A DASA compound, its preparation method, and its application in photochromic dyes

Abstract

The application discloses a DASA compound, a preparation method thereof and application of the DASA compound in photochromic dyes, and relates to the technical field of photochromic materials. The DASA compound is a non-linear DASA molecule. Due to the unique molecular structure and the space and electronic structure regulation effect brought by the unique molecular structure, the DASA compound is synergized with the interaction of a polymer matrix, so that the DASA compound has more excellent photochromic performance, the photochromic rate and the thermal recovery rate are faster, and the anti-fatigue property in the polymer matrix is better. The DASA compound can be widely applied to the preparation of photochromic dyes.

Description

Technical Field

[0001] This invention relates to the field of photochromic materials technology, and more specifically, to a DASA compound, its preparation method, and its application in photochromic dyes. Background Technology

[0002] Donor-acceptor Stenhouse adducts (DASAs) are a novel type of photochromic compound that has attracted widespread attention and research since their first report in 2014. Conventional DASA molecules have a linear structure, primarily composed of an electron donor and an electron acceptor linked by a trienol structure. This colored trienol structure transforms into a colorless cyclic form upon absorbing visible light of a certain wavelength; this process is the most important photochromic process and the underlying principle of DASA compounds. Simultaneously, the colorless cyclic structure obtained through the photochromic process can undergo a reverse process under thermal influence, reverting from the cyclic structure back to the trienol structure; this process is the thermal coloring process of DASA molecules. By adjusting the donor and acceptor structures that make up the DASA molecule, its light absorption and photochromic properties can be modified, thus leading to a diverse range of structures, properties, and applications for DASA molecules.

[0003] However, most existing DASA compounds can only exhibit reasonably high photochromic and thermal recovery rates in solution, and cannot demonstrate high-speed photofading, thermal recovery, and excellent fatigue resistance in polymer matrices.

[0004] The prior art discloses a DASA-type compound and its synthesis method. The DASA-type compound is 5-((2Z,4E)-5-(benzyl(ethyl)amino)-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, with the following structural formula: This DASA compound addresses the response of DASA compounds to acids and bases and their effect on Cu. 2+ It showed a responsive effect, but did not improve the light fading or thermal recovery rate of DASA compounds in the polymer matrix, nor did it enhance the fatigue resistance of DASA compounds. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of existing DASA photochromic materials in polymer matrices, such as slow light fading and thermal recovery, and poor fatigue resistance. The present invention provides a DASA compound that, through the regulation of molecular structure and spatial and electronic structure, has the ability to rapidly undergo photochromic and thermal recovery processes in solution and polymer matrix, and has good fatigue resistance.

[0006] Another object of the present invention is to provide a method for preparing DASA compounds.

[0007] Another object of the present invention is to provide an application of DASA compounds in the preparation of photochromic dyes.

[0008] Another object of the present invention is to provide a photochromic dye.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] A DASA compound with the following structural formula:

[0011]

[0012] Where n = 0, 1, 2, 3, R1 is methyl, ethyl, propyl or butyl, and m = 1, 2, 3.

[0013] in, It can be any of the following:

[0014]

[0015] In specific embodiments, the DASA compound of the present invention can be any of the following DASA compounds:

[0016]

[0017]

[0018] The DASA compounds of this invention are nonlinear, comprising dendritic, star-shaped, and multi-branched DASA molecules. Due to their unique molecular structure and the resulting spatial and electronic structure regulation effects, they synergistically interact with the polymer matrix, resulting in superior photochromic properties, including but not limited to photochromic rate, thermal recovery rate, and fatigue resistance. This achieves the beneficial effect of significantly improving the photochromic performance of DASA photochromic compounds without substantially increasing the design and synthesis costs of DASA.

[0019] In the specific DASA compound described above, more preferably, the DASA compound can be any one of the following DASA compounds:

[0020]

[0021] The aforementioned DASA compounds exhibit faster photochromic and thermal recovery processes in both solution and polymer matrices, and also demonstrate better fatigue resistance.

[0022] This invention also specifically protects a method for preparing a DASA compound, comprising the following steps:

[0023] The donor and acceptor molecules were mixed and dissolved in a dichloromethane / hexafluoroisopropanol mixed solvent. The mixture was then reacted in the dark, and the resulting purified compound was obtained.

[0024] The reaction temperature of the present invention can be from -4°C to 39.8°C, preferably at room temperature of 25°C.

