CN107827825B

CN107827825B - Synthesis and application of benzimidazolyl supramolecular gelator based on hydroxynaphthalene formaldehyde functionalization

Info

Publication number: CN107827825B
Application number: CN201711076025.XA
Authority: CN
Inventors: 姚虹; 王姣; 樊彦青; 关晓文; 林奇; 魏太保; 张有明
Original assignee: Northwest Normal University
Current assignee: Northwest Normal University
Priority date: 2017-11-06
Filing date: 2017-11-06
Publication date: 2020-01-21
Anticipated expiration: 2037-11-06
Also published as: CN107827825A

Abstract

The benzimidazolyl supramolecular gelator based on the functionalization of hydroxynaphthalene formaldehyde is designed and synthesized, and in the molecules of the gelator, benzimidazole serves as a system with stable rigid structure, so that the main molecules emit strong fluorescence; the naphthalene ring is used as a signal reporting group, so that the host molecule has good aggregation state fluorescence performance, and the water solubility of the sensor molecule is enhanced. Organogel formed by the gelator in organic solvent is used for treating Fe³⁺、Al³⁺And CN^‑Has single selective fluorescence recognition performance. The organogel and iron ions are combined to form metal organogel, and the metal organogel can further remove binding force to identify L-cysteine, so that the fluorescence of a gel factor is recovered, and the OFF-ON signal of a sensor molecule is reflected. The synthesis of such "ON-OFF-ON" type sensor molecules enables multifunctional applications of the sensor.

Description

Synthesis and application of benzimidazolyl supramolecular gelator based on hydroxynaphthalene formaldehyde functionalization

Technical Field

The invention relates to a benzimidazolyl supramolecular gelator, in particular to a benzimidazolyl supramolecular gelator based on hydroxynaphthalene formaldehyde functionalization and a synthesis method thereof; the invention also relates to application of the supramolecular gel factor in colorimetric-fluorescent recognition of iron ions, L-cysteine, aluminum ions and cyanide, belonging to the field of ion detection.

Background

Iron is one of the trace elements necessary for human body. Iron is involved in the synthesis of myoglobin, cytochrome, hemoglobin, cytochrome oxidase and catalysts, while iron affects protein and hematopoietic vitamin metabolism and the synthesis of deoxyribonucleic acid. Because iron participates in hematopoietic function and the relationship between iron and enzyme, it is determined that iron deficiency can cause the reduction of leucocyte bactericidal ability, the increase of body infectivity and the damage of lymphocyte function, thereby causing the reduction of immunity. The lack of iron in the body generally causes the problems of lymphadenectasis, iron deficiency anemia, edema of limbs and the like. The detection of iron ions has important significance in the fields of environmental detection, life science and the like.

Amino acids are the basic units that make up proteins, and thus the importance of the efficacy and action of amino acids to the human body is self-evident. The total number of amino acids is 22, while the human body mainly needs 8 amino acids, and the efficacy and the effect of each amino acid are different, so that different amino acids are selected for supplementing for treating and preventing different diseases. L-cysteine is an amino acid having physiological functions, is the only amino acid having a reducing group of mercapto (-SH) among 20 kinds of amino acids constituting proteins, and has been widely used in medicines, food additives, and cosmetics today. Therefore, the detection of L-cysteine is of the same importance in the fields of life science, production and the like.

In industrial production, cyanide is widely applied to aspects of gold mining, electroplating, metallurgy and the like, and plays a very important role. However, cyanide is a highly toxic chemical in organisms and the environment, and is extremely toxic, especially to mammals. Cyanide can infiltrate into organism through respiratory tract, esophagus and skin to cause poisoning, and mild people have mucosa irritation symptom, lip and tongue numbness, asthma, nausea, emesis and palpitation. In severe cases, irregular breathing and gradually unconscious consciousness can lead to respiratory disorders and death. According to the data of the World Health Organization (WHO), the cyanide content in drinking water cannot exceed 19 mu mol/L at most, so that the selective detection of trace cyanide is necessary in a simple and intuitive manner.

Aluminum products are very common in everyday life, such as drinking water bottles, kitchen supplies, food additives and aluminum-based pharmaceuticals. In addition, more aluminum ions flow into the water resource due to acid rain. It is easy for people to take excessive aluminum ions from water and food. However, aluminum ions are neurotoxic to living bodies. It is well known that aluminum ions are associated with alzheimer's disease, parkinson's disease, smoking-related diseases and senile plaques.

