CN114634546A - High-luminous-power photochromic material from red to near infrared and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of high luminous power photochromic materials, and provides a high luminous power photochromic material from red to near infrared and a preparation method thereof, wherein the preparation method comprises the following steps of 1, weighing 7-bromo-4-aldehyde benzo [ c ] [1,2,5] thiadiazole, triphenylamine boric acid, tetratriphenyl phosphorus palladium and sodium carbonate, preparing the sodium carbonate into a sodium carbonate aqueous solution, and dissolving the raw materials in chromatographic toluene and tetrahydrofuran; then extracting, filtering, separating by column chromatography and rotary evaporating to obtain red powder to obtain 7-triphenylamine-4-aldehyde benzo [ c ] [1,2,5] thiadiazole; step 2, dissolving the intermediate product, the cholesterol formamidobenzyl cyanide and sodium methoxide in ethanol; and leaching the filter cake with ethanol for 3 times, and drying to obtain red powder, namely the target product. The invention has larger force-induced ratio color change, can be used as a fluorescent pressure sensing probe, and has the following characteristics: the fluorescence efficiency is high (44.3%), the synthesis is simple, the relationship between pressure and emission wavelength can be quantitatively determined, the color change range is large, and the material has great application potential in a pressure sensing system.

Description

A kind of high luminescence mechanochromic material from red to near infrared and preparation method thereof

technical field

The invention belongs to the field of high-luminescence electrochromic materials, in particular to a preparation method of a high-luminescence electrochromic material from red to near-infrared.

Background technique

In recent years, organic near-infrared (680nm-900nm) fluorescent dyes have been widely used in bioimaging, pressure sensing, infrared The fields of camouflage, anti-counterfeiting detection and fluorescence recognition have broad application prospects.

Up to now, many kinds of near-infrared fluorescent probes have been reported. According to their different structures, such materials can be divided into: stilbene nitrile, difluoroboron, tetraphenylene, aromatic acid cyanine, thiocyanate Zine, BODIPY, etc. For example (Chem.Eur.J., 2014, 21, 2474-2479) reported a compound pCN-TPA with stilbene nitrile as the core electron-donating-electron-withdrawing structure, which exhibited at the initial normal pressure The luminescence of 508nm can gradually red-shift to 618nm under the action of static pressure, and the red-shift reaches 110nm, and can return to the initial state after the static pressure is relieved. (Chem. Commun., 2016, 52, 3836-3839) synthesized a cyano-substituted stilbene derivative, CzCNDSB, with an initial emission at 529 nm, which can be red-shifted from 155 nm to 684 nm under the action of external static pressure. A change from green to deep red is achieved, and the luminescence returns to the original state after the static pressure is removed. (Angew.Chem.Int.Ed., 2020,59,15267-15267) Using the co-crystal strategy, the anthracene derivatives and the fluorobenzene derivatives were fumigated with a solvent to obtain a co-crystal. A luminescence of 554 nm is achieved, and it can be red-shifted from 92 nm to 646 nm (green to red transition) under the action of static pressure.

However, there are still relatively few static piezochromic materials with high fluorescence quantum efficiency in the near-infrared region. The key to constructing high-contrast near-infrared deep red to near-infrared discoloration range is the suppression of intermolecular π-π interactions under pressure.

SUMMARY OF THE INVENTION

The present invention aims to solve the problems described in the background art, and provides a preparation method of a highly luminescent mechanochromic material from red to near-infrared.

In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a preparation method of a high luminescence electrochromic material from red to near-infrared, comprising the following steps:

Step 1. Synthesis of intermediate product 7-triphenylamine-4-aldobenzo[c][1,2,5]thiadiazole:

Weigh 7-bromo-4-aldehyde benzo[c][1,2,5]thiadiazole, triphenylamine boric acid, tetrakistriphenylphosphonium palladium and sodium carbonate, and configure the sodium carbonate into a sodium carbonate solution, The above-mentioned raw materials are dissolved in chromatographic toluene and tetrahydrofuran; under the protection of nitrogen atmosphere, the reaction is stirred under reflux, and the reaction process is confirmed by a dot plate when a large number of red solid particles are precipitated, and the reaction is terminated if the reaction is complete; then through extraction, filtration, Column chromatography and rotary evaporation to obtain red powder, namely 7-triphenylamine-4-aldobenzo[c][1,2,5]thiadiazole;

Step 2, the synthesis of target product:

Dissolve the intermediate product, cholesterol carboxamidophenylacetonitrile and sodium methoxide in ethanol; under the protection of nitrogen atmosphere, stir the reaction at 60 °C, and stop the reaction when a large number of solid particles are precipitated; then put the ethanol solution of the product into the refrigerator Carry out cooling and precipitation, and filter after the solid precipitation is complete. The filter cake obtained by filtration is rinsed with ethanol for 3 times, and dried to obtain red powder, that is, the target product.

