CN108822084B - Tetraphenyl ethylene bridged tetraphenylimidazole salt and preparation method and application thereof - Google Patents

Abstract

The invention discloses a preparation method and application of a tetraphenylimidazole salt compound based on a tetraphenylethylene bridge. The method comprises the steps of taking 4,4 ' -dihydroxy benzophenone as a raw material in an organic solvent, carrying out Mc Murry reaction to obtain 1,1 ', 2,2 ' -tetrahydroxy tetraphenylethylene, further reacting the 1, 2-dibromoethane to obtain 1,1 ', 2,2 ' -tetra [4- (2-bromoethoxy) phenyl ] ethylene, reacting the 1,1 ', 2,2 ' -tetra [4- (2-bromoethoxy) phenyl ] ethylene with N-pyridylmethylenebenzimidazole to obtain tetraphenylethylene bridged tetraphenylimidazole salt bromide, and carrying out anion exchange reaction on the tetraphenylethylene bridged tetraphenylimidazole salt bromide and hexafluorophosphate to obtain tetraphenylethylene bridged tetraphenylimidazole hexafluorophosphate (1). The tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound has the advantages of simple preparation and obvious fluorescent photosensitive effect, can be used for preparing a fluorescent molecular recognition system, and is mainly applied to the technical field of fluorescent recognition.

Description

Tetraphenyl ethylene bridged tetraphenylimidazole salt and preparation method and application thereof

Statement regarding sponsoring research or development

The invention is carried out under the subsidy of national science fund (fund number: 21572159).

Technical Field

The invention belongs to the technical field of organic chemistry, and relates to a tetraphenylimidazole hexafluorophosphate compound taking benzimidazole, 4' -dihydroxy benzophenone, zinc powder and 1, 2-dibromoethane as raw materials, in particular to a preparation method of the tetraphenylimidazole hexafluorophosphate compound and a research on fluorescence recognition performance of the tetraphenylimidazole hexafluorophosphate compound.

Background

Benzimidazole derivatives, have a wide range of applications ranging from simple carbene transfer to related biological applications. Benzimidazole compounds have a specific structure, physiological activity, reactivity, and the like, and they are highly favored by researchers in the fields of chemistry and pharmacy. The benzimidazole salt compounds and derivatives thereof are also widely applied to the fields of organic materials and the like. The tetraphenyl vinyl has larger size, has a propeller-shaped structure with a peripheral benzene ring capable of freely rotating, shows a plurality of unique performances, and has wide application prospects in the fields of photoelectric materials, biological imaging and the like. The derivative has excellent luminous performance, the functional group is easy to modify, and the original inherent characteristics can be changed by introducing different bridge chains, so that the derivative exerts more advantages. In addition, the compounds are convenient to synthesize, easy to functionalize and obvious in luminous effect, so that the compounds attract more and more people in recent years. With the research depth and the research range expansion, the tetraphenylimidazole salt bridged by tetraphenyl ethylene can be widely applied in the fields of chemical disciplines, life disciplines, environmental analysis and the like.

Disclosure of Invention

The invention aims to provide a tetraphenylethylene bridged tetraphenylimidazole hexafluorophosphate compound and a preparation method thereof.

The invention further relates to application of the tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound in the field of fluorescence recognition.

In order to accomplish the above objects, the technical solution of the present invention is as follows:

a compound which is a tetraphenylethylene-bridged tetraphenylimidazolium salt having the structure:

the preparation method of the tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound is characterized by comprising the following steps of:

(1) after mixing zinc powder and an organic solvent, dropwise adding titanium tetrachloride into the mixed solution, heating and stirring for 1 hour, and then dropwise adding 4,4 ' -dihydroxy benzophenone to obtain 1,1 ', 2,2 ' -tetrahydroxy tetraphenylethylene;

(2) 1,1 ', 2, 2' -tetrahydroxy tetraphenylethylene is used as a raw material to react with 1, 2-dibromoethane in an organic solvent to obtain 1,1 ', 2, 2' -tetrakis [4- (2 '' -bromoethoxy) phenyl ] ethylene, wherein the molar ratio of the 1,1 ', 2, 2' -tetrahydroxy tetraphenylethylene to the 1, 2-dibromoethane is 1: 16;

(3) reacting the obtained 1,1 ', 2, 2' -tetrakis [4- (2 '' -bromoethoxy) phenyl ] ethylene with N-pyridylmethylenebenzimidazole in an organic solvent to obtain a bromide of a tetraphenylethylene-bridged tetraphenylimidazolium salt;

(4) bromination of tetraphenylimidazolium salts bridged with tetraphenylethyleneSubstance and NH₄PF₆In a molar ratio of 1: 8, dissolving the mixture in an organic solvent, reacting at room temperature for 3 days, filtering and washing to obtain the tetraphenylethylene bridged tetraphenylimidazolium hexafluorophosphate (1).

