A method for preparing an amide-based organic metal complex Zn-L

Abstract

A method for preparing organometallic complexes Zn-L based on amidated bisbenzimidazole groups, this invention relates to a method for preparing organometallic complexes Zn-L, using Zn 2+ Using a central ion and amidated bisbenzimidazole as a ligand, a zero-dimensional zinc metal complex (Zn-L) was synthesized via a solvothermal method. The prepared fluorescent probe exhibited excellent selectivity and sensitivity for fluoroquinolone antibiotics, and the hierarchical clustering analysis (HCA) platform enabled accurate identification of structurally similar fungible quantifiers (FQs). Compared to other fluorescent probes for detecting Ofloxacin, it had a similar or lower limit of detection (LOD). The detection limit of this fluorescent probe for Ofloxacin reached LOD = 0.0514 μM, indicating that the Zn-L complex is a fluorescent sensor with excellent application value for the rapid detection of fluoroquinolone drugs.

Description

Technical Field

[0001] This invention relates to a method for preparing organometallic complexes Zn-L, and particularly to a method for preparing organometallic complexes Zn-L based on amidated bisbenzimidazole groups. Background Technology

[0002] The widespread use of antibiotics has played a crucial role in treating bacterial infections, but it has also brought serious problems such as environmental pollution and bacterial resistance. Fluoroquinolone antibiotics, as a class of broad-spectrum antibacterial drugs, are widely used due to their high efficacy and broad spectrum in humans and animals, making them one of the most used antibiotics globally. Ofloxacin (OFL), a fluoroquinolone antibiotic, is widely used in livestock farming to treat bacterial infections and prevent diseases. However, if humans consume food containing OFL over a long period, this substance can accumulate in the body, thus harming health and posing risks of birth defects and cancer.

[0003] Traditional antibiotic detection methods typically require complex sample pretreatment, expensive equipment, and specialized personnel, limiting their widespread practical application. Due to these limitations, fluorescent probe technology, with its high sensitivity, rapid response, ease of operation, and low cost, has attracted considerable attention.

[0004] Zero-dimensional coordination complexes, including discrete organometallic clusters and mononuclear systems, exhibit significant advantages in sensing applications. In zero-dimensional systems, the fluorescence emission centers are not spatially confined, facilitating unimpeded analyte interactions and thus improving molecular recognition efficiency and accelerating response kinetics. Simultaneously, π-conjugated zero-dimensional complexes show particular promise through synergistic photophysical properties and unique interactions (such as π-π stacking, hydrogen bonding, and electrostatic effects), which collectively enhance sensing selectivity.

[0005] Therefore, exploring the preparation and application of a simple, easy-to-implement, highly selective, highly sensitive, simple-to-prepare, and low-cost zero-dimensional zinc-based complex has great application potential. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing organometallic complexes Zn-L based on amidated benzimidazole groups. This invention uses zinc chloride as the metal source and amidated benzimidazole groups as the organic ligands, and prepares Zn-L complexes via a solvothermal method. This method has the advantages of simple synthesis, convenient operation, and being environmentally friendly and pollution-free. The prepared fluorescent probe Zn-L exhibits excellent selectivity and sensitivity to fluoroquinolone antibiotics. Combined with hierarchical cluster analysis (HCA) discriminant platform, accurate identification of structurally similar fractional-quantitative (FQS) groups is achieved. This fluorescent probe, which selectively recognizes and detects fluoroquinolone antibiotics, possesses extremely high specificity, sensitivity, and excellent application prospects.

[0007] This invention is achieved through the following technical solution: A method for preparing organometallic complex Zn-L based on amidated benzimidazole group, wherein zinc chloride is used as a metal precursor, amidated benzimidazole group is used as an organic ligand, and Zn-L is prepared by solvothermal method; The preparation process includes the following: Synthesis of bis(1-benzimidazolyl)methane: Add benzimidazole to tetrahydrofuran and dissolve it completely. Then add NaH in small amounts several times. Add a mixed solution of dibromomethane and acetonitrile slowly dropwise into the reaction flask. The reaction temperature is 80℃ and the mixture is refluxed for 24 hours. Synthesis of 2-chloro-N-(2,6-diethylphenyl)acetamide: 2,6-Diethylaniline was added to dichloromethane and dissolved completely. 3-5 drops of triethylamine were then added. A mixed solution of chloroacetyl chloride and dichloromethane was slowly added dropwise to the reaction flask. The reaction was carried out at room temperature for 2 hours. Synthesis of amidated bisbenzimidazole ligand (L): bis(1-benzimidazole)methane and 2-chloro-N-(2,6-diethylphenyl)acetamide were mixed and acetonitrile was added to dissolve them completely; the reaction temperature was 100℃, and the mixture was refluxed for 48 h. Ligand L and precursor ZnCl2 were added to a hydrothermal reactor, and DMF and water were used as solvents. The mixture was stirred at room temperature until completely dissolved. The temperature was controlled by a program, and the reaction was carried out for 72 hours. The mixture was then cooled to room temperature to obtain Zn-L crystals.