The target product is a near-infrared light region color-changing dye benzothiadiazole cholesterol carboxamidophenylacetonitrile derivative, the chemical formula is: C ₆₁ H ₆₇ N ₅ O ₂ S.

In a preferred embodiment of the present invention, the molar ratio of 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole to triphenylamineboronic acid is 1:1-1:1.5;7 -Bromo-4-aldehyde benzo[c][1,2,5]thiadiazole: sodium carbonate: toluene: tetrahydrofuran, the dosage ratio is: 10mmol:0.8-1.2mmol:50-60ml:30-40ml, wherein The concentration of the sodium carbonate solution was 3 mol/L.

In a preferred embodiment of the present invention, in step 1, the reflux stirring reaction time is 12-24 h, and the reaction temperature is 80-100°C.

In a preferred embodiment of the present invention, the extraction solution is dichloromethane, and the eluents separated by column chromatography are petroleum ether and dichloromethane.

In a preferred embodiment of the present invention, in step 2, the molar ratio of cholesterol formamidophenylacetonitrile to the intermediate product is 1:1-1:1.3; cholesterol formamidophenylacetonitrile: sodium methoxide: chromatographic ethanol is 3mmol: 0.3-0.6 mmol: 30-50 ml.

In a preferred embodiment of the present invention, in step 2, the stirring reaction time is 10-12h.

In a preferred embodiment of the present invention, in step 2, the temperature in the refrigerator is -10-0° C., and the time for placing in the refrigerator is 2-3 hours.

In a preferred embodiment of the present invention, in step 2, the volume molar ratio of ethanol to cholesterol carboxamidophenylacetonitrile used for each rinse is 2:1, and the number of rinses is 3-6 times.

In a preferred embodiment of the present invention, a red to near-infrared high luminescence mechanochromic material prepared by the method of any one of claims 1-8 is applied to a pressure detection material.

The principle of the present invention and its beneficial effects: the static pressure-induced proportional discoloration material provided by the present invention has the characteristics of obvious color change (red becomes near-infrared) and good sensitivity to external stimuli. Color changes ratiometrically and can be used in pressure sensing elements and optical recording.

Molecules form unique dimer packings when they aggregate, and unconjugated cholesterol can inhibit the strong π-π interactions between molecules during the tight packing process.

Compared with the prior art, most of the near-infrared fluorescent molecules have low fluorescence efficiency and complex synthesis. The near-infrared fluorescent molecules of the present invention have high fluorescence efficiency (44.3%), produce a 157nm spectral red shift, and are simple to synthesize, which will greatly enhance the synthesis. Application potential of materials in the field of pressure detection.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is the fluorescence spectrum of the near-infrared benzothiadiazole cholesterol carboxamidophenylacetonitrile-based fluorescent dye static pressure-induced ratiochromatism under the pressure of 0atm-2.0GPa;

Fig. 2 is the fluorescence spectrum of the near-infrared benzothiadiazole cholesterol carboxamidophenylacetonitrile-based fluorescent dye static pressure-induced ratiochromaticity under the pressure of 2.6-7GPa;

Figure 3 is a graph showing the relationship between the static pressure and the spectrum of the near-infrared benzothiadiazole cholesterol carboxamidophenylacetonitrile fluorescent dye of the present invention.

Figure 4 is the unique dimer packing formed by the molecules.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present invention, and should not be construed as a limitation of the present invention.

In the description of the present invention, it should be understood that the terms "portrait", "horizontal", "vertical", "upper", "lower", "front", "rear", "left", "right", The orientation or positional relationship indicated by "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and to simplify the description rather than to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a mechanical connection or an electrical connection, or two The internal communication between the elements may be directly connected or indirectly connected through an intermediate medium, and those of ordinary skill in the art can understand the specific meanings of the above terms according to specific circumstances.