[0025] The reaction pressure of the present invention can be 1 to 6 atmospheres, and the reaction is preferably carried out under stirring with a stirring speed of 50 to 1500 rpm.

[0026] The reaction gas atmosphere of the present invention can be air, argon, oxygen, nitrogen, etc., and the relative humidity of the reaction atmosphere air can be 0 to 100% RH.

[0027] The reaction time of this invention can be 8 to 48 hours to ensure complete reaction.

[0028] The crude DASA compound solution prepared by the present invention is subjected to vacuum distillation to remove the solvent, followed by washing with solvent and collection of the precipitate to obtain purified DASA compound.

[0029] The washing solvent can be diethyl ether, petroleum ether, n-hexane, cyclohexane, etc., and the precipitate can be collected using conventional methods in the field, such as filtration, centrifugation, etc.

[0030] The molar ratio of donor to acceptor molecules is ≤1:3 to ensure that the three reaction sites in the donor molecule react completely with the acceptor molecule.

[0031] Preferably, the donor molecule is an aromatic alkylamine molecule, and the acceptor molecule is a furanaldehyde adduct molecule.

[0032] The donor molecules of this invention spatially increase the induced free volume of the molecules in the matrix; in terms of electronic structure, the several donor molecules used have special star-shaped structures, which play a role in dispersing the electron cloud density and reducing the isomerism energy barrier.

[0033] In the preparation method of the present invention, aromatic alkylamine molecules are used as building units (donor molecules) for the electron donor part in the basic molecular structure of the novel DASA compound, and furanaldehyde adduct molecules are used as building units (acceptor molecules) for the electron acceptor and trienol parts in the basic molecular structure of the novel DASA compound. The molar ratio of donor molecules to acceptor molecules is ≤1:3, dissolved in a mixed solvent of dichloromethane / hexafluoroisopropanol, and reacted at room temperature in the dark for a certain period of time. After purification, the novel DASA compound is obtained.

[0034] In specific embodiments, the donor molecule of the present invention can be any of the following:

[0035]

[0036] Where n = 0, 1, 2, 3, R is methyl, ethyl, propyl or butyl, and m = 1, 2, 3.

[0037] In specific embodiments, the receptor molecule of the present invention can be any of the following:

[0038]

[0039] In a specific embodiment, the molar ratio of donor molecule to acceptor molecule in this invention is 1:3 to 10.

[0040] For example, the molar ratio of donor molecule to acceptor molecule is 1:3;

[0041] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:4;

[0042] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:5;

[0043] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:6;

[0044] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:7;

[0045] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:8;

[0046] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:9;

[0047] Alternatively, the molar ratio of donor molecules to acceptor molecules may be 1:10.

[0048] More preferably, the molar ratio of donor molecule to acceptor molecule is 1:5.

[0049] In a specific embodiment, the volume ratio of dichloromethane to hexafluoroisopropanol in the preparation method of the present invention is 1 to 9:1, for example, it can be:

[0050] The volume ratio of dichloromethane to hexafluoroisopropanol is 1:1;

[0051] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 2:1;

[0052] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 3:1;

[0053] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 4:1;

[0054] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 5:1;

[0055] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 6:1;

[0056] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 7:1;

[0057] Or the volume ratio of dichloromethane to hexafluoroisopropanol is 8:1;

[0058] Alternatively, the volume ratio of dichloromethane to hexafluoroisopropanol may be 9:1.

[0059] More preferably, the volume ratio of dichloromethane to hexafluoroisopropanol is 4:1.

[0060] This invention also specifically protects the use of any of the above-mentioned DASA compounds in the preparation of photochromic dyes.

[0061] The present invention also specifically protects a photochromic dye, including any of the above-mentioned DASA compounds.

[0062] Compared with the prior art, the beneficial effects of the present invention are:

[0063] The DASA compound of this invention is a linear, dipolar DASA molecule. Due to its unique molecular structure and the resulting spatial and electronic structure regulation effect, it exhibits superior photochromic properties, with faster photochromic rate and thermal recovery rate, and better fatigue resistance. The DASA compound of this invention can be widely used in the preparation of photochromic dyes. Attached Figure Description

[0064] Figure 1 The 1H NMR spectrum of the DASA compound in Example 1 is shown.

[0065] Figure 2 The 1H NMR spectrum of the DASA compound in Example 2.

[0066] Figure 3 The 1H NMR spectrum of the DASA compound in Example 3 is shown.

[0067] Figure 4 The 1H NMR spectrum of the DASA compound in Example 4 is shown.