[0008] The method for preparing an organometallic complex Zn-L based on amidated bisbenzimidazole is described above. The amidated bisbenzimidazole organometallic complex is used as a fluorescent probe Zn-L in the selective recognition of fluoroquinolone antibiotics by fluorescence detection.

[0009] The method for preparing the organometallic complex Zn-L based on amidated bisbenzimidazole group, and the application of the organometallic complex fluorescent probe Zn-L based on amidated bisbenzimidazole group in the selective recognition and detection of fluoroquinolone antibiotics, specifically involves dispersing the organometallic complex fluorescent probe Zn-L based on amidated bisbenzimidazole group in distilled water, ultrasonically treating it to obtain a probe solution, and then performing fluorescence detection.

[0010] The method for preparing organometallic complex Zn-L based on amidated bisbenzimidazole group, wherein the fluorescent probe exhibits selectivity and sensitivity to fluoroquinolone antibiotics, and the method combines hierarchical clustering analysis (HCA) discriminant platform to achieve accurate identification of structurally similar fungible quantifiers (FQs).

[0011] The method for preparing the organometallic complex Zn-L based on amidated bisbenzimidazole group is described above. The method preferably uses ofloxacin for quantitative fluorescence titration experiments. As the amount of antibiotic increases, the fluorescence intensity of the complex gradually decreases.

[0012] The method for preparing the organometallic complex Zn-L based on amidated bisbenzimidazole groups shows that, in a low concentration range, there is a linear relationship between I0 / I and the concentration of ofloxacin, and the approximate linear correlation analysis R... 2 =0.99781, corresponding to K of OFL sv The LOD is 1.23 × 10⁵ M. -1 And 0.0514μM.

[0013] The advantages and positive effects of this invention are: The fluorescent probe of this invention exhibits excellent selectivity and sensitivity to fluoroquinolone antibiotics, and the hierarchical clustering analysis (HCA) platform enables accurate identification of structurally similar fractional quantum structures (FQS). This invention utilizes ofloxacin, which exhibits good quenching effects, for quantitative fluorescent titration experiments. With increasing antibiotic dosage, the fluorescence intensity of the complex gradually decreases. In the low concentration range, a linear relationship exists between I0 / I and the concentration of ofloxacin, and the approximate linear correlation analysis shows R0. 2 =0.99781, corresponding to K of OFL sv The LOD and LOD are 1.23×10 5 M -1 And 0.0514 μM. It has a lower limit of detection compared to other LODs used to detect OFL fluorescent probes.

[0014] The significant features of this invention are: This invention utilizes zinc chloride as the metal source and amidated benzimidazole as the organic ligand to prepare Zn-L complexes via a solvothermal method. This method offers advantages such as simple synthetic pathways, convenient operation, and being environmentally friendly and pollution-free.

[0015] The fluorescent probe Zn-L prepared by this invention exhibits excellent selectivity and sensitivity to fluoroquinolone antibiotics, and the accurate identification of structurally similar FQS is achieved by combining it with the discriminant platform of hierarchical cluster analysis (HCA).

[0016] The fluorescent probe Zn-L prepared by this invention has excellent fluorescence quenching effect on ofloxacin, with a detection limit (LOD) of 0.0514 μM. Attached Figure Description

[0017] Figure 1 This is a diagram of the single-crystal structure of Zn-L; Figure 2 XRD pattern of Zn-L; Figure 3 The fluorescence intensity distribution of the fluorescent probe Zn-L under different FQS effects; Figure 4 An HCA tree diagram designed based on five experiments to distinguish and classify 12 FQS; Figure 5 The emission spectra of OFL at different concentrations; Figure 6 The graph shows the relationship between fluorescence intensity I0 / I and OFL concentration. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The mentioned embodiments are only some, not all, of the present invention. All other embodiments that can be obtained by those skilled in the art without creative effort based on the embodiments of the present invention are within the protection scope of the present invention.

