Rhodamine force-induced color-changing luminescent material as well as preparation method and application thereof

Abstract

The invention belongs to the field of intelligent high polymer materials, and provides a rhodamine force-induced color-changing luminescent material as well as a preparation method and application thereof. The molecular formula of the rhodamine mechanochromic luminescent material is any one of the following # imgabs0 #, and the rhodamine mechanochromic luminescent material has the characteristics of various evolution forms, various luminescent colors and strong sensitivity control on external force response, and the mechanochromic high polymer material prepared from the rhodamine mechanochromic luminescent material has strong processing adaptability, and can adopt the current mature commercial processing preparation means. In addition, according to the preparation method of the rhodamine force-induced color-changing luminescent material, a commercialized polymer material can be adopted as a matrix, the processing and preparation process is simple, practicability is high, and large-scale preparation can be achieved.

Description

Technical Field

[0001] The invention relates to a rhodamine mechanochromic luminescent material, a preparation method and application thereof, and belongs to the field of intelligent polymer materials. Background Art

[0002] When mechanochromic luminescent materials are subjected to external forces (such as stretching, compression, impact, static pressure, etc.), their fluorescence color and luminescence intensity change significantly. Such materials are of great application value in medical stress sensing, crack warning, strain detection, trademark anti-counterfeiting, optoelectronic storage, display devices, etc. Mechanochromic luminescent materials can be realized by doping with color-changing small molecule aggregates or introducing chemical structures that can induce structural changes in polymer networks. The method of doping with small molecule aggregates has a complex preparation process and high material requirements for the preparation of mechanochromic luminescent materials. The mechanochromic luminescent materials prepared by introducing functional molecules have the characteristics of simple preparation, wide range of applications, and low requirements for polymer matrices. In the past two decades, a series of mechanochromic luminescent functional molecules, such as spiropyran, rhodamine 6G, dioxocyclobutane, etc., have been used to prepare mechanochromic luminescent materials.

[0003] Rhodamine is a widely used fluorescent probe with advantages such as good stability, high fluorescence quantum yield and high sensitivity. However, the rhodamine mechanochromic luminescent materials reported so far are few in variety, have single luminescent color, and are difficult to control in terms of sensitivity to external forces. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a rhodamine mechanochromic luminescent material, a preparation method and its application, which solves the problems in the prior art that the rhodamine mechanochromic luminescent materials are few in variety, single in luminescent color, difficult to control sensitivity to external force, difficult in processing technology and difficult in forming.

[0005] The present invention provides a rhodamine mechanochromic luminescent material, the chemical structural formula of which is any one of the following:

[0006]

[0007] In formula (1), Z is H or methyl;

[0008] Ar is a structure having an aromatic skeleton, and the structural formula having an aromatic skeleton is any one of the following:

[0009]

[0010] The Y1 is a substituent I, and Y2 is a substituent II. The chemical structural formulas of the substituent I and the substituent II are any of the following:

[0011]

[0012]

[0013] Wherein, each of substituents I and II contains a polymerization site group, which is any one of R1 to R7; other R1 to R7 except the polymerization site group are independently H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; ● represents the position connected to N in formula (1);

[0014] The polymerization site group is a substituent group III, and the chemical structure of the substituent group III is any one of the following:

[0015]

[0016] Wherein, W represents -C(O)O-, -OC(O)-, -C(O)NH- or -NHC(O)-; R8 is H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; R represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or a bond; ● represents the position of connection to substituent I or substituent II.

[0017] The present invention also provides a mechanochromic polymer material, which is obtained by introducing the rhodamine mechanochromic luminescent material into a polymer skeleton through covalent bonding.

[0018] Preferably, the mechanochromic polymer material, the polymer is a polymer elastomer, including polymethyl acrylate elastomer, polysiloxane elastomer, polymethacrylate glassy polymer, multi-network polymer, polyurethane polymer, polyurea polymer, polyolefin polymer, polyamide polymer, phenolic resin, epoxy resin, amino resin or polyacrylonitrile.

[0019] The present invention also provides a method for preparing a rhodamine mechanochromic luminescent material, comprising the following steps:

[0020] Step 1: 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid or 2-(4-(ethylamino)-2-hydroxybenzoyl)benzoic acid, phenol or a phenol derivative in which the ortho position of the phenolic hydroxyl group is H, and methanesulfonic acid are mixed to obtain a reaction system, and the system is subjected to heating reaction, pH neutralization, filtration, and purification to obtain compound 1;

[0021] Step 2: Compound 1, Y2-substituted ammonia and ethanol are mixed to obtain a reaction system, and the mixture is subjected to heating reflux reaction, rotary evaporation, extraction and purification to obtain compound 2;

[0022] Step 3: Compound 2, Y1-substituted halide and potassium carbonate are mixed to obtain a reaction system, and compound 3 is obtained by heating, reacting, filtering, extracting and purifying;

[0023] Wherein, Y1 is substituent I, Y2 is substituent II, and the chemical structural formulas of substituent I and substituent II are any of the following:

[0024]

[0025]

[0026] Wherein, each of substituents I and II contains a polymerization site group, which is any one of R1 to R7; other R1 to R7 except the polymerization site group are independently H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; ● represents the position connected to N in formula (1);

[0027] The polymerization site group is a substituent group III, and the chemical structure of the substituent group III is any one of the following:

[0028]

[0029] Wherein, W represents -C(O)O-, -OC(O)-, -C(O)NH- or -NHC(O)-; R8 is H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; R represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or a bond; ● represents the position of connection to substituent I or substituent II.

[0030] Preferably, the phenol derivative in which the ortho position of the phenolic hydroxyl group is H is one of the following:

[0031]

[0032] Preferably, in step 1: the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid or 2-(4-(ethylamino)-2-hydroxybenzoyl)benzoic acid, phenol or a phenol derivative having H at the ortho position of the phenolic hydroxyl group, and methanesulfonic acid is 1 mol: 1-2 mol: 30-40 mol; the heating reaction temperature is 80-100° C.; the heating reaction time is 12-24 h; the purification is column chromatography purification, and the column chromatography purification eluents are dichloromethane and methanol; the volume ratio of dichloromethane: methanol is 20-40:1.

[0033] Preferably, in step 2:

[0034] The molar ratio of compound 1 and Y2-substituted ammonia and ethanol is 1 mol: 2-20 mol: 50-900 mol; the temperature of the heating reflux reaction is 80-100°C; the heating reflux reaction time is 24-48 hours; the purification is column chromatography purification, and the column chromatography purification eluent is petroleum ether and ethyl acetate or dichloromethane and methanol; the volume ratio of petroleum ether and ethyl acetate is 1-4:1; the volume ratio of dichloromethane: methanol is 30-40:1.