The present application provides a method for preparing a highly luminescent mechanochromic material from red to near-infrared, comprising the following steps:

Step 1. Synthesis of intermediate (II) 7-triphenylamine-4-aldobenzo[c][1,2,5]thiadiazole:

Its synthetic route is as follows:

The specific operation is as follows: Weigh 7-bromo-4-aldehyde benzo[c][1,2,5]thiadiazole, triphenylamine boronic acid, tetrakistriphenylphosphonium palladium and sodium carbonate, and configure the sodium carbonate into Sodium carbonate aqueous solution, the above raw materials are dissolved in chromatographic toluene and tetrahydrofuran, wherein, 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole (III) and triphenylamineboronic acid (IV) The molar ratio of 1:1-1:1.5; 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole: sodium carbonate: chromatographic toluene: chromatographic tetrahydrofuran 10mmol: 0.8-1.2 mmol: 50-60ml: 30-40ml; under the protection of nitrogen atmosphere, the reaction time of reflux stirring is 12-24h, when a large number of red solid particles are precipitated, the reaction process is confirmed by the dot plate, and the reaction is terminated when it is confirmed that the reaction is basically completed; then The reaction solution was extracted and filtered, separated by silica gel column chromatography, rinsed with petroleum ether:dichloromethane=2:1, and rotary-evaporated under reduced pressure to obtain a red powder, which was the product intermediate (II);

Step 2, the synthesis of target product (I):

Its synthetic route is as follows:

The specific operation is as follows: Weigh intermediate (II), cholesterol formamidophenylacetonitrile (V) and sodium methoxide and dissolve them in chromatographic ethanol, wherein the molar ratio of cholesterol formamidophenylacetonitrile (V) to intermediate (II) It is 1:1-1:1.3; cholesterol formamidophenylacetonitrile (V): sodium methoxide: chromatographic ethanol is 3mmol:0.3-0.6mmol:30-50ml. Under the protection of nitrogen atmosphere, the reaction was stirred at 60 °C for 8-12 hours, and the reaction was terminated when a large number of solid particles were precipitated; then the reaction system was placed in a -20-0 °C refrigerator for 8-10 hours, and then the filter cake was filtered, and the filter cake was filtered with ethanol. Rinse 3-6 times, the volume molar ratio (L/mol) of ethanol and cholesterol carboxamidophenylacetonitrile for each rinse is 2:1, after drying, a red powder is obtained, that is, the target product benzothiadiazole Cholesterol carboxamidophenylacetonitrile derivative (I). Among them, (I) molecular weight 933.5g/mol; (II) molecular weight 407g/mol; (V) molecular weight 544g/mol;

The feeding ratio of substances (II) and (V) is controlled at 1:1 or (II) is slightly excessive, but not more than 1:1.3; the control range of the amount of catalyst sodium methoxide is: cholesterol formamidophenylacetonitrile (V): sodium methoxide= 1 mmol: 0.1-0.2 mmol. Many near-infrared fluorescent molecules have been reported before. These molecules generally have low fluorescence quantum efficiency and have complex synthesis problems. However, the target molecule in the present invention has high fluorescence quantum efficiency and is simple to synthesize, which greatly increases the efficiency of synthesis. Great application potential as a pressure sensing system.

The experimental method is as follows:

Experiment 1

Step 1. Synthesis of intermediate (II): Weigh 1.3 g (6 mmol) of 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole (III), triphenylamine boronic acid (IV) ) 1.8g (6.2mmol), tetrakistriphenylphosphonium palladium 0.25g (0.22mmol) and sodium carbonate solution (3mol/L) were dissolved in chromatography toluene (50ml) and tetrahydrofuran (30ml), under nitrogen atmosphere protection, 80 The reaction time was 12 h under reflux stirring at ℃. When a large number of red solid particles were precipitated, the reaction process was determined and the reaction was terminated. All the crude products after the reaction were dissolved in dichloromethane, transferred, washed with water, and the organic phase was taken, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. , the 1:2 ratio of dichloromethane and petroleum ether was used as the eluent to carry out column chromatography separation, and a total of 1.68 g of the product intermediate (II) was obtained with a yield of 70%.