The preparation method comprises the following steps of preparing raw materials of zinc powder, 4' -dihydroxy benzophenone, dilute hydrochloric acid, potassium carbonate, titanium tetrachloride, 1, 2-dibromoethane, ammonium hexafluorophosphate, benzimidazole and chloromethyl pyridine hydrochloride;

the organic solvent is one or a mixture of more of tetrahydrofuran, acetone, methanol, diethyl ether, acetonitrile and ethyl acetate.

A typical tetraphenylethylene-bridged tetraphenylimidazolium hexafluorophosphate compound:

typical tetraphenylethylene-bridged tetraphenylimidazolium hexafluorophosphates have the formula C₈₆H₇₆F₂₄N₁₂O₄P₄。

The invention further discloses the application of the tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound in the field of fluorescence recognition; the fluorescent recognition refers to the recognition of Li⁺，Na⁺，K⁺，NH₄ ⁺，Ag⁺，Ca²⁺，Co²⁺，Ni²⁺，Cu²⁺，Zn²⁺，Cd^{2 +}，Al³⁺，Pb²⁺And Cr³⁺The result shows that: main body 1 to Ag⁺Having selective recognition capability;

at 25 ℃ with tetraphenyl ethylene bridged tetraphenylimidazolium hexafluorophosphate compounds as hosts and different nitrate species as guests (different nitrates, e.g. Li⁺，Na⁺，K⁺，NH₄ ⁺，Ag⁺，Ca²⁺，Co²⁺，Ni²⁺，Cu²⁺，Zn²⁺，Cd²⁺，Al³⁺，Pb²⁺And Cr³⁺) Dissolving a host and an object in an organic solvent, mixing the host solution with different object solutions respectively under a certain concentration, measuring the fluorescence spectrum of the mixture, and finding out the object which can be identified by the host. For the guest that the host can recognize, the host was titrated with different concentrations of guest (1.0 × 10)^-6 mol/L^-1) The fluorescence spectrum was measured. Adding nitrate solution (0-33.0 × 10) with gradually increasing concentration by microsyringe^-6 mol/L^-1). The excitation wavelength of the main solution is 345 nm, and the emission spectrum has an emission peak at 465 nm. After each addition, reaction equilibrium was reached for 8-10 minutes to determine the corresponding fluorescence intensity. The tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound used as the main body has an obvious fluorescent sensitization effect on nitrate compounds, has obvious fluorescent emission at 465 nm in a fluorescent spectrum, can be used for manufacturing a fluorescent probe, and is expected to be applied in the field of fluorescence chemistry.

The invention mainly solves the problem of cation recognition of tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate, mainly inspects the recognition of silver ions, has the main difficulties of synthesis of a main compound and selection of bonding points in the main compound, and successively inspects alkyl, hydroxyethyl, aminoethyl and other side chains with different lengths, and finally determines the scheme that a picolyl side chain is selected as the bonding point.

The tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound provided by the invention is a high-grade fluorescent material which can stably exist in a standard state, has the advantages of simple preparation and obvious fluorescent photosensitive effect, can be used for preparing fluorescent materials and fluorescent molecule recognition systems, and is expected to be applied in the field of fluorescence chemistry.