[0035] Preferably, in step 3: the halogen atom in the Y1-substituted halide is I or Br; the molar ratio of compound 2, Y1-substituted halide and potassium carbonate is 1 mol:20-40 mol:8-16 mol; the heating reaction temperature is 80-100°C; the heating reaction time is 4-8h; the purification is column chromatography purification, and the column chromatography purification eluent is petroleum ether and ethyl acetate or dichloromethane and methanol; the volume ratio of petroleum ether:ethyl acetate is 0.5-4:1; the volume ratio of dichloromethane:methanol is 20-40:1.

[0036] Preferably, the preparation method further comprises step 4: modifying compound 3 by changing Y1 and / or Y2 to meet application requirements.

[0037] The present invention also provides an application of the rhodamine mechanochromic luminescent material, characterized in that it is used in mechanochromic luminescent hydrogels, mechanochromic luminescent elastomers, thermoplastic mechanochromic luminescent polyurethanes, probes, stress detection, failure analysis, intelligent display and damage warning.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) The rhodamine mechanochromic luminescent material of the present invention has various evolution forms, various luminescent colors, and strong control over the sensitivity of the response to external force.

[0040] (2) The preparation method of the present invention can use commercialized polymer materials as the matrix, has a simple processing and preparation process, is highly practical, and can be prepared on a large scale.

[0041] (3) The preparation method of the present invention can prepare mechanochromic polymer materials of different shapes (such as blocks, films, fibers, etc.), has strong processing adaptability, and can adopt currently mature commercial processing and preparation methods, including extrusion molding, compression molding, additive manufacturing, etc.

[0042] (4) The rhodamine mechanochromic luminescent material of the present invention has the property of changing color in response to mechanical force. By adding it as a functional monomer into a polymerization reaction, a mechanochromic luminescent polymer material can be prepared. The luminescent color changes rapidly and reversibly due to stretching or compression, and the stress applied to the material can be visualized in real time.

[0043] (5) The rhodamine mechanochromic luminescent material of the present invention is a bifunctional rhodamine molecule, which is added as a functional monomer to the main chain position of a thermoplastic polymer. The obtained thermoplastic mechanochromic luminescent polymer material is easy to process, has strong plasticity and is recyclable.

[0044] (6) The rhodamine mechanochromic luminescent material of the present invention contains bifunctional mechanochromic luminescent rhodamine molecules with different substituents, which are added as cross-linking agents to the cross-linking points of thermosetting polymers to prepare mechanochromic luminescent polymer materials with good stability and adjustable mechanical properties, thereby meeting diverse application scenarios.

[0045] (7) The mechanochromic luminescent rhodamine molecules of the rhodamine mechanochromic luminescent material of the present invention not only do not significantly change the mechanical properties of the mechanochromic luminescent polymer material, but also significantly change the mechanochromic luminescent properties.

[0046] (8) The mechanochromic luminescent polymer material of the present invention has good sensitivity to force response, mechanochromic luminescent color, and recovery properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 1 is the fluorescence emission spectrum of the mechanochromic luminescent elastomer prepared in Example 1 of the present invention at different stretching ratios.

[0049] Figure 2 1 is the fluorescence emission spectrum of the mechanochromic luminescent elastomer prepared in Example 1 of the present invention under different states.

[0050] Figure 3 1 is the fluorescence emission spectrum of the mechanochromic luminescent elastomer prepared in Example 2 of the present invention at different stretching ratios.

[0051] Figure 4 Graphs showing the fluorescence emission spectra of the mechanochromic luminescent elastomer prepared in Example 3 of the present invention at different stretching ratios.

[0052] Figure 5 4 is the fluorescence emission spectrum of the mechanochromic luminescent elastomer prepared in Example 4 of the present invention at different stretching ratios.

[0053] Figure 6 1 is the fluorescence emission spectrum of the mechanochromic luminescent elastomer prepared in Example 5 of the present invention at different stretching ratios.

[0054] Figure 7 Graphs showing the fluorescence emission spectra of the mechanochromic luminescent hydrogel prepared in Example 6 of the present invention at different stretching ratios.

[0055] Figure 8 1 is the fluorescence emission spectrum of the mechanochromic luminescent thermoplastic polyurethane prepared in Example 7 of the present invention under different states.

[0056] Fig. 9 It is the chemical structural formula of the rhodamine mechanochromic luminescent material of the present invention. DETAILED DESCRIPTION

[0057] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art will appreciate that the implementation cases described below are part of the implementation cases, do not include all the implementation cases, are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the implementation cases in the present invention, all other implementation cases obtained by ordinary technicians of the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not specified in the implementation cases, proceed according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0058] In one aspect of the present invention, a rhodamine mechanochromic luminescent material is provided, wherein the chemical structural formula of the material is any one of the following:

[0059]

[0060] Furthermore, in formula (1), Z is H or methyl; Ar is a structure having an aromatic skeleton;

[0061] Preferably, the structural formula having an aromatic skeleton is any one of the following:

[0062]

[0063] Furthermore, Y1 is a substituent I, and Y2 is a substituent II.

[0064] Preferably, the chemical structural formula of substituent I and substituent II is any one of the following:

[0065]

[0066]

[0067] Wherein, substituent I and substituent II each contain a polymerization site group, which is any one of R1 to R7; other R1 to R7 except the polymerization site group are each independently H, a straight-chain, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; ● represents the position connected to N in formula (1).

[0068] Furthermore, the polymerization site group is substituent III.

[0069] Preferably, the chemical structural formula of the substituent group II is any one of the following:

[0070]

[0071]

[0072] Wherein, W represents -C(O)O-, -OC(O)-, -C(O)NH- or -NHC(O)-; R8 is H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; R represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or a bond; ● represents the position of connection to substituent I or substituent II.

[0073] The luminescent color of the mechanochromic polymer material obtained by covalently linking the rhodamine mechanochromic luminescent material to the polymer chain of the present invention changes rapidly with external force (stretching, compression, shearing, impact, etc.), so the stress state inside the material can be visualized in real time.

[0074] Furthermore, the rhodamine mechanochromic luminescent material of formula (1) is introduced into the polymer backbone by covalent bonding to obtain a mechanochromic polymer material.

[0075] Furthermore, the polymer skeleton is a polymer elastomer; the polymer elastomer includes but is not limited to polymethyl acrylate elastomers, polysiloxane elastomers, polymethacrylate glassy polymers, multi-network polymers, polyurethane polymers, polyurea polymers, polyolefin polymers, polyamide polymers, phenolic resins, epoxy resins, amino resins or polyacrylonitrile.

[0076] Exemplarily, when the aforementioned polymer elastomer is a polyacrylate elastomer, the monomers in the polymer precursor for preparing the polyacrylate elastomer are acrylates with different substituents (such as methyl acrylate, ethyl acrylate, butyl methacrylate, hexafluorobutyl methacrylate and methyl methacrylate, etc.); the cross-linking agent is 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate and ethylene glycol dimethacrylate, etc.; the initiator is a thermal initiator (such as benzoyl peroxide and azobisisobutyronitrile, etc.) or a photoinitiator (such as 2-hydroxy-2-methyl-1-phenylpropanone and 1-hydroxycyclohexyl phenyl ketone, etc.).

