly improving the radiative transition efficiency. The fluorescence of the zero-dimensional discrete molecule DPA-IDA decreases by 18.93%, while the fluorescence of the one-dimensional linear polymer DFTA-IDA increases by 66.12%, and the fluorescence of the two-dimensional covalent organic framework TFPA-IDA increases significantly. COFs transition from almost no fluorescence to bright green fluorescence, enabling high signal-to-noise ratio and high specificity detection of FUB-INACA.

[0012] Compared with the prior art, the beneficial effects of the present invention are: The dimensionally modulated conformationally confined acylhydrazone sensing material prepared by this invention controls the dimensionality and conformational degrees of freedom of the sensing material by adjusting the number of aldehyde substituents in the triphenylamine derivative, thereby suppressing the background fluorescence of the sensing material. This clarifies the relationship between the dimensionality, conformational degrees of freedom, luminescence properties of the sensing material and its sensing properties for the target substance, and achieves highly sensitive, high signal-to-noise ratio, rapid, specific, and quantitative fluorescence detection of the synthetic cannabinoid FUB-INACA, effectively overcoming the shortcomings of existing technologies. Attached Figure Description

[0013] Figure 1 The theoretical calculation simulation structure diagrams of the three different dimensional acylhydrazone sensing materials of the present invention are shown. They correspond to different dimensional structures obtained by controlling the number of triphenylamine aldehyde groups, respectively. The spatial configuration differences of the three materials are clearly shown, and the control effect of the number of triphenylamine aldehyde groups on the material dimension is intuitively reflected. Figure 2 The fluorescence spectra of the present invention are shown in 100 μL of methanol dispersion of three different acylhydrazone sensing materials with a concentration of 0.036 mg / mL and after the addition of 20 μL of 100 μmol / L synthetic cannabinoid FUB-INACA. Figure 3 The present invention involves adding 20 μL of synthetic cannabinoid FUB-INACA standard solution of 0 μmol / L to a dispersion of two-dimensional acylhydrazone covalent organic framework material with a concentration of 0.045 mg / mL, and then measuring the fluorescence spectrum after the reaction. Figure 4 The present invention is based on the reaction of 20 μL of synthetic cannabinoid FUB-INACA standard solution with concentrations of 0-1000 μmol / L to 80 μL of acylhydrazone covalent organic framework material dispersion, and the fluorescence peak intensity at 526 nm as a function of FUB-INACA methanol solution concentration. Figure 5 The present invention describes the reaction curves of fluorescence peak intensity at 526 nm versus reaction time after adding 20 μL of synthetic cannabinoid FUB-INACA standard solution with concentrations of 0 μmol / L to 1000 μmol / L to 80 μL of acylhydrazone covalent organic framework material dispersion. Figure 6To facilitate this invention, 20 μL of a 100 μmol / L synthetic cannabinoid FUB-INACA standard solution was added to 80 μL of an acylhydrazone covalent organic framework material dispersion with a concentration of 0.045 mg / mL. 20 μL of the following substances were added to 80 μL of a probe solution with a concentration of 0.045 mg / mL: JWH-073, AM-2201, SDB-006, EG-2201, THJ-2201, naphthalene, barbiturate, phenobarbital (PB), fentanyl, heroin, methamphetamine (MA, crystal meth), methcathinone (MCAT), morphine (Mor), ketamine (K powder), methadone (MTD), tryptamine (TA), sodium chloride (NaCl), potassium chloride (KCl), potassium sorbate (PS), acesulfame K, and 1,2- Fluorescence spectra of propylene glycol (1,2-PDO) and glycerol (Gly) in methanol solution after reaction. Detailed Implementation

[0014] The present invention will be further described below through specific embodiments, but the invention is not limited to these embodiments. Example 1