[0068] Figure 5 The 1H NMR spectrum of the DASA compound in Example 5 is shown.

[0069] Figure 6 The 1H NMR spectrum of the DASA compound in Example 6 is shown.

[0070] Figure 7 The 1H NMR spectrum of the DASA compound in Example 7 is shown.

[0071] Figure 8 The 1H NMR spectrum of the DASA compound in Example 8 is shown.

[0072] Figure 9 The 1H NMR spectrum of the DASA compound in Example 9 is shown.

[0073] Figure 10 The 1H NMR spectrum of the DASA compound in Example 10 is shown.

[0074] Figure 11 The 1H NMR spectrum of the DASA compound in Example 11 is shown.

[0075] Figure 12 The 1H NMR spectrum of the DASA compound in Example 12 is shown.

[0076] Figure 13 The 1H NMR spectrum of the DASA compound in Comparative Example 1 is shown. Detailed Implementation

[0077] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0078] Example 1

[0079] A DASA compound,

[0080]

[0081] The preparation method is as follows:

[0082] Step 1: Dissolve the donor molecule 1,3,5-tris(4-N-methylaminophenyl)benzene (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 2,2-diethyl-5-(2-furanylmethylene)-1,3-dioxane-4,6-dione (95 mg, 0.38 mmol, 5 eq) in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. Stir the mixed solution in the dark at a certain temperature for 24 hours to obtain a crude product solution of the first new DASA compound.

[0083] The molar ratio of donor molecules to acceptor molecules is 1:5.

[0084] Step 2: After removing the solvent from the crude product solution of the new DASA compound obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a purple-red suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 79 mg of purple powder, which is the new DASA compound with the first structure, with a yield of 91%.

[0085]

[0086] The structure of the product is obtained from the proton NMR spectrum, such as Figure 1 .

[0087] Example 2

[0088] A DASA compound,

[0089]

[0090] The preparation method is as follows:

[0091] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)benzene (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 5-(2-furanmethyl)-1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione (89 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the second novel DASA compound.

[0092] The molar ratio of donor to acceptor molecules is 1:5.

[0093] Step 2: After removing the solvent from the crude product solution of the new DASA compound obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a dark purple suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 60 mg of dark purple powder, which is the new DASA compound, with a yield of 72%.

[0094]

[0095] The structure of the product is obtained from the proton NMR spectrum, such as Figure 2 .

[0096] Example 3

[0097] A DASA compound,

[0098]

[0099] The preparation method is as follows:

[0100] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)benzene (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 4-(2-furanmethyl)-2,4-dihydro-2-phenyl-5-(trifluoromethyl)-3H-pyrazol-3-one (117 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound No. 3.

[0101] The molar ratio of donor molecules to acceptor molecules is 1:5.

[0102] Step 2: After removing the solvent from the crude product solution of the new DASA compound No. 3 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a blue suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 85 mg of blue powder, which is the new DASA compound No. 3, with a yield of 85%.

[0103]

[0104] The structure of the product is obtained from the proton NMR spectrum, such as Figure 3 .

[0105] Example 4

[0106] A DASA compound,

[0107]

[0108] The preparation method is as follows:

[0109] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)benzene (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 4-(2-furanmethyl)-3-(trifluoromethyl)-5(4H)-isoxazolone (88 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound with the fourth structure.

[0110] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0111] Step 2: After removing the solvent from the crude product solution of the new DASA compound No. 4 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a dark blue suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 48 mg of dark blue powder, which is the new DASA compound No. 4, with a yield of 58%.

[0112]

[0113] The structure of the product is obtained from the proton NMR spectrum, such as Figure 4 .

[0114] Example 5

[0115] A DASA compound,

[0116]

[0117] The preparation method is as follows:

[0118] Step 1: The donor molecule 1,3,5-tris(4-N-ethylaminophenyl)benzene (30 mg, 0.069 mmol, 1 eq) and the acceptor molecule 2,2-diethyl-5-(2-furanylmethylene)-1,3-dioxane-4,6-dione (86.3 mg, 0.345 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound (structure 5).

[0119] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0120] Step 2: After removing the solvent from the crude product solution of the new DASA compound No. 5 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a purple-red suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 70 mg of purple-red powder, which is the new DASA compound No. 5, with a yield of 81%.

[0121]

[0122] The structure of the product is obtained from the proton NMR spectrum, such as Figure 5 .