[0077] For another example, when the polymer elastomer is a polyacrylamide elastomer, the monomers in the polymer precursor for preparing the polyacrylic acid ester elastomer are acrylamides with different substituents (such as acrylamide, N-methylacrylamide, N-ethylmethylacrylamide and N-phenylmethylacrylamide, etc.) or 2-acrylamide-2-methylpropane sulfonic acid; the cross-linking agent is N,N'-methylenebisacrylamide, 1,6-hexanediol diacrylate and ethylene glycol dimethacrylate, etc.; the initiator is a thermal initiator (such as benzoyl peroxide, azobisisobutyronitrile and ammonium persulfate, etc.) or a photoinitiator (such as 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and 1-hydroxycyclohexyl phenyl ketone, etc.).

[0078] Another aspect of the present invention provides a method for preparing a rhodamine mechanochromic luminescent material, and the preparation reaction formula is as follows:

[0079]

[0080] The preparation method comprises the following steps:

[0081] Step 1: Mix 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid or 2-(4-(ethylamino)-2-hydroxybenzoyl)benzoic acid, phenol or a phenol derivative in which the ortho-position of the phenolic hydroxyl group is H, and methanesulfonic acid to obtain a reaction system, heat the reaction, neutralize the system after the reaction with sodium carbonate solution, filter to remove the liquid, and purify to obtain compound 1.

[0082] Preferably, the phenol derivative with H at the ortho position of the phenolic hydroxyl group is one of the following:

[0083]

[0084] Furthermore, the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid or 2-(4-(ethylamino)-2-hydroxybenzoyl)benzoic acid, phenol or a phenol derivative with H at the ortho position of the phenolic hydroxyl group, and methanesulfonic acid is 1 mol: 1-2 mol: 30-40 mol; the heating reaction temperature is 80-100°C; the heating reaction time is 12-24h; the purification is column chromatography purification, and the column chromatography purification eluents are dichloromethane and methanol; the volume ratio of dichloromethane: methanol is 20-40:1.

[0085] Step 2: Compound 1, Y2-substituted ammonia and ethanol are mixed to obtain a reaction system, and the mixture is heated to reflux for reaction. The ethanol is removed by rotary evaporation from the system after the reaction, and unreacted raw materials are removed by extraction, and compound 2 is obtained by purification.

[0086] Furthermore, the molar ratio of compound 1 and Y2 replacing ammonia and ethanol is 1 mol: 2-20 mol: 50-900 mol; the temperature of the heating reflux reaction is 80-100°C; the heating reflux reaction time is 24-48h; the purification is column chromatography purification, and the column chromatography purification eluent is petroleum ether and ethyl acetate or dichloromethane and methanol; the volume ratio of petroleum ether and ethyl acetate is 1-4:1; the volume ratio of dichloromethane: methanol is 30-40:1.

[0087] Step 3: Compound 2, Y1-substituted halide and potassium carbonate are mixed to obtain a reaction system, and the mixture is heated to react. The system after the reaction is completed is filtered to remove the solid, and the liquid is removed by extraction, and then purified to obtain compound 3.

[0088] Preferably, the halogen atom in the Y1-substituted halide is I or Br.

[0089] Furthermore, the molar ratio of compound 2, Y1-substituted halide and potassium carbonate is 1 mol: 20-40 mol: 8-16 mol. The heating reaction temperature is 80-100° C. and the heating reaction time is 4-8 hours.

[0090] Furthermore, the purification is column chromatography purification, and the column chromatography purification eluent is petroleum ether and ethyl acetate or dichloromethane and methanol; the volume ratio of petroleum ether:ethyl acetate is 0.5-4:1; the volume ratio of dichloromethane:methanol is 20-40:1.

[0091] Step 4: Modify compound 3 by changing Y1 and / or Y2 to meet application requirements.

[0092] The third aspect of the present invention provides an application of rhodamine mechanochromic luminescent material, which is used in mechanochromic luminescent hydrogels, mechanochromic luminescent elastomers, thermoplastic mechanochromic luminescent polyurethanes, probes, stress detection, failure analysis, intelligent display and damage warning.

[0093] In order to illustrate the effectiveness of the method proposed in the present invention, the above technical solution of the present invention is described in detail below through specific embodiments, and the specific implementation steps are as follows:

[0094] Example 1

[0095] A rhodamine derivative Rh-NEt2 having a mechanochromic effect, wherein the chemical structure of the molecule is as follows (2):

[0096]

[0097] The preparation reaction formula of the above-mentioned rhodamine derivative Rh-NEt2 having a mechanochromic effect is as follows:

[0098]

[0099] The preparation method of the above-mentioned rhodamine derivative Rh-NEt2 having a mechanochromic effect is as follows:

[0100] Step 1, 4.00 g (13.36 mmol) of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid and 4.42 g (26.73 mmol) of 3-diethylaminophenol were reacted in 30 mL of methanesulfonic acid at 90° C. for 24 hours; after the reaction, the mixture was neutralized with a saturated sodium carbonate solution, the filter cake was filtered out, and the mixture was purified by silica gel column chromatography using dichloromethane / methanol in a volume ratio of 30 / 1 as the eluent to obtain an orange solid 1a with a yield of 42%.

[0101] Specifically, the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid, 3-diethylaminophenol, and methanesulfonic acid is 1:2:34.60.

[0102] The NMR spectrum data of orange solid 1a are as follows:

[0103] 1 H NMR (600MHz, Methanol-d4) δ8.21-8.01(m,1H),7.63(dtd,J=17.8,7.4,1.5Hz,2H),7.34-7.18(m,2H),7.04(d,J=1.1Hz,1H),6.99(dd,J=9.5,2 .5Hz,1H),6.91(d,J=2.5Hz,1H),6.83(s,1H),3.63(p,J=7.4Hz,4H),3.49(q,J=7.2Hz,2H),2.10(d,J=1.1Hz,3H),1.31(dt,J=22.6,7.1Hz,9H).

[0104] Step 2, 2.0 g (4.67 mmol) of compound 1a and 4.43 g (72.53 mmol) of ethanolamine were refluxed in 30 mL of ethanol at 90° C. for 48 hours; after the reaction, ethanol was removed by rotary evaporation, the crude product was dissolved in chloroform, extracted with saturated brine, the organic phase was collected, dried by rotary evaporation, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 3 / 1 as the eluent to obtain a white compound 2a with a yield of 58%.

[0105] Specifically, the molar ratio of compound 2a, ethanolamine, and ethanol is 1:15.53:110.