Step 2. Weigh 0.2 g (0.55 mmol) of intermediate (II), 0.31 g (0.55 mmol) of cholesterol carboxamidophenylacetonitrile (V) and 0.054 g (1 mmol) of sodium methoxide and dissolve them in 40 ml of chromatographic ethanol. Under the protection of nitrogen atmosphere, the reaction was stirred at 60 °C for 10 h, and the reaction was terminated when a large number of solid particles were precipitated. Then put the ethanol solution of the product into a -10°C refrigerator for 2 hours, and filter after the solid precipitation is complete. The filter cake obtained by filtration is rinsed with ethanol (20mL×3) times, and dried to obtain a total of 0.30g of red powder. The rate was 63.6%. , namely the target product benzothiadiazole cholesterol carboxamidophenylacetonitrile derivative (I).

Characterization data are as follows: ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.72 (d, J=7.6 Hz, 1H), 8.49 (s, 1H), 7.94 (d, J=8.8 Hz, 2H), 7.84 (d, J=7.6Hz,1H),7.79(d,J=8.8Hz,2H),7.54(d,J=8.8Hz,2H),7.34(t,J=8.4Hz,4H),7.23(m,6H) ,7.11(t,J=7.6Hz,2H),6.77(s,1H),5.44(d,J=4.8Hz,1H),4.67(m,1H),2.41(m,2H),1.61(m, 12H), 1.36(m, 3H), 1.16(m, 8H), 1.07(m, 6H), 0.94(d, J=6.4Hz, 3H), 0.89(dd, J=2.0Hz, J=1.6Hz, 6H), 0.71 (s, 3H); [M]+934.4986.

Experiment 2

Step 1. Synthesis of intermediate (II): Weigh 2.11 g (10 mmol) of 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole (III), triphenylamine boronic acid (IV) ) 2.89g (10mmol), tetrakistriphenylphosphonium palladium 0.25g (0.22mmol) and sodium carbonate solution (3mol/L) were dissolved in chromatography toluene (50ml) and tetrahydrofuran (30ml), under the protection of nitrogen atmosphere, 100 ℃ The reaction time of reflux stirring was 20h. When a large number of red solid particles were precipitated, the reaction process was determined and the reaction was terminated. All the crude products after the reaction were dissolved in dichloromethane, transferred, washed with water, and the organic phase was taken, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. , using the ratio of dichloromethane and petroleum ether 1:2 as the eluent to carry out column chromatography separation to obtain the product intermediate (II), a total of 3.2 g, with a yield of 78.6%.

Step 2. Weigh 0.795 g (1.95 mmol) of intermediate (II), 0.816 g (1.5 mmol) of cholesterol carboxamidophenylacetonitrile (V) and 0.008 g (0.15 mmol) of sodium methoxide and dissolve them in 50 ml of chromatographic ethanol. Under the protection of nitrogen atmosphere, the reaction was stirred at 60 °C for 10 h, and the reaction was terminated when a large number of solid particles were precipitated. Then put the ethanol solution of the product into the refrigerator at 0°C for 3 hours, and filter after the solid precipitation is complete. The filter cake obtained by filtration is rinsed with ethanol (20 mL×5) times, and dried to obtain a total of 1.1 g of red powder. The yield is 1.1 g. was 89.1%. , namely the target product benzothiadiazole cholesterol carboxamidophenylacetonitrile derivative (I).

Experiment 3

Step 1. Synthesis of intermediate (II): Weigh 1.06 g (5 mmol) of 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole (III), triphenylamine boronic acid (IV) ) 1.70g (7.5mmol), tetrakistriphenylphosphonium palladium 0.25g (0.22mmol) and sodium carbonate solution (3mol/L) were dissolved in chromatography toluene (60ml) and tetrahydrofuran (40ml), under nitrogen atmosphere protection, 90 The reaction time was 20 h under reflux stirring at ℃. When a large number of red solid particles were precipitated, the reaction process was determined by the dot plate, and the reaction was terminated. All the crude products after the reaction were dissolved in dichloromethane, transferred, washed with water, and the organic phase was taken, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. In the 1:2 ratio of dichloromethane and petroleum ether as eluent for column chromatography separation, a total of 1.65 g of product intermediate (II) can be obtained with a yield of 80.5%.