Drawings

FIG. 1 shows tetraphenylimidazole hexafluorophosphate compounds containing tetraphenylethylene bridge (application example 1) with Li added to ethanol/dimethylsulfoxide solution (v: v = 99:1) at 25 ℃ C⁺，Na⁺，K⁺，NH₄ ⁺，Ag⁺，Ca²⁺，Co²⁺，Ni²⁺，Cu²⁺，Zn²⁺，Cd²⁺，Al³⁺，Pb²⁺And Cr³⁺Fluorescence spectrum after nitrate; the results show that the host is 1 to Ag⁺Having selective recognition capability;

FIG. 2 is a tetraphenyl ethylene bridged tetraphenyl imidazole hexafluorophosphate compound (application example 1) with Li addition to ethanol/dimethylsulfoxide solution (v: v = 99:1) at 25 ℃ C⁺，Na⁺，K⁺，NH₄ ⁺，Ag⁺，Ca²⁺，Co²⁺，Ni²⁺，Cu²⁺，Zn²⁺，Cd^{2 +}，Al³⁺，Pb²⁺And Cr³⁺Fluorescence titration spectrogram after nitrate; the results show that with Ag⁺The fluorescence of the host gradually increases as the concentration increases, when Ag⁺After the concentration reaches a certain value, the fluorescence is not obviously enhanced.

FIG. 3 shows the addition of Li to a tetraphenyl ethylene bridged tetraphenylimidazole hexafluorophosphate compound (application example 1) in an ethanol/dimethylsulfoxide solution (v: v = 99:1) at 25 ℃ C⁺, Na⁺, K⁺, NH₄ ⁺, Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cu^{2 +}, Zn²⁺, Cd²⁺, Al³⁺, Pb²⁺And Cr³⁺Ultraviolet titration absorption spectrogram after nitrate; the results show that with Ag⁺The absorption peak of the main body is gradually enhanced when the concentration is increased, when Ag⁺The absorption peak is not obviously enhanced after the concentration reaches a certain value; and the binding ratio of the host to the guest is 1: 2.

Detailed Description

The invention is described below by means of specific embodiments. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. In addition, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications in the components and amounts of the materials used in these embodiments can be made without departing from the spirit and scope of the invention.

The raw materials and reagents used in the invention are commercially available; specifically, zinc powder, benzimidazole, 1, 2-dibromoethane, 4' -dihydroxybenzophenone, chloromethylpyridine hydrochloride, and the like, which are starting materials for preparing the compound of the present invention, are commercially available or can be easily prepared by known methods. The reagents used for preparing the compound are all from Keruisi chemical Co., Ltd, Tianjin, and the grade is analytical purity.

It should be further noted that: all experimental procedures were performed using Schlenk techniques and the solvents were purified by standard procedures. All reagents used for synthesis and analysis were analytically pure and were not further processed. Melting points were determined by a Boetius zone cutter.¹H and¹³C{¹h } NRM spectra were recorded by mercury variable Vx400 spectrophotometer, measurement interval: 400 MHz and 100 MHz. Chemical shift, as determined by international standard TMS. Fluorescence spectra were determined by Cary Eclipse fluorescence spectrophotometer.

Example 1

Preparation of 1,1 ', 2, 2' -tetrahydroxytetraphenylethylene

1.700 g (26.5 mmol) of zinc powder was charged into a three-necked round-bottomed flask with 50 mL of THF for removing water, and stirred. Cooling the mixture to 0 ℃ by using an ice bath, slowly dropwise adding 1.4 mL (13.0 mmol) of titanium tetrachloride by using a pipette under the protection of nitrogen, removing the ice bath after dropwise adding, stirring for 10 min at room temperature, heating and refluxing for 2.5 h, stopping heating, cooling to room temperature, dissolving 3.000 g (6.6 mmol) of 4, 4' -dihydroxy benzophenone in water-removing THF (tetrahydrofuran) for dropwise adding, continuously heating and refluxing for 1 day after dropwise adding is finished, cooling to room temperature, slowly adding a dilute hydrochloric acid aqueous solution, stirring, carrying out suction filtration, extracting 3 × 50 mL of ethyl acetate, drying, carrying out suction filtration, and carrying out rotary evaporation on filtrate to remove the ethyl acetate. The crude product was obtained as a pink solid and purified with acetone to give a solid 3.142 g, yield: and 55 percent. Melting point:> 300 ˚C。¹H NMR (400 MHz, DMSO-d ₆): 6.45 (d, J = 4.2 Hz, 8H, PhH), 7.05 (d, J = 4.3 Hz, 8H, PhH), 8.93 (s, 4H, OH).