[0106] The NMR spectrum data of white compound 2a are as follows:

[0107] 1 H NMR(600MHz,DMSO-d6)δ7.79-7.73(m,1H),7.53-7.45(m,2H),7.01-6.95(m,1H),6.38-6.24(m,4H),6.10(s,1H),3.31 (q,J=7.3Hz,4H),3.13(q,J=7.1Hz,2H),3.05-2.92(m,4H),1.86(s,3H),1.21(t,J=7.1Hz,3H),1.08(t,J=7.0Hz,6H).

[0108] Step 3, 1.50 g (3.18 mmol) of compound 2a and 3.52 g (25.45 mmol) of potassium carbonate were reacted in 19.14 g (111.30 mmol) of iodoethanol at 90° C. for 6 hours. After the reaction was completed, the filtrate was filtered and extracted with dichloromethane and water, the organic phase was collected and dried, and the eluent was dichloromethane / methanol in a volume ratio of 20 / 1 to perform silica gel column chromatography purification to obtain a light yellow compound 3a with a yield of 70%.

[0109] Specifically, the molar ratio of compound 3a, potassium carbonate and iodoethanol is 1:8:35.

[0110] The NMR spectrum data of compound 3a are shown below:

[0111] 1H NMR (600MHz, CDCl3) δ7.95-7.90(m,1H),7.52-7.45(m,2H),7.08-7.02(m,1H),6.91(s,1H),6.53-6.45(m,2H),6.38-6.28(m,2H),3.6 5-3.56(m,2H),3.51-3.42(m,2H),3.38-3.16(m,8H),3.02(p,J=7.0Hz,2H),2.09(s,3H),1.17(t,J=7.1Hz,6H),1.03(t,J=7.0Hz,3H).

[0112] Step 4, 1.40 g (2.25 mmol) of compound 3a and 2.05 g (20.25 mmol) of triethylamine were dissolved in 30 mL of tetrahydrofuran and cooled to -10°C, and then 1.22 g (13.50 mmol) of acryloyl chloride was slowly added dropwise to the mixture, and the reaction system was stirred at room temperature for 12 h; after the reaction was completed, impurities were removed by suction filtration, and excess tetrahydrofuran was removed by rotary evaporation, and petroleum ether / ethyl acetate in a volume ratio of 3 / 1 was used as the eluent for purification by silica gel column chromatography to obtain light yellow oily liquid Rh-NEt2 with a yield of 81%.

[0113] Specifically, the molar ratio of compound 3a, triethylamine, acryloyl chloride and tetrahydrofuran is 1:9:6:164.

[0114] The NMR spectrum data of the light yellow oily liquid Rh-NEt2 is as follows:

[0115] 1 H NMR(600MHz,DMSO-d6)δ7.89-7.75(m,1H),7.60-7.46(m,2H),7.06-7.00 (m,1H),6.96(s,1H),6.43-6.00(m,7H),5.95-5.78(m,3H),4.16(t,J=5.9 Hz,2H),3.83-3.62(m,2H),3.43-3.33(m,2H),3.32-3.21(m,5H),3.04(q ,J=7.0Hz,2H),1.95(s,3H),1.08(t,J=7.0Hz,6H),0.96(t,J=7.0Hz,3H).

[0116] The rhodamine mechanochromic luminescent molecule is used to prepare the mechanochromic luminescent elastomer, and the specific steps are as follows:

[0117] First, 0.06g Rh-NEt2 and 0.006g I2959 synthesized above were dissolved in 1.2mL of ethyl acrylate, and the first layer of network was obtained after 5min of 365nm UV curing in the mold. The network was immersed in a solution containing 0.54g I2959, 79.8μL 1,4-butanediol diacrylate and 81mL methyl acrylate for 20min, taken out, and UV-cured for 5min to obtain a double network elastomer. The network was immersed in a solution containing 0.54g I2959, 79.8μL 1,4-butanediol diacrylate and 81mL methyl acrylate for 40min, taken out, and UV-cured for 5min to obtain a mechanochromic luminescent elastomer film.

[0118] The film was clamped on a mold and the changes in fluorescence color and intensity during stretching and relaxation were observed under 365 nm ultraviolet light. Figure 1 The fluorescence emission spectra at different stretching ratios are shown in Figure 4. The 430nm peak is selected as the normalized peak. It can be found that under external force stimulation, as the stretching ratio increases, the fluorescence emission peak at around 628nm gradually increases, and the originally light blue elastic film gradually shows orange-red fluorescence. After rapid relaxation, Figure 2 The fluorescence emission wavelength of the elastomer film is shown to be blue-shifted from 628 nm to 588 nm, which may be due to the change in the conformation of the rhodamine chromophore. This proves that the mechanochromic luminescent elastomer prepared in Example 1 exhibits the property of mechanochromic luminescence.

[0119] Example 2

[0120] A rhodamine derivative Rh-OMe with a mechanochromic effect, the chemical structure of the molecule is as follows (3):

[0121]

[0122] The preparation reaction formula of the rhodamine derivative Rh-OMe with the above-mentioned mechanochromic effect is as follows:

[0123]

[0124] The preparation method of the rhodamine derivative Rh-OMe with the above-mentioned mechanochromic effect is as follows:

[0125] Step 1, 4.00 g (13.36 mol) of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid and 3.32 g (26.73 mmol) of 3-methoxyphenol were reacted in 30 mL of methanesulfonic acid at 90° C. for 24 hours; after the reaction, the mixture was neutralized with a saturated sodium carbonate solution, the filter cake was filtered out, and the mixture was purified by silica gel column chromatography using dichloromethane / methanol in a volume ratio of 40 / 1 as the eluent to obtain a brown compound 1b with a yield of 48%.

[0126] Specifically, the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid, 3-methoxyphenol, and methanesulfonic acid is 1:2:34.6.

[0127] The NMR spectrum data of brown compound 1b are as follows:

[0128] 1 H NMR(600MHz,DMSO-d6)δ7.99(dt,1H),7.80-7.67(m,2H),7.22(dt,1H),6.87(d,1H),6.67(dd,1H),6.6 0(d,1H),6.36(s,1H),6.28(d,1H),5.75(s,1H),3.80(d,3H),3.17(dd,2H),1.91(d,3H),1.21(t,3H).

[0129] Step 2, 2.00 g (5.16 mmol) of compound 1b and 4.90 g (80.22 mmol) of ethanolamine were refluxed in 30 mL of ethanol at 90° C. for 48 hours; after the reaction, ethanol was removed by rotary evaporation, the crude product was dissolved with chloroform, extracted with saturated brine, the organic phase was collected, dried by rotary evaporation, and purified by silica gel column chromatography using dichloromethane / methanol in a volume ratio of 30 / 1 as the eluent to obtain a white solid compound 2b with a yield of 50%.

[0130] Specifically, the molar ratio of compound 1b, ethanolamine, and ethanol is 1:15.54:100.

