阅读说明：本技术 一种荧光材料制备方法 (Preparation method of fluorescent material ) 是由 周英龙 于 2020-05-29 设计创作，主要内容包括：本发明提供一种荧光材料制备方法,具体涉及荧光材料领域；以苯二胺的摩尔量为基准,取2-4摩尔当量的4-取代基卤苯、0.02％摩尔量的钯催化剂、3-6摩尔当量的碱、1摩尔当量体积的甲苯,在110℃-130℃温度下反应12-24小时后,加二氯甲烷稀释,水洗,收集有机相,除去溶剂得粗产物；粗产物在甲醇中重结晶即得本产品；本发明仅合成荧光分子,简单高效、绿色环保。(The invention provides a preparation method of a fluorescent material, and particularly relates to the field of fluorescent materials; taking 2-4 molar equivalent of 4-substituent halogenobenzene, 0.02% molar of palladium catalyst, 3-6 molar equivalent of alkali and 1 molar equivalent of toluene as reference, reacting at 110-130 ℃ for 12-24 hours, adding dichloromethane for dilution, washing with water, collecting an organic phase, and removing the solvent to obtain a crude product; recrystallizing the crude product in methanol to obtain the product; the invention only synthesizes fluorescent molecules, is simple and efficient, and is green and environment-friendly.)

1. A method for preparing a fluorescent material is characterized in that the reaction equation is as follows:

the method comprises the following specific steps:

taking 2-4 molar equivalent of 4-substituted halogenobenzene, 0.02 mol% of palladium catalyst, 3-6 molar equivalent of alkali and 1 molar equivalent of benzene diamine as referenceThe volume of toluene is reacted for 12 to 24 hours at the temperature of 110 to 130 DEG CAdding dichloromethane for dilution, washing with water, collecting an organic phase, and removing the solvent to obtain a crude product; recrystallizing the crude product in methanol to obtain the product.

2. A method for preparing a fluorescent material according to claim 1, wherein:

the reaction mode is as follows:

adding 20 to 28mmol of 4-iodobenzonitrile, 8 to 12mmol of N, N' -diphenyl-1, 4-phenylenediamine and 25 to 35mmol of potassium tert-butoxide into a 100 to 140mL pressure-resistant reaction bottle in sequence, adding 8 to 12mL of anhydrous toluene, 0.17mmol of palladium acetate and 0.3 to 0.7mmol of tri-tert-butylphosphine tetrafluoroborate under the protection of argon gas, bubbling the reaction solution for 2 to 5 minutes by using argon gas, quickly screwing a bottle cover, magnetically stirring the reaction bottle on a heating plate at 100 to 140 ℃ for 22 to 26 hours, cooling, diluting the reaction solution by using 180 to 220mL of ethyl acetate, filtering, collecting filtrate, rotationally evaporating to remove the solvent, and carrying out silica gel column chromatography on the crude product by using 3:2 petroleum ether/dichloromethane as eluent to obtain an off-white solid, thus obtaining the product.

3. A method for preparing a fluorescent material according to claim 2, characterized in that: 24mmol of 4.37g of 4-iodobenzonitrile, 10mmol of 2.60g of N, N' -diphenyl-1, 4-phenylenediamine and 30mmol of 3.36g of potassium tert-butoxide are sequentially added into a 120mL pressure-resistant reaction bottle, 10mL of anhydrous toluene, 0.17mmol of 140mg of palladium acetate and 0.5mmol of 140mg of tri-tert-butylphosphine tetrafluoroborate are added under the protection of argon, the reaction solution is bubbled for 3 minutes by argon, a bottle cap is quickly screwed on, the reaction bottle is placed on a heating plate at 120 ℃ for magnetic stirring for 24 hours, after cooling, the reaction solution is diluted by 200mL of ethyl acetate, filtered, the filtrate is collected, the solvent is removed by rotary evaporation, and the crude product is separated by silica gel column chromatography by taking 3:2 petroleum ether/dichloromethane as eluent to obtain 4.38g of off-white solid with the yield of 95%.

Technical Field

The invention belongs to the field of fluorescent materials, and particularly relates to a preparation method of a fluorescent material.