preparation of 1,1 ', 2, 2' -tetrakis [4- (2 '' -bromoethoxy) phenyl ] ethylene

2.000 g (5.0 mmol) of 1,1 ', 2, 2' -tetrahydroxytetraphenylethylene are reacted with CH₃CN was dissolved, and 7.561 g (75.8 mmol) of anhydrous K were added₂CO₃Then, the mixture was stirred under reflux for 1.5 hours. The above solution was poured into a constant pressure dropping funnel, and then added dropwise to a three-necked flask containing 15.263 g (101.0 mmol) of 1, 2-dibromoethane, and the reflux was kept at 2 days. After the reaction is finished, the system is cooled to room temperature, the mixture is filtered, acetonitrile is removed through rotary evaporation to obtain a yellow oily substance, methanol is dripped to separate out a light yellow solid, the light yellow solid is purified by the methanol, and then 1, 4-dioxane and n-hexane are used for recrystallization, and the white solid 2.173 g is obtained through suction filtration. Yield: 52 percent. Melting point: 121 + 122 ℃.¹H NMR (400 MHz, DMSO-d ₆): 3.77 (t, J = 5.2 Hz, 8H, CH ₂), 4.24 (t, J = 4.8 Hz, 8H, CH ₂), 6.72 (d, J = 8.8 Hz, 8H, PhH), 6.83 (d, J = 9.1 Hz, 8H, PhH).

N-Preparation of pyridine methylene benzimidazole

3.280 g (58.4 mmol) of KOH, 0.320 g (1.0 mmol) of TBAB are added to 100 mL of THF which is freed of water, stirred at room temperature and then 1.728 g (14.4 mmol) of benzimidazole in 50 mL of THF are added dropwise. Heating to 60 ℃ for reaction for 1 hour after dripping, adding 2.400 g (14.4 mmol) of 2-chloromethylpyridine hydrochloride, and carrying out reflux reaction for 48 hours. Filtering and rotary steaming. The crude product was washed with 100 mL of water, CH₂Cl₂Extracting, separating liquid, drying, suction filtering, rotary evaporating to remove CH₂Cl₂Recrystallization from diethyl ether gave 2.800 g of a pale yellow solid. Yield: 91.4%, melting point 106-.

1,1 ', 2,2 ' -tetrakis {4- [2 ' ' - (2) 'NBenzimidazolylmethylenepyridine) ethoxy]Preparation of phenyl } ethylene hexafluorophosphate salt (1)

1.500 g (1.8 mmol) of 1,1 ', 2, 2' -tetrakis [4- (2-bromoethoxy) phenyl]Ethylene and3.058 g (14.5 mmol) Ndissolving pyridine methylene benzimidazole in 60 mL of acetonitrile for reaction, heating and refluxing for 6 days, and after the reaction is finished, removing acetonitrile by rotary evaporation to obtain a crude product, and purifying the crude product by using acetone to obtain tetraphenylimidazole bromide. Then with NH₄PF₆Anion exchange was carried out in methanol solution to give the corresponding white tetrabenzimidazole hexafluorophosphate (1). Yield: 1.925 g. Yield: and 55 percent. Melting point: 220 + 222 ℃.¹H NMR (400 MHz, DMSO-d ₆): 4.33 (s, 8H, CH ₂), 4.95 (s, 8H, CH ₂), 5.92 (s, 8H, CH ₂), 6.63 (d, J = 8.6 Hz, 8H, PhH), 6.74 (d, J = 8.60 Hz, 8H, PhH), 7.32 (m,4H, PyH), 7.62 (m, 8H, PhH), 7.64 (m, 4H, PyH), 7.85 (t, 4H, PyH), 7.93 (d, J = 8.40 Hz, 4H, PhH), 8.11 (d, J = 8.80 Hz, 4H, PhH), 8.36 (d, J = 4.40 Hz, 4H, PyH), 9.96 (s, 4H, bimiH). ¹³C NMR (100 MHz, DMSO-d ₆): 155.9 (PhC), 152.9 (PyC), 149.4 (PyC), 143.6 (bimiC), 137.4 (PyC), 136.7 (C=C), 131.8 (PyC), 131.2 (PyC), 131.1 (PhC), 126.9 (PhC),126.7 (PhC), 125.51 (PhC), 123.6 (PhC), 122.6 (PhC), 114.1 (PhC), 114.0 (PhC), 113.7 (PhC), 65.0 (OCH₂CH₂), 50.7 (NCH₂Py), 46.4 (NCH₂).