[0131] The NMR spectrum data of white solid compound 2b are as follows:

[0132] 1 H NMR(600MHz,DMSO-d6)δ7.87-7.72(m,1H),7.57-7.43(m,2H),7.07-6.91(m,1H),6.79(d,1H),6.59(dd,1H),6.45(d,1H),6.30(s,1H ),6.12(d,1H),5.75(s,1H),5.16(t,1H),4.54(t,1H),3.77(s,3H),3.14(m,2H),3.09-2.87(m,4H),1.98-1.82(m,3H),1.21(t,3H).

[0133] Step 3, 1.61 g (3.75 mmol) of compound 2b and 4.14 g (29.96 mmol) of potassium carbonate were reacted in 22.57 g (131.25 mmol) of iodoethanol at 90° C. for 6 hours; after the reaction, the filtrate was filtered and extracted with dichloromethane and water, the organic phase was taken, spin-dried, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 2:1 as the eluent to obtain a yellow solid compound 3b with a yield of 72%.

[0134] Specifically, the molar ratio of compound 2b, potassium carbonate and iodoethanol is 1:8:35.

[0135] The NMR spectrum data of yellow solid compound 3b are as follows:

[0136] 1 H NMR(600MHz,DMSO-d6)δ7.91-7.76(m,1H),7.59-7.46(m,2H),7.09-6.90(m,2H),6.82(d,1H),6.62(dd ,1H),6.49(d,1H),6.35(s,1H),3.78(s,3H),3.44(t,2H),3.11-2.91(m,8H),2.02(s,3H),0.96(t,3H).

[0137] Step 4, 1.05 g (2.25 mmol) of compound 3b and 2.05 g (20.25 mmol) of triethylamine were dissolved in 30 mL of tetrahydrofuran and cooled to -10°C, and then acryloyl chloride (1.22 g, 13.50 mmol) was slowly added dropwise to the mixture, and the reaction system was stirred at room temperature for 12 h; after the reaction was completed, impurities were removed by suction filtration, and excess tetrahydrofuran was removed by rotary evaporation, and silica gel column chromatography was performed with a volume ratio of petroleum ether / ethyl acetate = 3 / 1 as the eluent to obtain light yellow oily liquid Rh-OMe. The yield was 80%.

[0138] Specifically, the molar ratio of compound 3b, acryloyl chloride, triethylamine and tetrahydrofuran is 1:9:6:164.

[0139] The NMR spectrum data of light yellow oily liquid Rh-OMe are as follows:

[0140] 1H NMR(600MHz,DMSO-d6)δ7.93-7.76(m,1H),7.62-7.47(m,2H),7.11-6.93(m,2H),6.82(d,1H),6.62(dd,1H),6.50(d,1H),6.37(s,1H),6.29-5.98 (m,3H),5.98-5.79(m,3H),4.17(t,2H),3.79(s,3H),3.77-3.65(m,2H), 3.42-3.36(m,1H),3.28(dt,3H),3.06(q,2H),1.97(s,4H),0.97(t,3H).

[0141] The mechanochromic luminescent elastomer of this embodiment is prepared by the same method as that of the mechanochromic luminescent elastomer in Embodiment 1, except that 0.056 g of Rh-OMe is used instead of 0.06 g of Rh-NEt2. Figure 3 The normalized fluorescence emission spectra of the mechanochromic luminescent elastomer film of this embodiment at different stretching ratios are shown in Figure 4, with 430 nm selected as the normalized peak. It can be found that under external force stimulation, as the stretching ratio increases, the fluorescence emission peak intensity at 567 nm gradually increases, thereby proving that the mechanochromic luminescent elastomer prepared in Example 2 exhibits the property of mechanochromic luminescence.

[0142] Example 3

[0143] A rhodamine derivative Rh-H with a mechanochromic effect, the chemical structure of the molecule is as follows (4):

[0144]

[0145] The preparation reaction formula of the above-mentioned rhodamine derivative Rh-H with mechanochromic effect is as follows:

[0146]

[0147] The preparation method of the rhodamine derivative Rh-H with the above-mentioned mechanochromic effect is as follows:

[0148] Step 1, react 4.00 g (13.36 mmol) of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid and 2.00 g (26.73 mmol) of phenol in 30 mL of methanesulfonic acid at 90° C. for 12 hours; after the reaction, neutralize with saturated sodium carbonate solution, filter and obtain the filter cake, and purify by silica gel column chromatography using dichloromethane / methanol in a volume ratio of 40:1 as the eluent to obtain a light yellow compound 1c with a yield of 41%.

[0149] Specifically, the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid, phenol, and methanesulfonic acid is 1:2:34.6.

[0150] The NMR spectrum data of the light yellow compound 1c are as follows:

[0151] 1 H NMR(600MHz, CDCl3)δ8.13-7.96(m,1H),7.75-7.53(m,2H),7.37(s,0H),7.31-7. 10(m,2H),7.05-6.73(m,1H),6.44(d,2H),3.25(d,2H),1.96(s,3H),1.33(t,4H).

[0152] Step 2, 2.00 g (5.60 mmol) of compound 1c and 5.31 g (86.96 mmol) of ethanolamine were refluxed in 30 mL of ethanol at 90° C. for 48 hours; after the reaction, ethanol was removed by rotary evaporation, the crude product was dissolved with chloroform, extracted with saturated brine, the organic phase was collected, dried by rotary evaporation, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 2:1 as the eluent to obtain a white product compound 2c with a yield of 58%.

[0153] Specifically, the molar ratio of compound 1c, ethanolamine, and ethanol is 1:15.52:91.75.

[0154] The NMR spectrum data of white compound 2c are as follows:

[0155] 1 H NMR(600MHz,DMSO-d6)δ7.86-7.74(m,1H),7.57-7.46(m,2H),7.37-7.21(m,2H),7.04-6.92(m,2H),6.57(dd,1H) ,6.33(s,1H),6.15(d,1H),5.17(t,1H),4.54(t,1H),3.15(dd,2H),3.07-2.85(m,3H),1.89(s,3H),1.22(t,4H).

[0156] Step 3, 1.50 g (3.75 mmol) of compound 2c and 4.14 g (29.96 mmol) of potassium carbonate were reacted in 22.57 g (131.25 mmol) of iodoethanol at 90° C. for 6 hours; after the reaction, the filtrate was filtered and extracted with dichloromethane and water, the organic phase was taken and dried, and silica gel column chromatography was performed with dichloromethane / methanol in a volume ratio of 20:1 as the eluent to obtain a light yellow compound 3c with a yield of 70%.

[0157] Specifically, the molar ratio of compound 2a, potassium carbonate and iodoethanol is 1:8:35.