Step 2. Weigh 0.619 g (1.52 mmol) of intermediate (II), 0.4265 g (1.5 mmol) of cholesterol carboxamidophenylacetonitrile (V) and 0.016 g (0.3 mmol) of sodium methoxide and dissolve them in 40 ml of chromatographic ethanol. Under the protection of nitrogen atmosphere, the reaction was stirred at 60 °C for 11 h, and the reaction was terminated when a large number of solid particles were precipitated. Then put the ethanol solution of the product into a -20°C refrigerator for 10 hours to cool and separate out, and filter after the solid precipitation is complete. The filter cake obtained by filtration is rinsed with ethanol (20mL×4) times, and dried to obtain a red powder with a total of 1.02 g, the yield is 73%. , namely the target product benzothiadiazole cholesterol carboxamidophenylacetonitrile derivative (I).

Experiment 4

Step 1. Synthesis of intermediate (II): Weigh 2.11 g (10 mmol) of 7-bromo-4-aldobenzo[c][1,2,5]thiadiazole (III), triphenylamine boronic acid (IV) ) 2.92g (10.1mmol), tetrakistriphenylphosphonium palladium 0.25g (0.22mmol) and sodium carbonate solution (3mol/L) were dissolved in chromatography toluene (55ml) and tetrahydrofuran (40ml), under the protection of nitrogen atmosphere, 95 The reaction time under reflux stirring at ℃ is 24h. When a large number of red solid particles are precipitated, the reaction process is determined and the reaction is terminated. All the crude products after the reaction were dissolved in dichloromethane, transferred, washed with water, and the organic phase was taken, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. , using the ratio of dichloromethane and petroleum ether 1:2 as the eluent to carry out column chromatography separation to obtain a total of 3.4 g of the product intermediate (II) with a yield of 76%.

Step 2. Weigh 0.619 g (1.52 mmol) of intermediate (II), 0.816 g (1.5 mmol) of cholesterol carboxamidophenylacetonitrile (V) and 0.054 g (1 mmol) of sodium methoxide and dissolve them in 30 ml of chromatographic ethanol. Under the protection of nitrogen atmosphere, the reaction was stirred at 60 °C for 12 h, and the reaction was terminated when a large number of solid particles were precipitated. Then put the ethanol solution of the product into a -10°C refrigerator for 10 hours, and filter after the solid precipitation is complete. The filter cake obtained by filtration was rinsed with ethanol (20mL×6) times, and dried to obtain a total of 0.954g of red powder. The rate was 68.0%. , namely the target product benzothiadiazole cholesterol carboxamidophenylacetonitrile derivative (I).

The target product benzothiadiazole cholesterol carboxamidophenylacetonitrile derivative (I) obtained from the above experiment mode 1 to experimental mode 4, as shown in Figure 4, the molecule forms a unique dimer stacking, in n-hexane. The red flaky crystals were obtained by solvent volatilization in the mixed solution of /tetrahydrofuran, and the emission spectra under different pressures were explored, and the relationship between the intensity and wavelength of the fluorescence emission spectrum and the static pressure was roughly clarified, as shown in Figure 1 and Figure 2 Shown: The crystal can emit fluorescence from red to near-infrared. With the increase of pressure, the fluorescence intensity decreases continuously, and the color of fluorescence gradually changes from red to near-infrared. This phenomenon indicates that the material could be used in the field of pressure sensors or information storage. In addition, the spectrum is processed to obtain the position of the luminescence peak, and the relationship between the static pressure and the peak position of the fluorescence emission spectrum is obtained by linear fitting, as shown in Figure 3: in the process of gradually increasing the static pressure, the luminescence of the red crystal gradually becomes red. The light-emitting position has a certain linear relationship with the static pressure. The relationship between the pressure and the spectrum is 22.1nm/GPa, and the wavelength changes by 157nm. The material can be used for pressure sensing elements.

To sum up, the static pressure-induced proportional color changing material provided by the present invention has obvious color change (as shown in Figure 3, at 1 atm-7 Gpa, with the increase of pressure, the wavelength red-shifts from 650nm to 806nm, and the red-shift reaches 156nm, by Red changes to near-infrared, so the color changes obviously), and it is sensitive to external stimuli (it can be seen from the spectrograms in Figures 1 and 2 that with the increase of pressure, the fluorescence intensity decreases significantly). It applies static pressure to ratiometrically change its color and can be used in pressure sensing elements and optical recording.