Background

There are two main categories of fluorescent materials currently on the market. One is strong fluorescence in dilute solution, and the fluorescence becomes weak or disappears along with the increase of the concentration of the solution; the other is weak or no fluorescence in dilute solution, and strong fluorescence in solid state. The former belongs to aggregated fluorescence quenching (ACQ) and has the mechanism that intermolecular pi-pi action or other non-radiative channels influence the formation of excimers or exciplexes and consume excited state energy; most ACQ materials are condensed ring aromatic hydrocarbons with a planar structure, and the compounds are very stable, difficult to perform intramolecular movement even in a dilute solution and weak in fluorescence.

Disclosure of Invention

In view of the defects of the prior art, a preparation method of a fluorescent material is needed, which is simple, efficient, green and environment-friendly, can be used for synthesizing fluorescent molecules, and the prepared fluorescent material utilizes electron-rich functional groups as electron-donor chromophores to transfer electrons to electron-poor functional group acceptors in dilute solution, so as to emit strong fluorescence; in the solid or single crystal state, the molecular rotation is limited, so that the fluorescence is stronger than that in a dilute solution.

The invention provides the following technical scheme:

a novel fluorescent preparation method comprises the following specific steps: taking 2-4 molar equivalent of 4-substituent halogenobenzene, 0.02% molar of palladium catalyst, 3-6 molar equivalent of alkali and 1 molar equivalent of toluene as reference, reacting at 110-130 ℃ for 12-24 hours, adding dichloromethane for dilution, washing with water, collecting an organic phase, and removing the solvent to obtain a crude product; recrystallizing the crude product in methanol to obtain the product;

the reaction equation is as follows:

preferably, 20 to 28mmol of 4-iodobenzonitrile, 8 to 12mmol of N, N' -diphenyl-1, 4-phenylenediamine, 25 to 35mmol of potassium tert-butoxide, 8 to 12mL of anhydrous toluene, 0.17mmol of palladium acetate and 0.3 to 0.7mmol of tri-tert-butylphosphine tetrafluoroborate are sequentially added into a 100 to 140mL pressure-resistant reaction bottle under the protection of argon, the reaction solution is bubbled with argon for 2 to 5 minutes, the bottle cap is quickly screwed on, the reaction bottle is placed on a heating plate at 100 to 140 ℃ and is magnetically stirred for 22 to 26 hours, after cooling, the reaction solution is diluted with 180 to 220mL of ethyl acetate, filtered, the filtrate is collected, the solvent is removed by rotary evaporation, and the crude product is subjected to silica gel column chromatography by taking 3:2 petroleum ether/dichloromethane as eluent to obtain an off-white solid, namely the product;

the reaction mode is as follows:

preferably, 24mmol of 4.37g of 4-iodobenzonitrile, 10mmol of 2.60g of N, N' -diphenyl-1, 4-phenylenediamine and 30mmol of potassium tert-butoxide, 3.36g of potassium tert-butoxide are sequentially added into a 120mL pressure-resistant reaction flask, 10mL of anhydrous toluene, 0.17mmol of 140mg of palladium acetate and 0.5mmol of 140mg of tri-tert-butylphosphine tetrafluoroborate are added under the protection of argon, the reaction solution is bubbled for 3 minutes with argon, the flask cover is quickly screwed on, the reaction flask is placed on a heating plate at 120 ℃ and is magnetically stirred for 24 hours, after cooling, the reaction solution is diluted with 200mL of ethyl acetate, filtered, the filtrate is collected, the solvent is removed by rotary evaporation, and the crude product is chromatographically separated by a silica gel column by using 3:2 petroleum ether/dichloromethane as an eluent to obtain 4.38g of off-white solid with the yield of 95%.

The invention has the beneficial effects that:

the invention constructs a novel fluorescent material by introducing a D-A system and prolonging an intramolecular conjugated system in a single bond connection mode, and the material can emit strong fluorescence not only in a dilute solution, but also in a solid state, and even single crystals of the material also have strong fluorescence emission. It can meet the application requirements under various conditions. The production method of the material is simple, the target product is obtained by taking 4-substituted halogenobenzene and phenylenediamine as raw materials through Buchwald-Hartwig amination reaction with high yield, and the material is simple, efficient, green and environment-friendly; 4-substituent halogeno benzene and phenylenediamine are used as basic construction units to synthesize a novel fluorescent material with a D-A system. In a dilute solution, the fluorescent material transfers electrons to an electron-deficient functional group acceptor by using a chromophore group which takes an electron-rich functional group as an electron donor, so that strong fluorescence is emitted; in the solid or single crystal state, the molecular rotation is limited, so that the fluorescence is stronger than that in a dilute solution.