[0015] Zero-dimensional discrete molecules and one-dimensional linear polymers: a. 1H-imidazolium-4,5-dicarboxyhydrazide with a concentration of 4.6 mg / mL was ultrasonically dissolved in methanol with 4-(diphenylamino)benzaldehyde and 4,4'-(phenylazinediyl)dibenzaldehyde at mass ratios of 1:3 and 1:1.6, respectively. Then, 1 drop of glacial acetic acid was added, and the mixture was stirred and mixed evenly. The mixture was then transferred to a 50 mL round-bottom flask to obtain the reaction solution. b. The reaction solution obtained in step a is heated to 70℃ and refluxed under continuous magnetic stirring for 4-6 hours. After cooling to room temperature, the target product is obtained by filtration. After further purification by recrystallization in methanol, it is dried in a vacuum oven at 50℃ for 12 hours to obtain the light green zero-dimensional discrete molecule N'4,N'5-bis((E)-4-(diphenylamino)benzylidene)-1H-imidazolium-4,5-dicarboxyhydrazide; and the bright yellow one-dimensional linear polymer N'4-ethylene-N'5-((E)-4-((4-((1E)-(2-(5-(2-ethylenehydrazine-1-carbonyl)-1H-imidazolium-4-carbonyl)hydrazine)methyl)phenyl)(phenyl)amino)benzylidene)-1H-imidazolium-4,5-dicarboxyhydrazide; Two-dimensional covalent organic framework materials: c. Dissolve tris(4-formylphenyl)amine and 1H-imidazolium-4,5-dicarboxyhydrazide at a mass ratio of 1.9:1 in a toluene / trimethylbenzene mixed solvent at a volume ratio of 2:1 using ultrasonication. Then add 0.04 volume equivalents of acetic acid aqueous solution with a concentration of 3 mol / L and 0.001 volume equivalents of aniline solution. After mixing thoroughly, transfer the solution to a 10 mL heat-resistant glass tube. d. After the heat-resistant glass tube was degassed by three consecutive cycles of freezing-vacuuming-thawing, it was sealed under high vacuum and placed in an oven at a constant temperature of 120℃ for 72 hours. After cooling to room temperature, it was filtered to obtain a pale yellow precipitate. The precipitate was then washed three times in sequence with tetrahydrofuran, acetone, dimethyl sulfoxide, and methanol. The product was then dried in a vacuum oven at 80℃ for 12 hours to obtain the target product, acylhydrazone covalent organic framework. The structural characteristics and endogenous luminescence properties of the three acylhydrazone-based sensing materials are as follows: Figure 1 , 2 : Zero-dimensional discrete molecule DPA-IDA: It exhibits a quasi-linear conformation in structure. The nitrogen-nitrogen (NN) distance between the two ends of the triphenylamine (TPA) moiety is 19.3 Å, and the bond angle relative to the central imidazole nucleus is 135.5°. It exhibits the strongest fluorescence emission, with the center of the emission peak located at 480 nm. One-dimensional linear polymer DFTA-IDA: Structurally, its model is constructed by the bilayer stacking of repeating units, with a characteristic interlayer spacing of 4.6 Å and an intermolecular cross-shift of 7.8 Å; In terms of luminescence properties, compared with the zero-dimensional discrete molecule DPA-IDA, the emission peak is redshifted by 50 nm, and the luminescence intensity shows a drastic decrease of up to 50%. Two-dimensional covalent organic frameworks TFPA-IDA COFs exhibit a significant bent conformation, with an NN distance of 13.1 Å between the two triphenylamine units and a bond angle of 88.6° relative to the central imidazole nucleus. Their intrinsic fluorescence emission is almost negligible. Example 2

[0016] Preparation of zero-dimensional discrete molecular DPA-IDA detection reagent: The zero-dimensional discrete molecular DPA-IDA obtained in Example 1 was ultrasonically dispersed in methanol to prepare a zero-dimensional discrete molecular DPA-IDA detection reagent with a concentration of 0.045 mg / mL, and the detection reagent was packaged in a brown reagent bottle; Quantitative detection method of synthetic cannabinoids using FUB-INACA solution: The synthetic cannabinoid FUB-INACA was dissolved in methanol to obtain a standard solution of synthetic cannabinoid FUB-INACA with a concentration of 100 μmol / L. The obtained zero-dimensional discrete molecular DPA-IDA detection reagent was mixed with a 100 μmol / L synthetic cannabinoid FUB-INACA standard solution, with a volume ratio of 4:1. Fluorescence spectra were measured under 395 nm excitation light. With the addition of synthetic cannabinoid FUB-INACA, the fluorescence emission peak of zero-dimensional discrete molecular DPA-IDA at 480 nm showed a decrease in fluorescence intensity (e.g., ...). Figure 2 (As shown). Example 3

[0017] Quantitative detection method of synthetic cannabinoids using FUB-INACA solution: The synthetic cannabinoid FUB-INACA was dissolved in methanol to obtain a standard solution of synthetic cannabinoid FUB-INACA with a concentration of 500 μmol / L. The obtained zero-dimensional discrete molecular DPA-IDA detection reagent was mixed with a synthetic cannabinoid FUB-INACA standard solution with a concentration of 500 μmol / L. The volume ratio of the zero-dimensional discrete molecular DPA-IDA detection reagent to the synthetic cannabinoid FUB-INACA standard solution was 4:1. The fluorescence spectrum was measured under 395 nm excitation light. With the addition of synthetic cannabinoid FUB-INACA, the fluorescence emission peak of zero-dimensional discrete molecular DPA-IDA at 480 nm showed a decrease in fluorescence. Example 4