[0019] One aspect of this invention provides a method for synthesizing organometallic complexes Zn-L based on amidated bisbenzimidazole groups, specifically comprising the following steps: (1) Synthesis of bis(1-benzimidazolyl)methane: Add benzimidazole to tetrahydrofuran and dissolve it completely. Then add NaH in small amounts several times. Add a mixed solution of dibromomethane and acetonitrile slowly dropwise into the reaction flask. The reaction temperature is 80℃ and the mixture is refluxed for 24h.

[0020] (2) Synthesis of 2-chloro-N-(2,6-diethylphenyl)acetamide: 2,6-Diethylaniline was added to dichloromethane and dissolved completely. Then, 3-5 drops of triethylamine were added. A mixed solution of chloroacetyl chloride and dichloromethane was slowly added dropwise to the reaction flask. The reaction was carried out at room temperature for 2 hours.

[0021] (3) Synthesis of amidated bisbenzimidazole ligand (L): Bis(1-benzimidazole)methane and 2-chloro-N-(2,6-diethylphenyl)acetamide were mixed and acetonitrile was added to dissolve them completely. The reaction temperature was 100℃ and the mixture was refluxed for 48 h.

[0022] (4) Add ligand L and precursor ZnCl2 to a hydrothermal reactor, using DMF and water as solvents, and stir at room temperature until completely dissolved. After 72 hours of temperature control, cool to room temperature to obtain Zn-L crystals.

[0023] The second invention relates to the application of an organometallic complex fluorescent probe Zn-L based on amidated bisbenzimidazole groups in the selective recognition and detection of fluoroquinolone antibiotics using fluorescence detection. The specific method is as follows: The organometallic fluorescent probe Zn-L based on amidated bisbenzimidazole group was dispersed in distilled water, sonicated to obtain the probe solution, and then subjected to fluorescence detection. Example 1

[0024] 1. Preparation of Zn-L (1) Synthesis of bis(1-benzimidazolyl)methane: Add benzimidazole to tetrahydrofuran and dissolve it completely. Then add NaH in small amounts several times. Add a mixed solution of dibromomethane and acetonitrile slowly dropwise into the reaction flask. The reaction temperature is 80℃ and the mixture is refluxed for 24h.

[0025] (2) Synthesis of 2-chloro-N-(2,6-diethylphenyl)acetamide: 2,6-Diethylaniline was added to dichloromethane and dissolved completely. Then, 3-5 drops of triethylamine were added. A mixed solution of chloroacetyl chloride and dichloromethane was slowly added dropwise to the reaction flask. The reaction was carried out at room temperature for 2 hours.

[0026] (3) Synthesis of amidated bisbenzimidazole ligand (L): Bis(1-benzimidazole)methane and 2-chloro-N-(2,6-diethylphenyl)acetamide were mixed and acetonitrile was added to dissolve them completely. The reaction temperature was 100℃ and the mixture was refluxed for 48 h.

[0027] (4) Add ligand L and precursor ZnCl2 to a hydrothermal reactor, using DMF and water as solvents, and stir at room temperature until completely dissolved. After 72 hours of temperature control, cool to room temperature to obtain Zn-L crystals.

[0028] 2. Structural characterization of Zn-L The structure of Zn-L was characterized using X-ray single-crystal diffraction. Figure 1 The image shows the single-crystal structure of this complex. X-ray powder diffraction (PXRD) analysis of the sample powder was performed using a powder diffractometer. Figure 2 As shown, it can be observed that its PXRD spectrum is very consistent with the simulated spectrum generated by X-ray diffraction data, indicating that the synthesized Zn-L has good phase purity. Example 2

[0029] Probe preparation The synthesized Zn-L solid was directly dispersed in 10 mL of distilled water and subjected to ultrasonic treatment to obtain a probe solution, which was then subjected to fluorescence detection. Example 3

[0030] Fluorescent response of the probe to fluoroquinolone antibiotics To evaluate the response of Zn-L to fluoroquinolone antibiotics, different fluoroquinolone antibiotics (ofloxacin (OFL), dafluxacin (DAN), norfloxacin (NOR), safloxacin (SAR), mabofloxacin (MBF), ciprofloxacin (CIP), difloxacin (DIF), fleroxacin (FLE), moxifloxacin hydrochloride (MOX), enoxacin (ENO), pefloxacin (PEF), lomefloxacin hydrochloride (LOM); 0.6 mM) were added to the probe solution. Figure 3 As shown, the developed fluorescent probe exhibits excellent selectivity and sensitivity to fluoroquinolone antibiotics. Figure 4 As shown, the discriminant platform combined with hierarchical clustering analysis (HCA) achieves accurate identification of structurally similar FQS. Example 4