Detailed Description

A preparation method of a fluorescent material comprises the steps of sequentially adding 4-iodobenzonitrile (4.37g, 24mmol), N, N' -diphenyl-1, 4-phenylenediamine (2.60g, 10mmol), potassium tert-butoxide (3.36g, 30mmol) into a 120mL pressure-resistant reaction bottle, adding anhydrous toluene (10mL), palladium acetate (140mg, 0.17mmol) and tri-tert-butylphosphine tetrafluoroborate (140mg,0.5mmol) under the protection of argon, bubbling the reaction liquid for 3 minutes by using argon, quickly screwing a bottle cap, placing the reaction bottle on a heating plate at 120 ℃ for magnetic stirring for 24 hours, cooling, diluting the reaction liquid by using ethyl acetate (200mL), filtering, collecting filtrate, rotationally evaporating to remove a solvent, and carrying out silica gel column chromatography on a crude product by using petroleum ether/dichloromethane (3:2) as a eluent to obtain an off-white solid (4.38g, 95%).

H NMR(600MHz,CDCl₃)(ppm)＝7.78(d,J＝8.7Hz,4H),7.43(t,J＝7.7Hz,4H),7.15(d,J＝8.6Hz,4H),7.14(t,J＝7.4Hz,2H),7.06(d,J＝0.7Hz,4H),7.02(d,J＝8.8Hz,4H)；

The quantum efficiencies of three compounds, namely 4,4' - (1, 4-phenylenebis (phenylazadiyl)) dibenzyl nitrile, 3' - (1, 4-phenylenebis (phenylazadiyl)) dibenzyl nitrile and 2,2' - (1, 4-phenylenebis (phenylazadiyl)) dibenzyl nitrile, are 68% in a dichloromethane solution (the concentration is 5ppm), the solid quantum efficiency is 79% and the single crystal quantum efficiency is 72%; the 3-position substitution product is 42% in a dichloromethane solution (the concentration is 5ppm), the solid quantum efficiency is 51%, and the single crystal quantum efficiency is 47%; the 2-position substitution product was 16% in a dichloromethane solution (concentration of 5ppm), the solid quantum efficiency was 57%, and the single crystal quantum efficiency was 53%.

When the ACQ molecules are aggregated, they are easily stacked like layered graphite, and the un-excited low energy molecular layer and the excited high energy molecular layer are easily energy-transferred, and the energy is consumed without radiation transition, so that the luminescence is reduced or disappeared. The latter belongs to aggregation-induced emission (AIE) molecules, the mechanism is that the intramolecular rotation is limited, in solution, the free rotation of the substituents around a single bond consumes the excitation state energy, becomes a non-radiative decay channel, and causes weak fluorescence; in the aggregation state, due to space limitation, the molecular rotation is greatly hindered, the non-radiative decay channel is inhibited, and the excited state molecules can only decay back to the ground state through radiation, so that the fluorescence is obviously enhanced. The extension of the conjugated system is a very common method for exploring fluorescent materials, but most of the fluorescent materials obtained by the method are ACQ materials, and the ACQ materials have obvious defects of emitting weak fluorescence or no fluorescence in a solid state; in order to avoid large pi planes, freely selectable single bonds are added between the two, and most of fluorescent materials obtained by the method are AIE materials, namely weak fluorescence or no fluorescence is generated in a dilute solution. The donor-acceptor (donor-acceptor) system is a new type of fluorophore, a chromophore with electron-rich functional group as electron donor and an organic electroluminescent material with electron-deficient functional group as acceptor. The D-A fluorescent material has the following characteristics: can effectively adjust molecular energy level and change HOMO and LOMO orbital energy levels, and can generate electron transfer and energy transfer under the induction of light. A D-A system is taken as a chromophore, and a single bond is introduced to prolong a conjugated system, so that the fluorescent material can emit strong fluorescence in a dilute solution and in a solid state;

the invention synthesizes a novel fluorescent material with a D-A system by taking 4-substituent halogeno-benzene and phenylenediamine as basic construction units. In a dilute solution, the fluorescent material transfers electrons to an electron-deficient functional group acceptor by using a chromophore group which takes an electron-rich functional group as an electron donor, so that strong fluorescence is emitted; in the solid or single crystal state, the molecular rotation is limited, so that the fluorescent light emits stronger than that in dilute solution

Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the invention as defined by the appended claims. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.