Most of the near-infrared fluorescent molecules have low fluorescence efficiency and complex synthesis. The near-infrared fluorescent molecules of the present invention have high fluorescence efficiency (44.3%) and simple synthesis, which greatly increases the huge application potential as a pressure sensing system.

In the description of this specification, reference to the terms "preferred embodiment," "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., is intended to incorporate the embodiment. A particular feature, structure, material, or characteristic described or exemplified is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. A preparation method of a high-luminous-power photochromic material from red to near infrared is characterized by comprising the following steps:

step 1, synthesizing an intermediate product 7-triphenylamine-4-aldehyde benzo [ c ] [1,2,5] thiadiazole:

weighing 7-bromo-4-aldehyde benzo [ c ] [1,2,5] thiadiazole, triphenylamine boric acid, tetratriphenylphosphine palladium and sodium carbonate, preparing sodium carbonate into a sodium carbonate solution, and dissolving the raw materials in chromatographic toluene and tetrahydrofuran; under the protection of nitrogen atmosphere, carrying out reflux stirring reaction, confirming the reaction process by a point plate when a large amount of red solid particles are separated out, and stopping the reaction if the reaction is complete; then extracting, filtering, separating by column chromatography and rotary evaporating to obtain red powder, namely the 7-triphenylamine-4-aldehyde benzo [ c ] [1,2,5] thiadiazole;

step 2, synthesis of a target product:

dissolving the intermediate product, cholesterol formamido benzyl cyanide and sodium methoxide in ethanol; stirring and reacting at 60 ℃ under the protection of nitrogen atmosphere, and stopping the reaction when a large amount of solid particles are separated out; and then, cooling and separating out the ethanol solution of the product in a refrigerator, filtering after the solid is completely separated out, leaching the filter cake obtained by filtering for 3 times by using ethanol, and drying to obtain red powder, namely a target product, wherein the target product is the near-infrared region color-changing dye benzothiadiazole cholesterol formamido benzyl cyanide derivative.

2. The method of claim 1, wherein the molar ratio of 7-bromo-4-formylbenzo [ c ] [1,2,5] thiadiazole to triphenylamine boronic acid is 1:1 to 1: 1.5; 7-bromo-4-formylbenzo [ c ] [1,2,5] thiadiazole: sodium carbonate: toluene: the dosage ratio of the tetrahydrofuran is as follows: 0.8-1.2mmol of 10-60 ml of 50-60ml of 30-40ml of 10mmol, wherein the concentration of the sodium carbonate solution is 3 mol/L.

3. The method for preparing a high luminous power of red to near infrared photochromic material of claim 2 wherein in step 1, the reaction time is 12-24 hours under reflux and stirring, and the reaction temperature is 80-100 ℃.

4. The method of claim 3, wherein the extraction liquid is dichloromethane and the eluent for column chromatography is petroleum ether and dichloromethane.

5. The method for preparing a high luminous power chromic material from red to near infrared as claimed in claim 4 wherein, in the step 2, the molar ratio of the cholesterylaminobenzylcyanide to the intermediate product is 1:1 to 1: 1.3; cholesterol formamidophenylacetonitrile: sodium methoxide: chromatographic ethanol is 3mmol, 0.3-0.6mmol, 30-50 ml.

6. The method for preparing a high luminous power chromic material from red to near infrared as claimed in claim 5 wherein, in the step 2, the stirring reaction time is 10-12 h.

7. The method for preparing a high luminous power chromic material from red to near infrared as claimed in claim 6 wherein, in the step 2, the temperature in the refrigerator is-10-0 ℃ and the time of putting into the refrigerator is 2-3 h.

8. The method for preparing a red to near-infrared high luminous force electrochromic material according to claim 7, wherein in the step 2, the volume molar ratio of ethanol to cholesterol formamidophenylacetonitrile used for each elution is 2:1, and the elution times are 3 to 6.

9. C prepared by the method of any one of claims 1 to 8₆₁H₆₇N₅O₂S。

10. A high luminous power chromic material from red to near infrared prepared by the method of any one of claims 1 to 8 applied to a pressure detecting material.

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