[0018] Preparation of one-dimensional linear polymer DFTA-IDA detection reagent: The one-dimensional linear polymer DFTA-IDA obtained in Example 1 was ultrasonically dispersed in methanol to prepare a one-dimensional linear polymer DFTA-IDA detection reagent with a concentration of 0.045 mg / mL, and the detection reagent was packaged in a brown reagent bottle; Quantitative detection method of synthetic cannabinoids using FUB-INACA solution: The synthetic cannabinoid FUB-INACA was dissolved in methanol to obtain a standard solution of synthetic cannabinoid FUB-INACA with a concentration of 100 μmol / L. The obtained one-dimensional linear polymer DFTA-IDA detection reagent was mixed with a 100 μmol / L synthetic cannabinoid FUB-INACA standard solution, with a volume ratio of 4:1. Fluorescence spectra were measured under 395 nm excitation light. With the addition of synthetic cannabinoid FUB-INACA, the fluorescence emission peak of the one-dimensional linear polymer DFTA-IDA at 530 nm showed a decrease in fluorescence intensity (e.g., ...). Figure 2 (As shown). Example 5

[0019] Quantitative detection method of synthetic cannabinoids using FUB-INACA solution: The synthetic cannabinoid FUB-INACA was dissolved in methanol to obtain a standard solution of synthetic cannabinoid FUB-INACA with a concentration of 500 μmol / L. The obtained one-dimensional linear polymer DFTA-IDA detection reagent was mixed with a synthetic cannabinoid FUB-INACA standard solution at a concentration of 500 μmol / L, with a volume ratio of 4:1. Fluorescence spectra were measured under 395 nm excitation light. With the addition of synthetic cannabinoid FUB-INACA, the fluorescence emission peak of the one-dimensional linear polymer DFTA-IDA at 530 nm showed a decrease in fluorescence intensity (e.g., ...). Figure 2 (As shown). Example 6

[0020] Preparation of TFPA-IDA COFs detection reagent for two-dimensional covalent organic frameworks: The two-dimensional covalent organic framework TFPA-IDA COFs obtained in Example 1 were ultrasonically dispersed in methanol to prepare a two-dimensional covalent organic framework TFPA-IDA COFs detection reagent with a concentration of 0.045 mg / mL, and the detection reagent was packaged in a brown reagent bottle; Quantitative detection method of synthetic cannabinoids using FUB-INACA solution: The synthetic cannabinoid FUB-INACA was dissolved in methanol to obtain standard solutions of synthetic cannabinoid FUB-INACA with concentrations of 5, 10, 25, 50, 75, 100, 125, 150, 200, 250, 375, 500, and 1000 μmol / L. The obtained two-dimensional covalent organic framework TFPA-IDA COFs detection reagent was mixed with synthetic cannabinoid FUB-INACA standard solutions at concentrations of 5, 10, 25, 50, 75, 100, 125, 150, 200, 250, 375, 500, and 1000 μmol / L, respectively. The volume ratio of the two-dimensional covalent organic framework TFPA-IDA COFs detection reagent to the synthetic cannabinoid FUB-INACA standard solution was 4:1. Fluorescence spectra were measured under 395 nm excitation light. With increasing concentration of synthetic cannabinoid FUB-INACA, the fluorescence emission peak of the two-dimensional covalent organic framework TFPA-IDA COFs at 526 nm gradually increased (e.g., ...). Figure 2 , 3 (As shown). Example 7

[0021] Linear relationship between fluorescence intensity at 526 nm and concentration of synthetic cannabinoid FUB-INACA after reaction of TFPA-IDA COFs detection reagent with synthetic cannabinoid FUB-INACA solution: Take 80 μL of the TFPA-IDA COFs detection reagent and 20 μL of methanol solutions of synthetic cannabinoid FUB-INACA at concentrations of 5, 10, 25, 50, 75, 100, 125, 150, 200, 250, 375, 500, and 1000 μmol / L, and add them to the TFPA-IDA COFs detection reagent. After the reaction, perform fluorescence spectroscopy testing. Plot a standard graph using the fluorescence emission intensity of the solution at 526 nm and the concentration of synthetic cannabinoid FUB-INACA. Based on the standard fluorescence spectrum graph (e.g., ...), ... Figure 4 As shown in the figure, it can be seen that with the increase of the concentration of synthetic cannabinoid FUB-INACA, the fluorescence emission intensity at 526 nm shows a good linear relationship. The detection limit calculated using the formula LOD=3σ / K (K=1877342,σ=8.04) is 1.3 nM. Example 8