[0123] Example 6

[0124] A DASA compound,

[0125]

[0126] The preparation method is as follows:

[0127] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)triazine (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 4-(2-furanmethyl)-2,4-dihydro-2-phenyl-5-(trifluoromethyl)-3H-pyrazol-3-one (117 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound with the sixth structure.

[0128] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0129] Step 2: After removing the solvent from the crude product solution of the new DASA compound with the sixth structure obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a blue suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 85 mg of green powder, which is the new DASA compound with the sixth structure, with a yield of 85%.

[0130]

[0131] The structure of the product is obtained from the proton NMR spectrum, such as Figure 6 .

[0132] Example 7

[0133] A DASA compound,

[0134]

[0135] The preparation method is as follows:

[0136] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)benzene (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 1-ethyl-5-(2-furanmethylene)-1,2,5-6-tetrahydro-4-methyl-2,6-dioxo-3-pyridinium nitrile (97 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound with the seventh structure.

[0137] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0138] Step 2: After removing the solvent from the crude product solution of the new DASA compound with the seventh structure obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a black suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 65 mg of dark green powder, which is the new DASA compound with the seventh structure, with a yield of 74%.

[0139]

[0140] The structure of the product is obtained from the proton NMR spectrum, such as Figure 7 .

[0141] Example 8

[0142] A DASA compound,

[0143]

[0144] The preparation method is as follows:

[0145]

[0146] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)triazine (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 2,2-diethyl-5-(2-furanylmethylene)-1,3-dioxane-4,6-dione (95 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound No. 8.

[0147] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0148] Step 2: After removing the solvent from the crude product solution of the new DASA compound No. 8 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a purple-red suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 75 mg of gray powder, which is the new DASA compound No. 8, with a yield of 86%.

[0149] The structure of the product is obtained from the proton NMR spectrum, such as Figure 8 .

[0150] Example 9

[0151] A DASA compound,

[0152]

[0153] The preparation method is as follows:

[0154]

[0155] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)triazine (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 5-(2-furanmethyl)-1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione (89 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the new DASA compound with the ninth structure.

[0156] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0157] Step 2: After removing the solvent from the crude product solution of the new DASA compound with the new structure obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain an indigo blue suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 69 mg of blue powder, which is the new DASA compound with the new structure, with a yield of 83%.

[0158] The structure of the product is obtained from the proton NMR spectrum, such as Figure 9 .

[0159] Example 10

[0160] A DASA compound,

[0161]

[0162] The preparation method is as follows:

[0163]

[0164] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)amine (25 mg, 0.076 mmol, 1 eq) and the acceptor molecule 2,2-diethyl-5-(2-furanylmethylene)-1,3-dioxane-4,6-dione (95 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the novel DASA compound No. 10.

[0165] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0166] Step 2: After removing the solvent from the crude product solution of the new DASA compound No. 10 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a purplish-black suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 72 mg of black powder, which is the new DASA compound No. 10, with a yield of 88%.

[0167]

[0168] The structure of the product is obtained from the proton NMR spectrum, such as Figure 10 .

[0169] Example 11

[0170] A DASA compound,

[0171]

[0172] The preparation method is as follows:

[0173]

[0174] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)amine (25 mg, 0.076 mmol, 1 eq) and the acceptor molecule 4-(2-furanmethyl)-2,4-dihydro-2-phenyl-5-(trifluoromethyl)-3H-pyrazol-3-one (117 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the novel DASA compound No. 11.

[0175] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0176] Step 2: After removing the solvent from the crude product solution of the DASA compound with the new structure No. 11 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a blue-black suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 86 mg of black powder, which is the DASA compound with the new structure No. 11, with a yield of 91%.

[0177] The structure of the product is obtained from the proton NMR spectrum, such as Figure 11 .

[0178] Example 12

[0179] A DASA compound,

[0180]

[0181] The preparation method is as follows:

[0182]

[0183] Step 1: The donor molecule 1,3,5-tris(4-N-methylaminophenyl)benzene (30 mg, 0.076 mmol, 1 eq) and the acceptor molecule 2-(2-furanmethyl)-1H-inden-1,3(2H)-dione (85 mg, 0.38 mmol, 5 eq) were dissolved in a mixed solvent of 3 mL dichloromethane and 0.75 mL hexafluoroisopropanol. The mixture was stirred in the dark at a certain temperature for 24 hours to obtain a crude product solution of the novel DASA compound No. 12.