In view of the wide application of chemical sensors in environmental science and life science, the design and synthesis of chemical sensors are attracting more and more attention in recent years. The design and synthesis of chemical sensors capable of rapidly and specifically recognizing specific ions has been a hot point of research, and many probes capable of singly recognizing iron ions and cysteine have been reported so far. However, there are few reports of continuous relay recognition of iron ions and cysteine using the same sensor molecule. In addition, the ion-responsive organogel is easy to prepare and convenient to use, and becomes a new research hotspot in the field of ion identification. Therefore, the development of the organogel capable of continuously identifying iron ions, L-cysteine, aluminum ions and cyanide has important application prospect.

Disclosure of Invention

The invention aims to provide a benzimidazolyl supramolecular gelator based on hydroxynaphthalene formaldehyde functionalization and a synthesis method thereof;

the invention also aims to provide an organic gel based on the supramolecular gelator and a preparation method thereof;

the invention also aims to provide a specific application of the organogel based on the gelator in colorimetric-fluorescent recognition of iron ions, L-cysteine, aluminum ions and cyanide.

Benzimidazolyl supermolecule gelator based on hydroxynaphthalene formaldehyde functionalization

The molecular formula of the supramolecular gelator is as follows: c₃₁H₃₈N₄O₂Named as: n' - ((2-hydroxynaphthalen-1-yl) methylene) -2- (2-undecyl-1H-benzimidazol-1-yl) acethydrazide labeled: s, the structural formula is as follows:

。

the preparation method of the supramolecular gelator S comprises the steps of taking absolute ethyl alcohol as a solvent, taking glacial acetic acid as a catalyst, reacting 2-undecyl-1H-benzimidazolyl-1-acethydrazide and 2-hydroxy-1-naphthaldehyde at a molar ratio of 1:2 ~ 1:10 at 80-80 ~ 90 ℃ for 8 ~ 10H, cooling to room temperature after the reaction is finished, performing suction filtration to remove the solvent, recrystallizing with DMF-EtOH to obtain a light yellow solid product, namely the sensor molecule S, wherein the dosage of the glacial acetic acid is 1 ~ 5 times of the total molar weight of a substrate, and the mass spectrogram of the sensor molecule S is shown in figure 1.

Rigid structural group benzimidazole and signal reporting group naphthalene ring are introduced into the molecule of the supramolecular gelator, so that the gelator has good aggregation state fluorescence performance, and the water solubility of the sensor molecule is enhanced.

Organic gel based on supermolecule gelator

The organic gel based on the supramolecular gelator S is formed by dissolving gelator S (N' - ((2-hydroxynaphthalene-1-yl) methylene) -2- (2-undecyl-1H-benzimidazole-1-yl) acethydrazide) in an organic solvent, and cooling to room temperature, and is marked as OG.

Wherein the organic solvent is ethylene glycol or glycerol, and the mass volume ratio of the gelator S to the organic solvent is 5 ~ 30 mg/ml.

The organic solvent is preferably glycerol due to the higher melting temperature of the organic solvent in the glycerol, and in the subsequent series of researches, the organic gel OG with the mass-to-volume ratio of 5 ~ 30mg/ml is selected to be formed in the glycerol.

Application of organic gel OG in ion detection

1. Fluorescence properties of organogels OG

FIG. 2 shows fluorescence emission spectra of organogel OG formed by gelator S in glycerol. As can be seen from fig. 2, the organogel OG has good fluorescence emission properties. Organogel OG fluoresces yellow (emission wavelength 525 nm) when the excitation wavelength is 420 nm.

2. Response of organogels OG to cations

2 times the molar amount of Mg (relative to the sensor molecule S) is added to the organogel OG²⁺、Ca²⁺、Cr³⁺、Fe³⁺、Co²⁺、Ni²⁺、Cu²⁺、 Zn²⁺、Ag⁺、Cd²⁺、Hg²⁺、Pb²⁺、Ba²⁺、Tb³⁺、Al³⁺、La³⁺And Eu³⁺In an aqueous solution (concentration: 0.1M), it was observed that only Fe was contained³⁺Can cause fluorescence quenching of the organogel OG (see FIG. 3), while the addition of other cations cannot produce similar fluorescence quenching performance, therefore, the organogel OG can realize the quenching to Fe³⁺A single selective response.

At the same time, only Al is found³⁺Can change the fluorescence color of the organic gel OG from yellow to blue, and the fluorescence of the organic gel OG is not changed by adding other cations (see figure 4), therefore, the organic gel OG can realize the effect on Al³⁺Single selective recognition of.