[0022] Response time of TFPA-IDA COFs detection reagent and synthetic cannabinoid FUB-INACA solution: Take 80 μL of the two-dimensional covalent organic framework TFPA-IDA COFs detection reagent, and then add 20 μL of a 100 mmol / L synthetic cannabinoid FUB-INACA solution. Plot a scatter plot of the fluorescence emission intensity of the solution at 526 nm versus the reaction time. Figure 5 As shown, the response time is less than 1 second. Example 9

[0023] Specific detection and identification of two-dimensional covalent organic frameworks (TFPA-IDA) COFs and synthetic cannabinoids (FUB-INACA) solutions: Take 80 μL of TFPA-IDA COFs sensing material reagent, and then add 20 μL of solutions of the following synthetic cannabinoids at a concentration of 100 mmol / L: FUB-INACA, JWH-073, AM-2201, SDB-006, EG-2201, THJ-2201, naphthalene, barbiturate, phenobarbital (PB), fentanyl, heroin, methamphetamine (MA, crystal meth), methcathinone (MCAT), morphine (Mor), ketamine (K powder), methadone (MTD), tryptamine (TA), sodium chloride (NaCl), potassium chloride (KCl), potassium sorbate (PS), acesulfame K, 1,2-propanediol (1,2-PDO), and glycerol (Gly). After the reaction, perform fluorescence spectroscopy testing. Figure 6 As shown, a fluorescence emission peak at 526 nm only appeared when the synthetic cannabinoid FUB-INACA solution was added, while almost no fluorescence change was observed when other common interfering substances were added, indicating that the two-dimensional covalent organic framework TFPA-IDA COFs material has good specificity for the detection of synthetic cannabinoid FUB-INACA.

[0024] Example 10 (Comparative) Methanol solutions were added to the obtained acylhydrazone-based sensing materials, namely zero-dimensional discrete molecules DPA-IDA, one-dimensional linear polymers DFTA-IDA, or two-dimensional covalent organic frameworks TFPA-IDA COFs detection reagents. The volume ratio of the acylhydrazone-based sensing material detection reagent to the synthetic cannabinoid FUB-INACA standard solution was 4:1. Fluorescence spectra were measured under 395 nm excitation light. The zero-dimensional discrete molecule DPA-IDA showed the strongest fluorescence intensity at 480 nm. The fluorescence intensity of the one-dimensional linear polymer DFTA-IDA at 530 nm decreased by 50% compared to the zero-dimensional discrete molecule DPA-IDA. The fluorescence of the two-dimensional covalent organic framework TFPA-IDA COFs at 526 nm was almost negligible (e.g., ...). Figure 2 (As shown).

Claims

1. A dimensionally modulated conformationally confined acylhydrazone-based sensing material, characterized in that, The general structural formula of this material is: Where R a =R b =R a '=R b When '=H, it corresponds to a zero-dimensional discrete molecule; When R a =R a '=H,R b =R b '= At that time, it corresponds to a one-dimensional linear polymer; When R a =R b =R a '=R b '= At that time, it corresponds to two-dimensional covalent organic framework materials; Structure and endogenous luminescence of three acylhydrazone-based sensing materials: Zero-dimensional discrete molecule: It exhibits a quasi-linear conformation in structure, with a nitrogen-nitrogen distance of 19.3 Å between the two triphenylamine units and a bond angle of 135.5° relative to the central imidazole nucleus. It exhibits the strongest fluorescence emission, with the emission peak centered at 480 nm. One-dimensional linear polymer: Structurally, its model is constructed by the bilayer stacking of repeating units, with a characteristic interlayer spacing of 4.6 Å and an intermolecular cross-shift of 7.8 Å; in terms of luminescence properties, compared with zero-dimensional discrete molecules, the emission peak is redshifted by 50 nm, and the luminescence intensity shows a dramatic decrease of up to 50%. Two-dimensional covalent organic framework: It exhibits a significant curved conformation in structure, with an NN distance of 13.1 Å between the two triphenylamine units at its two ends and a bond angle of 88.6° relative to the central imidazole nucleus. Its intrinsic fluorescence emission is almost negligible.