[0184] The molar ratio of donor molecules to acceptor molecules is 1:5;

[0185] Step 2: After removing the solvent from the crude product solution of the new DASA compound No. 12 obtained in Step 1 by vacuum distillation, 20 ml of anhydrous diethyl ether was added, and the mixture was stirred for 1 hour at room temperature in the dark to obtain a black suspension. The suspension was filtered and the precipitate was collected. The precipitate was washed with diethyl ether to obtain 55 mg of black powder, which is the new DASA compound No. 12, with a yield of 68%.

[0186] The structure of the product is obtained from the proton NMR spectrum, such as Figure 12 .

[0187] Comparative Example 1

[0188] A DASA compound.

[0189]

[0190] Step 1: Dissolve the donor molecule 4-N-methylphenylamine (51.4 mg, 0.458 mmol, 1.3 eq) and the acceptor molecule 2,2-diethyl-5-(2-furanylmethylene)-1,3-dioxane-4,6-dione (95 mg, 0.38 mmol, 1 eq) in a mixed solvent of 2 mL dichloromethane and 0.5 mL hexafluoroisopropanol. Stir the mixed solution in the dark for 12 hours at a certain temperature to obtain a comparative example crude product solution of DASA compound.

[0191] The molar ratio of donor to acceptor molecules is 1.3:1.

[0192] Step 2: After removing the solvent from the crude DASA compound solution obtained in Step 1 by vacuum distillation, add 0.5 ml of tetrahydrofuran and 75 ml of n-hexane, stir overnight at room temperature in the dark to obtain a purple-red suspension, filter and collect the precipitate, wash the precipitate with diethyl ether to obtain 103 mg of purple powder, which is the new DASA compound with a yield of 75.8%.

[0193] The structure of the product is obtained from the proton NMR spectrum, such as Figure 13 .

[0194] Comparative Example 2

[0195] A DASA compound,

[0196]

[0197] Preparation based on existing technology: Donor–Acceptor Stenhouse Adduct-Polydimethylsiloxane-Conjugates for Enhanced Photoswitching in Bulk Polymers, Macromol. RapidComm. 2022, 43, 2200120.

[0198] Comparative Example 3

[0199] A DASA compound,

[0200]

[0201] Preparation based on existing technology: Visible light-responsive DASA-polymer conjugates, ACS Macro Lett. 2017, 6, 738.

[0202] Comparative Example 4

[0203] A DASA compound,

[0204]

[0205] Based on existing technology: Visible light triggered aggregation-induced emissions witching with a donor-acceptor Stenhouse adduct, J. Mater. Chem. C 2018, 6, 8538.

[0206] Comparative Example 5

[0207] A DASA compound,

[0208]

[0209] Based on existing technology: Ester matters? Promoting photoisomerization of donor-acceptor Stenhouse adducts in the solid state and “burn after reading” encryption, Chem. Eng. J. 2022, 450, 138090. Preparation.

[0210] Comparative Example 6

[0211] A DASA compound,

[0212]

[0213] Based on existing technology: Tunable photothermal actuation enabled by photoswitching of donor-acceptor Stenhouse adducts, ACS Appl. Mater. Interfaces 2020, 12, 54075.

[0214] Result detection

[0215] The light fading and thermal recovery rates of the DASA compounds in this embodiment of the invention were detected in solution and in a polymer matrix. The specific detection methods are as follows:

[0216] The photofading rate of DASA compounds in solution was detected using a compound concentration of 10. -5 The chloroform solution of M was tested under xenon lamp irradiation at the corresponding absorption wavelength (wavelength and corresponding optical power density 550nm: 60.31mW / cm²). 2 600nm: 35.21mW / cm 2 620nm: 78.11mW / cm 2 635nm: 85.72mW / cm 2 ;) The time it takes for the absorbance of the maximum absorption peak to drop to its minimum value; the thermal recovery rate is calculated using a compound concentration of 10. -5 The time it takes for the absorbance of a chloroform solution of M to recover to its maximum value in a hot airflow at 60°C; the instrument used for detection was a QE Pro fiber optic spectrometer manufactured by Ocean Optics.

[0217] The photofading and thermal recovery rates of DASA compounds in a polymer matrix were measured using a 4% (w / w) polyurethane C85A film (BASF). Tests were conducted under xenon lamp irradiation at the corresponding absorption wavelength (wavelength and corresponding optical power density 550 nm: 60.31 mW / cm²).2 600nm: 35.21mW / cm 2 620nm: 78.11mW / cm 2 635nm: 85.72mW / cm 2 ;) The time it takes for the absorbance of the maximum absorption peak to drop to its lowest value; The thermal recovery rate is the time it takes for the absorbance of a polymer film with a compound mass fraction of 4% (including but not limited to thermoplastic polyurethane, polycaprolactone, polymethyl methacrylate, polystyrene, SBS, SEBS, etc.) to recover to its maximum value in a hot airflow at 60°C; The detection instrument is a QE Pro fiber optic spectrometer manufactured by Ocean Optics.