3. Response of organogels OG to anions

Adding F with the concentration of 0.1M into the organic gel OG respectively^-，Cl^-，Br^-，I^-，AcO^-，HSO₄ ^-，H₂PO₄ ^-，N₃ ^-，S^2-，SCN^-，ClO₄ ^-、CN^-In an aqueous solution of (2), only CN was found^-The fluorescence color of the organogel OG changes from yellow to blue (see FIG. 5), while that of the other anionsWith the addition, the fluorescence of the organogel OG does not change. Therefore, organogel OG can be implemented on CN^-Single selective recognition of.

Metal organic gel based on gelator S

Adding 0.5 ~ 5 times molar amount of Fe (III) salt into the organogel OG with the mass-volume ratio of 5 ~ 30mg/ml, and freely diffusing until the fluorescence of the organogel OG is completely quenched, namely forming the metal organogel FeG.

Application of metal organogel FeG in detection of L-cysteine

The metal organogel FeG was added in a 20-fold molar amount (relative to Fe)³⁺) L-Leu, L-Pro, L-Ary, L-Ser, L-Thr, L-Phe, L-Gln, L-IIe, L-Glu, L-Ala, L-Met, L-Val, L-Tyr, DL-Asp, L-His, L-Gly and L-Cys in an aqueous solution (concentration of 0.1M), and observing the response of the metal organogel FeG to various amino acids. As a result, it was found that the addition of only L-Cys recovered the fluorescence of the metal organogel FeG, and the color of the metal organogel was recovered from black to light yellow. While the addition of the remaining amino acids had no significant effect on the fluorescence of the metal organogel FeG. Thus, metal organogel FeG enables a single selective recognition of L-Cys. Meanwhile, the organic gel OG can continuously identify Fe through fluorescence³⁺And L-Cys. Adding 2 mol amount of Fe into organic gel OG³⁺L-Cys (relative to Fe) was added in an amount of 20 moles (relative to sensor molecule S) and to metal organogel FeG³⁺) Fluorescence spectrum of (see fig. 3: excitation wavelength 420nm, emission wavelength 536 nm).

To investigate the presence of organogel OG and metal organogel FeG, it was examined by Scanning Electron Microscopy (SEM) (organogel OG-0.5%). SEM was performed under the conditions of gold blasting of organogel OG and metal organogel FeG. As a result, as shown in FIG. 6, it was found that organogel OG exists in an overlapped concavo-convex nanopore structure when Fe is added thereto³⁺After the formation of the metal organogel FeG, the nanoporous structure is transformed into a lamellar structure. After adding L-Cys into the metal organogel FeG, the L-Cys competes for binding to Fe³⁺So that the sheet-like structure is transformed into a corrugated structure again.

In conclusion, the benzimidazolyl supramolecular gelator based on hydroxynaphthalene formaldehyde functionalization is designed and synthesized, and in molecules of the gelator, benzimidazole serves as a system with stable rigid structure, so that a main molecule emits strong fluorescence; the naphthalene ring is used as a signal reporting group, so that the host molecule has good aggregation state fluorescence performance, and the water solubility of the sensor molecule is enhanced. Organogel formed by the gelator in organic solvent is used for treating Fe³⁺、Al³⁺And CN^-Has single selective fluorescence recognition performance. The organogel and iron ions are combined to form metal organogel, and the metal organogel can further remove binding force to identify L-cysteine, so that the fluorescence of a gel factor is recovered, and the OFF-ON signal of a sensor molecule is reflected. The synthesis of such "ON-OFF-ON" type sensor molecules enables multifunctional applications of the sensor.

Drawings

FIG. 1 is a mass spectrum of gelator S prepared according to the present invention.

Fig. 2 shows fluorescence emission spectrum of organogel OG in glycerol.

FIG. 3 shows the addition of 2 times the molar amount of Fe to an organogel OG³⁺(a) And a fluorescence spectrum (excitation wavelength of 420nm, emission wavelength of 536 nm) obtained when 20 mol of L-Cys (b) was added to metal organogel FeG.

FIG. 4 shows the addition of 2 times the molar amount of Al to the organogel OG³⁺Fluorescence spectrum (excitation wavelength 420 nm).

FIG. 5 shows the addition of 20 times the molar amount of CN to the organogel OG^-Fluorescence emission spectrum (excitation wavelength 420 nm).

FIG. 6 is an SEM image of 0.5% (m/v) organogel OG, metal organogels FeG and FeG after addition of L-Cys.

Detailed Description

The synthesis of gelator S, organogels and their use in colorimetric/fluorescent recognition of iron ions and L-cysteine, aluminum ions and cyanide ions according to the invention are further illustrated by the following specific examples.