2. The construction of a dimensionally modulated conformationally confined acylhydrazone-based sensing material as described in claim 1, characterized in that, Follow these steps: Zero-dimensional discrete molecules and one-dimensional linear polymers: a. 1H-imidazolium-4,5-dicarboxyhydrazide with a concentration of 4.6 mg / mL was ultrasonically dissolved in methanol with 4-(diphenylamino)benzaldehyde and 4,4'-(phenylazinediyl)dibenzaldehyde at mass ratios of 1:3 and 1:1.6, respectively. Then, 1 drop of glacial acetic acid was added, and the mixture was stirred and mixed evenly. The mixture was then transferred to a 50 mL round-bottom flask to obtain the reaction solution. b. The reaction solution obtained in step a is heated to 70℃ and refluxed under continuous magnetic stirring for 4-6 hours. After cooling to room temperature, the target product is obtained by filtration. After further purification by recrystallization in methanol, it is dried in a vacuum oven at 50℃ for 12 hours to obtain the light green zero-dimensional discrete molecule N'4,N'5-bis((E)-4-(diphenylamino)benzylidene)-1H-imidazolium-4,5-dicarboxyhydrazide; and the bright yellow one-dimensional linear polymer N'4-ethylene-N'5-((E)-4-((4-((1E)-(2-(5-(2-ethylenehydrazine-1-carbonyl)-1H-imidazolium-4-carbonyl)hydrazine)methyl)phenyl)(phenyl)amino)benzylidene)-1H-imidazolium-4,5-dicarboxyhydrazide; Two-dimensional covalent organic framework materials: c. Dissolve tris(4-formylphenyl)amine and 1H-imidazolium-4,5-dicarboxyhydrazide at a mass ratio of 1.9:1 in a toluene / trimethylbenzene mixed solvent at a volume ratio of 2:1 using ultrasonication. Then add 0.04 volume equivalents of 3 mol / L acetic acid aqueous solution and 0.001 volume equivalents of aniline solution, mix well, and transfer to a 10 mL heat-resistant glass tube. d. After the heat-resistant glass tube was degassed by three consecutive cycles of freezing-vacuuming-thawing, it was sealed under high vacuum and placed in an oven at a constant temperature of 120℃ for 72 hours. After cooling to room temperature, it was filtered to obtain a pale yellow precipitate, which was then washed three times in sequence with tetrahydrofuran, acetone, dimethyl sulfoxide, and methanol. The product was then dried in a vacuum oven at 80℃ for 12 hours to obtain the target product, an acylhydrazone covalent organic framework.

3. The method for detecting synthetic cannabinoid FUB-INACA using a dimensionally controlled conformationally confined acylhydrazone sensing material as described in claim 1, characterized in that... Follow these steps: Detection of synthetic cannabinoids FUB-INACA using acylhydrazone sensing materials: a. The obtained zero-dimensional discrete molecules, one-dimensional linear polymers or two-dimensional covalent organic framework materials are ultrasonically dispersed in methanol to prepare an acylhydrazone-based sensing material detection reagent with a concentration of 0.045 mg / mL, and the detection reagent is packaged in a brown reagent bottle; Quantitative detection of synthetic cannabinoids using FUB-INACA solution: b. Dissolve the synthetic cannabinoid FUB-INACA in methanol solution to obtain a synthetic cannabinoid FUB-INACA standard solution with a concentration of 0 μmol / L-1000 μmol / L. c. Add the synthetic cannabinoid FUB-INACA standard solution with a concentration of 0 μmol / L to 1000 μmol / L obtained in step b to the acylhydrazone-based sensing material detection reagent obtained in step a. The volume ratio of the acylhydrazone-based sensing material detection reagent to the synthetic cannabinoid FUB-INACA standard solution is 4:

1. Under 395 nm excitation light, the fluorescence spectrum is measured. As the concentration of synthetic cannabinoid FUB-INACA increases, the zero-dimensional discrete molecule and the one-dimensional linear polymer show the characteristics of decreased fluorescence and increased fluorescence, respectively. The fluorescence emission peak of the two-dimensional covalent organic framework at 526 nm gradually increases, and the fluorescence color changes from colorless to green. The response time is less than 1 s. There is no response to other synthetic cannabinoids and traditional drugs. d. The fluorescence intensity at 526 nm was linearly fitted with the concentration of synthetic cannabinoid FUB-INACA to obtain a standard curve, which was used for the quantitative analysis of synthetic cannabinoid FUB-INACA in unknown samples.

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