[0158] The NMR spectrum data of the light yellow compound 3c are as follows:

[0159] 1 H NMR(600MHz,DMSO-d6)δ7.84-7.80(m,1H),7.56-7.50(m,2H),7.40-7.35(m,1H),7.28(dd,1H),7.06-6.99(m,2H),6.97 (s,1H),6.61(dd,1H),6.37(s,1H),4.50(d,1H),3.43(d,2H),3.05(m,6H),2.99-2.88(m,2H),2.02(s,3H),0.96(t,3H).

[0160] Step 4, 1.00 g (2.25 mmol) of compound 3c and 2.05 g (20.25 mmol) of triethylamine were dissolved in 30 mL of tetrahydrofuran and cooled to -10°C, and then 1.22 g (13.50 mmol) of acryloyl chloride was slowly added dropwise to the mixture, and the reaction system was stirred at room temperature for 12 h; after the reaction was completed, impurities were removed by suction filtration, and excess tetrahydrofuran was removed by rotary evaporation, and petroleum ether / ethyl acetate volume ratio = 3 / 1 was used as eluent for purification by silica gel column chromatography to obtain light yellow oily liquid Rh-H with a yield of 80%.

[0161] Specifically, the molar ratio of compound 3c, triethylamine, acryloyl chloride and tetrahydrofuran is 1:9:6:164.

[0162] The NMR spectrum data of the light yellow oily liquid Rh-H is as follows:

[0163] 1 H NMR(600MHz,DMSO-d6)δ7.87-7.85(m,1H),7.56-7.52(m,2H),7.37(dd,1H),7.28(dd,1H),7.04-6.98(m,3H),6.61(dd,1H),6.39(s,1H),6.19(d d,2H),6.05(dd,1H),5.92-5.82(m,3H),4.17(t,2H),3.77-3.65(m,2H), 3.41(dd,1H),3.34-3.26(m,3H),3.04(q,2H),1.97(s,3H),0.96(t,3H).

[0164] The mechanochromic luminescent elastomer of this embodiment is prepared by the same method as that of the mechanochromic luminescent elastomer in Embodiment 1, except that 0.053 g Rh-H is used instead of 0.06 g Rh-NEt2. Figure 4 The normalized fluorescence emission spectra of the mechanochromic luminescent elastomer film of this embodiment at different stretching ratios are shown in Figure 4, with 430 nm selected as the normalized peak. It can be found that under external force stimulation, as the stretching ratio increases, the fluorescence emission peak intensity at 553 nm gradually increases, thereby proving that the mechanochromic luminescent elastomer prepared in Example 3 exhibits the property of mechanochromic luminescence.

[0165] Example 4

[0166] A rhodamine derivative Rh-Ph with a mechanochromic effect, the chemical structure of the material is as follows (5):

[0167]

[0168] The preparation reaction formula of the above-mentioned rhodamine derivative Rh-Ph with mechanochromic effect is as follows:

[0169]

[0170] The preparation method of the rhodamine derivative Rh-Ph with the above-mentioned mechanochromic effect is as follows:

[0171] Step 1, 4.00 g (13.36 mmol) of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid and 5.78 g (40.09 mmol) of naphthol were reacted in 30 mL of methanesulfonic acid at 90° C. for 24 hours; after the reaction, the mixture was neutralized with a saturated sodium carbonate solution, and the filter cake was filtered out and purified by silica gel column chromatography using dichloromethane / methanol in a volume ratio of 40 / 1 as the eluent to obtain a light yellow solid compound 1d with a yield of 38%.

[0172] Specifically, the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid, naphthol, and methanesulfonic acid is 1:3:34.60.

[0173] The NMR spectrum data of the light yellow solid compound 1d are as follows:

[0174] 1H NMR (600MHz, CDCl3) δ8.61(dd,1H),8.08(dt,1H),7.85-7.77(m,1H),7.67-7.58(m,5H),7.43(d,1H),7. 18-7.11(m,1H),6.79-6.73(m,1H),6.64(s,1H),6.50(dd,1H),3.32(dt,2H),2.00(s,3H),1.38(t,3H).

[0175] Step 2, 2.00 g (4.91 mmol) of compound 1d and 4.66 g (76.28 mmol) of ethanolamine were refluxed in 40 mL of ethanol at 90° C. for 48 hours; after the reaction, ethanol was removed by rotary evaporation, the crude product was dissolved with chloroform, extracted with saturated brine, the organic phase was collected, dried by rotary evaporation, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 1.5:1 as the eluent to obtain a light yellow solid compound 2d with a yield of 55%.

[0176] Specifically, the molar ratio of compound 1d, ethanolamine, and ethanol is 1:15.53:139.52.

[0177] The NMR spectrum data of the light yellow solid compound 2d are as follows:

[0178] 1 H NMR(600MHz,DMSO-d6)δ8.56-8.51(m,1H),7.92-7.83(m,2H),7.67(dd,2H),7.57-7.47(m,3H),7.04(dt,1 H),6.67-6.41(m,2H),6.20(d,1H),5.22(t,1H),4.48(t,1H),3.26-2.77(m,6H),1.92(d,3H),1.27(t,3H).

[0179] Step 3, 1.50 g (3.33 mmol) of compound 2d and 3.68 g (26.63 mmol) of potassium carbonate were reacted in 20.04 g (116.55 mmol) of iodoethanol at 90°C for 6 hours; after the reaction, the filtrate was filtered and extracted with dichloromethane and water, the organic phase was taken, spin-dried, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 2 / 1 as an eluent to obtain a yellow solid 3d with a yield of 58%. Specifically, the molar ratio of compound 3d, potassium carbonate, and iodoethanol is 1:8:35.

[0180] The NMR spectrum data of the yellow solid 2d is as follows:

[0181] 1H NMR(600MHz,DMSO-d6)δ8.64-8.46(m,1H),8.02-7.81(m,2H),7.70(dd,2H),7.60-7.47(m,3H),7.26(s,1H),7.21-7.0 1(m,1H),6.59(d,1H),6.44(d,1H),4.61-4.38(m,2H),3.49(q,2H),3.17-3.04(m,6H),2.11-2.04(m,3H),1.02(t,3H).

[0182] Step 4, 1.10 g (2.25 mmol) of compound 3d and 2.05 g (20.25 mmol) of triethylamine were dissolved in 30 mL of tetrahydrofuran and cooled to -10°C, and then 1.22 g (13.50 mmol) of acryloyl chloride was slowly added dropwise to the mixture, and the reaction system was stirred at room temperature for 12 h; after the reaction was completed, impurities were removed by suction filtration, and excess tetrahydrofuran was removed by rotary evaporation, and petroleum ether / ethyl acetate volume ratio = 3 / 1 was selected as the eluent for purification by silica gel column chromatography to obtain yellow oily liquid Rh-Ph with a yield of 75%.

[0183] Specifically, the molar ratio of compound 3d, acryloyl chloride, triethylamine and tetrahydrofuran is 1:9:6:164.