[0031] Fluorescence detection of ofloxacin by probe Ofloxacin, which has the best quenching effect, was selected for quantitative detection, such as... Figure 5 As shown, the fluorescence intensity of the probe Zn-L gradually decreases with increasing ofloxacin concentration. Figure 6 This indicates a linear relationship between I0 / I and ofloxacin concentration, and the approximate linear correlation analysis shows R0. 2 =0.99781, corresponding to K of OFL sv The LOD and LOD are 1.23×10 5 M -1 and 0.0514 μM (LOD=3σ / K) sv , where σ represents the standard deviation of the fluorescence intensity of 10 replicates in the blank sample.

Claims

1. A method for preparing organometallic complexes Zn-L based on amidated bisbenzimidazole groups, characterized in that, The method uses zinc chloride as a metal precursor and amidated benzimidazole group as an organic ligand to prepare Zn-L by a solvothermal method; The preparation process includes the following: Synthesis of bis(1-benzimidazolyl)methane: Add benzimidazole to tetrahydrofuran and dissolve it completely. Then add NaH in small amounts several times. Add a mixed solution of dibromomethane and acetonitrile slowly dropwise into the reaction flask. The reaction temperature is 80℃ and the mixture is refluxed for 24 hours. Synthesis of 2-chloro-N-(2,6-diethylphenyl)acetamide: 2,6-Diethylaniline was added to dichloromethane and dissolved completely. 3-5 drops of triethylamine were then added. A mixed solution of chloroacetyl chloride and dichloromethane was slowly added dropwise to the reaction flask. The reaction was carried out at room temperature for 2 hours. Synthesis of amidated bisbenzimidazole ligand (L): bis(1-benzimidazole)methane and 2-chloro-N-(2,6-diethylphenyl)acetamide were mixed and acetonitrile was added to dissolve them completely; the reaction temperature was 100℃, and the mixture was refluxed for 48 h. Ligand L and precursor ZnCl2 were added to a hydrothermal reactor, and DMF and water were used as solvents. The mixture was stirred at room temperature until completely dissolved. The temperature was controlled by a program, and the reaction was carried out for 72 hours. The mixture was then cooled to room temperature to obtain Zn-L crystals.

2. The method for preparing the organometallic complex Zn-L based on amidated bisbenzimidazole group according to claim 1, characterized in that, The aminated bisbenzimidazole organometallic complex is used in the selective recognition of fluoroquinolone antibiotics by the fluorescent probe Zn-L.

3. A method for preparing an organometallic complex Zn-L based on an amidated bisbenzimidazole group according to claim 1 or 2, characterized in that, The application of the organometallic complex fluorescent probe Zn-L based on amidated bisbenzimidazole group in the selective recognition and detection of fluoroquinolone antibiotics is as follows: the organometallic complex fluorescent probe Zn-L based on amidated bisbenzimidazole group is dispersed in distilled water, ultrasonically treated to obtain a probe solution, and then subjected to fluorescence detection.

4. A method for preparing an organometallic complex Zn-L based on an amidated bisbenzimidazole group according to claim 1 or 2, characterized in that, The fluorescent probe exhibits selectivity and sensitivity to fluoroquinolone antibiotics, and the hierarchical clustering analysis (HCA) discriminant platform enables accurate identification of structurally similar fungibles (FQs).

5. A method for preparing an organometallic complex Zn-L based on an amidated bisbenzimidazole group according to claim 1 or 2, characterized in that, The method preferably uses ofloxacin for quantitative fluorescence titration experiments; as the dosage of antibiotics increases, the fluorescence intensity of the complex gradually decreases.

6. A method for preparing an organometallic complex Zn-L based on an amidated bisbenzimidazole group according to claim 1 or 2, characterized in that, The method shows a linear relationship between I0 / I and ofloxacin concentration in the low concentration range, with an approximate linear correlation analysis R0. 2 =0.99781, corresponding to K of OFL sv The LOD is 1.23 × 10⁵ M. -1 And 0.0514μM.

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