The experimental procedure was as follows:

application example 1

In a solution of tetraphenylethylene-bridged tetraphenylimidazolium hexafluorophosphate compounds in ethanol/dimethylsulfoxide (v: v = 99:1) at 25 ℃ (1 × 10)^-6mol/L) of the same concentration of different species (30X 10)^-6mol/L) solution of nitrates (Li)⁺，Na⁺，K⁺，NH₄ ⁺，Ag⁺，Ca²⁺，Co²⁺，Ni²⁺，Cu²⁺，Zn²⁺，Cd²⁺，Al³⁺，Pb²⁺And Cr³⁺) The fluorescence spectrum was measured and shown in FIG. 1.

The fluorescence titration was measured by a Cary Eclipse fluorescence spectrophotometer using a 1 cm path length quartz cell. The titration was carried out by subjecting the bulk (1X 10)^-6 mol/L^-1) Put into a 4 mL cuvette and added with increasing concentrations of Ag using a microsyringe⁺Solution (0-33.0X 10)^-6 mol/L^-1). The excitation wavelength of the main solution is 345 nm, and the emission spectrum has an emission peak at 465 nm. After each addition, the reaction equilibrium was reached for 8-10 minutes to determine the fluorescence intensity. Data analysis used Origin 8.0, see figure 2.

UV titration was determined by JASCO-V570 spectrophotometer using a 1 cm path length quartz cuvette. Titration was performed by placing the receptor in a 4 mL cuvette and maintaining the concentration of the host at 1.0X 10^-6At mol/L, Ag⁺The concentration of the ions varies from 0 to 70.0X 10^-6mol/L. The absorption spectrum in the range of 235-360 nm was recorded. The UV spectrum was measured at reaction equilibrium for 8-10 minutes after each addition. Data analysis used Origin 8.0. See figure 3.

In summary, the content of the present invention is not limited to the examples, and those skilled in the art can easily suggest other examples within the technical teaching of the present invention, but such examples are included in the scope of the present invention.

Claims (3)

1. A tetraphenylethylene-bridged tetraphenylimidazolium compound having the structure:

1。

2. the process for producing a tetraphenylethylene-bridged tetraphenylimidazolium compound according to claim 1, characterized by the following steps:

(1) after mixing zinc powder and an organic solvent, dropwise adding titanium tetrachloride into the mixed solution, heating and stirring for 1 hour, and then dropwise adding 4,4 ' -dihydroxy benzophenone to obtain 1,1 ', 2,2 ' -tetrahydroxy tetraphenylethylene; wherein the zinc powder: titanium tetrachloride: the molar ratio of 4, 4' -dihydroxy benzophenone is 4: 2: 1;

(2) 1,1 ', 2, 2' -tetrahydroxy tetraphenylethylene is used as a raw material to react with 1, 2-dibromoethane in an organic solvent to obtain 1,1 ', 2, 2' -tetrakis [4- (2-bromoethoxy) phenyl ] ethylene, wherein the molar ratio of the 1,1 ', 2, 2' -tetrahydroxy tetraphenylethylene to the 1, 2-dibromoethane is 1: 16;

(3) reacting the obtained 1,1 ', 2, 2' -tetrakis [4- (2-bromoethoxy) phenyl ] ethylene with N-pyridylmethylenebenzimidazole in an organic solvent to obtain a tetraphenylethylene-bridged tetraphenylimidazolium bromide; wherein the molar ratio of the 1,1 ', 2, 2' -tetra [4- (2-bromoethoxy) phenyl ] ethylene to the N-pyridine methylene benzimidazole is 1: 7;

(4) bromide of tetraphenylimidazolium salt bridged with tetraphenylethylene and NH₄PF₆In a molar ratio of 1: 8, dissolving the mixture in an organic solvent, reacting at room temperature for 3 days, filtering and washing to obtain the tetraphenylethylene bridged tetraphenylimidazolium hexafluorophosphate (1).

3. The use of the tetraphenylethylene-bridged tetraphenylimidazolium compound according to claim 1 in the field of fluorescence recognition; the fluorescence recognition refers to the recognition of Ag⁺Identification of (1).

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