Example 1 preparation of gelator S

To 30ml of absolute ethanol, 1.36g (4X 10) of^-3mol) 2-undecyl-1H-benzimidazolyl-1-acethydrazide, 0.68g 2-hydroxy-1-naphthaldehyde (4X 10)^-3mol), 2ml of glacial acetic acid, reacting for 8h at the temperature of 80 ℃, cooling to room temperature after the reaction is finished, performing suction filtration to remove the solvent, and recrystallizing with DMF-EtOH to obtain a yellow solid product, namely the gelator S; the yield was 78.2%. The mass spectrum is shown in FIG. 1.

Example 2 preparation of organogel OG

0.005g of the gelator S prepared in example 1 was added to 1.00 ml of glycerin and heated to be sufficiently dissolved, and after standing and cooling to room temperature, organogel OG having a mass-to-volume ratio of 5mg/ml was formed.

Example 3 colorimetric/fluorescent identification of Organogel OG iron ions and L-cysteine

Transferring organogel OG into a series of drip plates, and adding Mg respectively²⁺、Ca²⁺、Cr³⁺、Fe³⁺、Co²⁺、Ni²⁺、Cu²⁺、Zn²⁺、Ag⁺、Cd²⁺、Hg²⁺、Pb²⁺、Ba²⁺、Tb³⁺、Al³⁺、La³⁺And Eu³⁺Cationic aqueous solution (concentration 0.1M) indicates that Fe is added dropwise when fluorescence of the organic gel OG is quenched and the color of the gel is changed from yellow to black³⁺If the fluorescence of the organogel is not quenched, it indicates that the dropwise addition is not Fe³⁺。

Remove and add Fe³⁺The organogel formed by (a) the metal organogel FeG was added to a series of spot plates, and aqueous solutions (concentration: 0.1M) of L-Leu, L-Pro, L-Ary, L-Ser, L-Thr, L-Phe, L-Gln, L-IIe, -Glu, L-Ala, L-Met, L-Val, L-Tyr, DL-Asp, L-His, L-Gly, and L-Cys were added, respectively, and when the fluorescence of the metal organogel FeG recovered, the color of the gel recovered from black to light yellow, it was indicated that L-Cys was added, and when the fluorescence of the metal organogel did not change, it was indicated that L-Cys was not added.

Example 4 OG colorimetric/fluorescent identification of aluminum ions

Transferring organogel OG into a series of drip plates, and adding Mg respectively²⁺、Ca²⁺、Cr³⁺、Fe³⁺、Co²⁺、Ni²⁺、Cu²⁺、Zn²⁺、Ag⁺、Cd²⁺、Hg²⁺、Pb²⁺、Ba²⁺、Tb³⁺、Al³⁺、La³⁺、Eu³⁺When the fluorescence color of the organogel changed from yellow to blue, the aqueous solution (concentration: 0.1M) of (A) indicates that Al was added dropwise³⁺If the fluorescence of the organogel is not changed, it indicates that Al is not added dropwise³⁺。

Example 5 OG colorimetric/fluorescent identification of CN^-

Transferring organic gel OG into a series of drip plates, and adding F^-、Cl^-、Br^-、 I^-、AcO^-、HSO₄ ^-、H₂PO₄ ^-、N₃ ^-、S^2-、SCN^-、ClO₄ ^-、CN^-If the fluorescence color of the organogel changes from yellow to blue, the aqueous solution (concentration: 0.1M) of (A) indicates that CN is added dropwise^-If the fluorescence of the organogel is not changed, it indicates that CN is not added dropwise^-。

Claims

1. The application of benzimidazolyl supermolecule organogel based on hydroxynaphthalene formaldehyde functionalization in cyanogen identification is characterized in that: transferring the organogel into a series of drop plates, and adding F^-，Cl^-，Br^-，I^-，AcO^-，HSO₄ ^-，H₂PO₄ ^-，N₃ ^-，S^2-，SCN^-，ClO₄ ^-、CN^-If the fluorescence color of the organogel changes from yellow to blue, the aqueous solution of (1) indicates that CN is added dropwise^-(ii) a If the fluorescence of the organogel is not changed, it indicates that the dropwise addition is not CN^-；

The organic gel is prepared by dissolving the supramolecular gelator into glycerol to form a solution with the mass-volume ratio of 5 ~ 30mg/ml, and cooling to room temperature to form stable condensed organic gel, wherein the structural formula of the supramolecular gelator is as follows:

。