[0184] The NMR spectrum data of the yellow oily liquid Rh-Ph is as follows:

[0185] 1 H NMR(600MHz,DMSO-d6)δ8.70-8.37(m,1H),7.90(dd,2H),7.68(dd,2H),7.60 -7.48(m,3H),7.29(s,1H),7.08-7.03(m,1H),6.57(d,1H),6.43(s,1H),6.2 2(dd,1H),6.12-6.03(m,2H),5.86(dd,1H),5.79-5.72(m,2H),4.20(t,2H), 3.77-3.62(m,2H),3.36-3.26(m,3H),3.09(q,2H),2.00(s,3H),1.00(t,3H).

[0186] The mechanochromic luminescent elastomer of this embodiment is prepared by the same method as the mechanochromic luminescent elastomer in Embodiment 1, except that 0.058 g of Rh-Ph is used instead of 0.06 g of Rh-NEt2. Figure 5The normalized fluorescence emission spectra of the mechanochromic luminescent elastomer film of this embodiment at different stretching ratios are shown in Figure 4, with 430 nm selected as the normalized peak. It can be found that under external force stimulation, as the stretching ratio increases, the fluorescence emission peak intensity at 593 nm gradually increases, thereby proving that the mechanochromic luminescent elastomer prepared in Example 4 exhibits the property of mechanochromic luminescence.

[0187] Example 5

[0188] A rhodamine derivative Rh-PTZ with a mechanochromic effect, the chemical structure of the material is as shown in formula (6):

[0189]

[0190] The preparation reaction formula of the above-mentioned rhodamine derivative Rh-PTZ with mechanochromic effect is as follows:

[0191]

[0192] The preparation method of the rhodamine derivative Rh-PTZ with the above-mentioned mechanochromic effect is as follows:

[0193] Step 1, 4 g (13.3 mmol) of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid and 3.43 g (1.33 mmol) of N-ethyl-2-hydroxyphenothiazine were reacted in 30 mL of methanesulfonic acid at 90° C. for 6 hours; after the reaction, the mixture was neutralized with a saturated sodium carbonate solution, extracted three times with 50 mL of dichloromethane, the organic phase was collected, dried with anhydrous sodium sulfate, filtered, the filtrate was taken, the solvent was removed by rotary evaporation, and petroleum ether / ethyl acetate in a volume ratio of 1:1 was used as the eluent for purification by silica gel column chromatography to obtain a dark blue solid compound 1e with a yield of about 30%.

[0194] Specifically, the molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid, N-ethyl-2-hydroxyphenothiazine, and methanesulfonic acid is 1:1:35.5.

[0195] The NMR spectrum data of dark blue solid compound 1e are as follows:

[0196] 1 H NMR (400MHz, CDCl3) δ8.05(d,1H),7.68(m,2H),7.17(m,2H),7.06(d,1H),6.92(t,2H),6.74(s,1H),6. 47(s,1H),6.42(s,1H),6.38(s,1H),3.99(m,2H),3.27(m,2H),1.95(s,3H),1.52(t,3H),1.36(t,3H).

[0197] Step 2, 2.00 g (4.0 mmol) of compound 1e and 3.91 g (64.0 mmol) of ethanolamine were refluxed in 200 mL of ethanol at 90° C. for 48 hours; after the reaction, ethanol was removed by rotary evaporation, the crude product was dissolved with dichloromethane, extracted with deionized water, the organic phase was collected, dried by rotary evaporation, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 1:1 as the eluent to obtain a white solid compound 2e with a yield of about 67.5%.

[0198] Specifically, the molar ratio of compound 1e, ethanolamine, and ethanol is 1:16:862.

[0199] The NMR spectrum data of the white solid compound 2e are as follows:

[0200] 1 H NMR(400MHz, CDCl3)δ7.96(m,1H),7.45(m,2H),7.17(t,1H),7.06(m,2H),6.92(t,2H),6.68(s,1H),6.39(br,2H),6.33(s,1H) ,4.17(q,1H),3.99(q,2H),3.52(m,2H),3.36-3.19(br,4H),2.06(s,1H),1.97(s,3H),1.50(t,3H),1.38(t,3H),1.30(t,1H).

[0201] Step 3, 1.10 g (2.0 mmol) of compound 2e and 4.42 g (32.0 mmol) of potassium carbonate were reacted in 4.98 mL (64.0 mmol) of iodoethanol at 100° C. for 6 hours; after the reaction, the filtrate was filtered and water was added thereto, extracted three times with 50 mL of dichloromethane, the organic phase was collected, dried over anhydrous sodium sulfate, filtered, the filtrate was taken, and dried by spin drying, and purified by silica gel column chromatography using petroleum ether / ethyl acetate in a volume ratio of 1:2 as the eluent to obtain a white solid 3e with a yield of about 59%.

[0202] Specifically, the molar ratio of compound 2e, potassium carbonate and iodoethanol is 1:16:32.

[0203] The NMR spectrum data of white solid 3e are as follows:

[0204] 1H NMR (400MHz, CDCl3) δ7.96(m,1H),7.54(m,2H),7.16(t,1H),7.05(m,2H),6.93(m,3H),6.66(s,1H),6.49(s,1H),6.38(s,1H),3.97(t,3 H),3.91(m,1H),3.66(m,2H),3.52(m,2H),3.34(m,4H),3.03(s,2H),2.11(s,3H),1.71(br,1H),1.49(t,3H),1.28(m,3H),1.06(t,1H).

[0205] Step 4, 0.60 g (1.0 mmol) of compound 3e and 1.55 g (10 mmol) of isocyanoethyl methacrylate were dissolved in 20 mL of dichloromethane, and 20 μL (0.17 mmol) of dibutyltin dilaurate was slowly added dropwise to the mixture, and the reaction system was stirred at room temperature for 12 h; after the reaction, the excess dichloromethane was removed by rotary evaporation, and petroleum ether / ethyl acetate was used as the eluent for purification by silica gel column chromatography in a volume ratio of 2:1 to obtain white solid Rh-PTZ with a yield of about 68%.

[0206] Specifically, the molar ratio of compound 3e, isocyanoethyl methacrylate, dichloromethane, and dibutyltin dilaurate is 1:10:400:0.17.

[0207] The NMR spectrum data of white solid Rh-PTZ are as follows:

[0208] 1 H NMR(400MHz, CDCl3)δ8.01(d,2H),7.40(m,2H),7.06(t,3H),6.94(m,2H),6.82(t,3H),6.62(s,1H),6.34(d,2H),6.04(d,4H),5.51(d,4H) ,4.92(s,2H),4.78(s,1H),4.17(m,6H),4.00(m,3H),3.88(m,2H),3. 44-3.36(m,6H),3.20(m,2H),3.03(s,2H),1.82(m,12H),1.41(t,3H).