[0218] The fatigue resistance of the DASA compounds in this embodiment of the invention was tested, and the specific testing method is as follows:

[0219] The fatigue resistance of DASA compounds in polymer matrices was tested using polymer films containing 4% (by mass) of the compound (including but not limited to thermoplastic polyurethane, polycaprolactone, polymethyl methacrylate, polystyrene, SBS, SEBS, etc.). The tests were conducted under xenon lamp irradiation at the corresponding absorption wavelength (wavelength and corresponding optical power density 550nm: 60.31mW / cm²). 2 600nm: 35.21mW / cm 2 620nm: 78.11mW / cm 2 635nm: 85.72mW / cm 2 The number of cycles between the maximum absorption peak absorbance dropping to its lowest value and the maximum absorption peak absorbance recovering to its maximum value in a 60℃ hot airflow, and the percentage of absorbance retention, were measured using a QE Pro fiber optic spectrometer manufactured by Ocean Optics.

[0220] The specific test results are shown in Table 1 below.

[0221] Table 1. Light fading and thermal recovery rates (expressed as time to complete conversion, in seconds)

[0222]

[0223] As can be seen from Table 1 above, the nonlinear DASA compound of the present invention exhibits superior photochromic properties, with faster photochromic and thermal recovery rates. The nonlinear DASA compound of the present invention shows a photochromic rate of approximately 10 s in solution, with a maximum of 0.63 s, and a thermal recovery rate ranging from 0.9 to 81.4 s. Simultaneously, the linear DASA compound of the present invention also exhibits relatively fast photofading and thermal recovery rates in a polymer matrix.

[0224] The DASA compounds in other embodiments of the present invention also have substantially the same light fading rate and thermal recovery rate as in Example 1.

[0225] The fatigue resistance test results of the DASA compound in the polymer matrix show that the DASA compound of Example 1 of the present invention retains 97% absorbance after 200 cycles, 87% absorbance after 400 cycles, and 67% absorbance after 500 cycles, indicating good fatigue resistance in the polymer matrix.

[0226] Other DASA compounds of the present invention also exhibit fatigue resistance in polymer matrices comparable to those of Example 1.

[0227] In contrast, the DASA compound in Comparative Example 2 retained only 40% absorbance after 5 cycles.

[0228] In contrast, the DASA compound in Comparative Example 3 retained only 70% of its absorbance after 5 cycles.

[0229] In contrast, the DASA compound in Comparative Example 4 retained only 95% of its absorbance after 5 cycles.

[0230] In contrast, the DASA compound in Comparative Example 5 retained only 95% of its absorbance after 20 cycles.

[0231] In contrast, the DASA compound in Comparative Example 6 retained only 90% of its absorbance after 30 cycles.

[0232] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A DASA compound characterized in that, The structural formula is: wherein n = 1, R1is methyl or ethyl, is any one of the following: wherein m = 1, R1is methyl, is any one of:

2. The DASA compound of claim 1, wherein, Any one of the following structural formulae:

3. The DASA compound of claim 1, wherein Any one of the following structural formulae:

4. A process for the preparation of a DASA compound according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: The donor molecule and the acceptor molecule are mixed and dissolved in a dichloromethane / hexafluoroisopropanol mixed solvent, and a DASA compound is obtained by avoiding light reaction and purification, The molar ratio of the donor molecule to the acceptor molecule is ≤1:

3.

5. The preparation method according to claim 4, characterized in that, The donor molecule is: n=1, and R is methyl or ethyl; or wherein n = 1 and R is methyl; or wherein m = 1 and R is methyl.

6. The preparation method according to claim 4, characterized in that, The acceptor molecule is: any of the foregoing.

7. The preparation method according to claim 4, characterized in that, The molar ratio of the donor molecule to the acceptor molecule is 1:3-10.

8. The preparation method according to claim 4, characterized in that, The volume ratio of the dichloromethane to the hexafluoroisopropanol is 1-9:

1.

9. Use of the DASA compound in any one of claims 1-3 in the preparation of a photochromic dye.

10. A photochromic dye characterized in that, The method comprises the DASA compound in any one of claims 1-3.

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