[0209] The mechanochromic luminescent elastomer of this embodiment is prepared by the same method as the mechanochromic luminescent elastomer in Embodiment 1, except that 0.023 g of Rh-PTZ is used instead of 0.06 g of Rh-NEt2. Figure 6The normalized fluorescence emission spectra of the mechanochromic luminescent elastomer film of this embodiment at different stretching ratios are shown in Figure 1, with a normalized peak at 450 nm. It can be found that under external force stimulation, as the stretching ratio increases, the fluorescence emission peak intensity at 610 nm gradually increases, thereby proving that the mechanochromic luminescent elastomer prepared in Example 5 exhibits the property of mechanochromic luminescence.

[0210] Example 6

[0211] The mechanochromic luminescent rhodamine derivative molecules are used to prepare the mechanochromic luminescent hydrogel, and the specific steps are as follows:

[0212] 0.562g 2-acrylamide-2-methylpropanesulfonic acid, 12.6mg N,N'-methylenebisacrylamide, 15.5mg ammonium persulfate were dissolved in 2.0mL deionized water, and then 1mol% of the monomer concentration of Rh-NEt2 synthesized in Example 1 was dissolved in 0.7mL dimethyl sulfoxide (DMSO). After the aqueous phase and DMSO phase were mixed, 0.04mL tetramethylethylenediamine was added as a catalyst. After mixing evenly, the solution was poured into a mold and cured at 50°C for 1 hour to obtain a cross-linked first layer network. Then, the prepolymer solution of the second layer was prepared, and 30.652g acrylamide, 0.6mg N,N'-methylenebisacrylamide, and 0.48mg I2959 were dissolved in 108mL sodium hydroxide solution with a pH of 12. After swelling for 20 minutes, the solution was taken out and cured under 365nm ultraviolet light for 1 hour to obtain a mechanochromic luminescent hydrogel film.

[0213] The film is clamped on a mold, and then the mold is placed in a fluorescence spectrometer to test its fluorescence changes during the stretching process. Figure 7 The normalized fluorescence emission spectra of the mechanochromic luminescent hydrogel prepared in Example 6 at different stretching ratios are shown in Figure 6, with a normalized peak of 427 nm. Under external force stimulation, the emission peak at 575 nm gradually becomes obvious, and as the stretching ratio increases, its emission position shows a more obvious red shift. When the stretching ratio is 2.0, the position of its emission peak has been red-shifted to 604 nm, and its fluorescence color becomes an obvious orange-red. This proves that the mechanochromic luminescent hydrogel prepared in Example 6 shows the properties of mechanochromic luminescence.

[0214] Example 7

[0215] The mechanochromic luminescent rhodamine derivative molecules are used to prepare thermoplastic mechanochromic luminescent polyurethane, and the specific steps are as follows:

[0216] First, 0.06 g of compound 3a synthesized in Example 1 was dissolved in 10 mL of N'N-dimethylformamide, 15 μL of dibutyltin laurate was added dropwise, and the mixture was stirred at room temperature for 1 h. 0.223 g of isophorone diisocyanate was added, and the mixture was heated at 80°C for 2 h. Then, 4 g of polytetrahydrofuran 2000 was added and the reaction was continued for 2 h. After 0.669 g of isophorone diisocyanate was added, the mixture was still reacted at 80°C for 2 h. Finally, 0.338 g of chain extender ureidopyrimidone was added, the mixture was heated to 100°C and reacted for 2 h, and then the mixture was cast in a mold, dried at 50°C for 24 h, and then taken out to obtain a mechanochromic luminescent thermoplastic elastomer film.

[0217] The film is clamped on a mold, and then the mold is placed in a fluorescence spectrometer to test its fluorescence changes during stretching. Figure 8 As shown in the figure, a new fluorescence emission peak appears at 584 nm when stretched, which proves that the thermoplastic mechanochromic luminescent polyurethane prepared in Example 7 exhibits the property of mechanochromic luminescence.

[0218] In order to illustrate the effectiveness of the method proposed in the present invention, a comparative experiment is conducted by using bifunctional and trifunctional rhodamine mechanochromic luminescent materials. The rhodamine mechanochromic luminescent material of the present invention is a bifunctional rhodamine molecule, which is added as a functional monomer to the main chain position of a thermoplastic polymer. The obtained thermoplastic mechanochromic luminescent polymer material is easy to process, has strong plasticity and is recyclable. The trifunctional rhodamine mechanochromic luminescent polymer (such as: ) can only be added as a cross-linking agent into the cross-linking sites of thermosetting polymers, which limits the processing performance and application scenarios of mechanochromic luminescent polymer materials.

[0219] Table 1 Rhodamine mechanochromic luminescent materials obtained in Examples 1-7 and their mechanoluminescent properties

[0220]

[0221] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A rhodamine mechanochromic luminescent material, characterized in that: Its chemical structure is any of the following: In formula (1), Z is H or methyl; Ar is a structure having an aromatic skeleton, and the structural formula having an aromatic skeleton is any one of the following: The Y1 is a substituent I, and Y2 is a substituent II. The chemical structural formulas of the substituent I and the substituent II are any of the following: Wherein, each of substituents I and II contains a polymerization site group, which is any one of R1 to R7; other R1 to R7 except the polymerization site group are independently H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; ● represents the position connected to N in formula (1); The polymerization site group is a substituent group III, and the chemical structural formula of the substituent group III is any one of the following: Wherein, W represents -C(O)O-, -OC(O)-, -C(O)NH- or -NHC(O)-; R8 is H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; R represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or an aryl group or a bond having 6 to 20 carbon atoms; ● represents the position of connection to the substituent Ⅱ.

2. A mechanochromic polymer material, characterized in that: The method is obtained by introducing the rhodamine mechanochromic luminescent material according to claim 1 into a polymer backbone through covalent bonding.

3. The mechanochromic polymer material according to claim 2, characterized in that: The polymer is a polymer elastomer, including polymethyl acrylate elastomer, polysiloxane elastomer, polymethacrylate glassy polymer, multi-network polymer, polyurethane polymer, polyurea polymer, polyolefin polymer, polyamide polymer, phenolic resin, epoxy resin, amino resin or polyacrylonitrile.

4. A method for preparing a rhodamine mechanochromic luminescent material, characterized in that: The following steps are involved: Step 1: 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid or 2-(4-(ethylamino)-2-hydroxybenzoyl)benzoic acid, phenol or a phenol derivative in which the ortho position of the phenolic hydroxyl group is H, and methanesulfonic acid are mixed to obtain a reaction system, and the system is subjected to heating reaction, pH neutralization, filtration, and purification to obtain compound 1; Step 2: Compound 1, Y2-substituted ammonia and ethanol are mixed to obtain a reaction system, and the mixture is subjected to heating reflux reaction, rotary evaporation, extraction and purification to obtain compound 2; Step 3: Compound 2, Y1-substituted halide and potassium carbonate are mixed to obtain a reaction system, and compound 3 is obtained by heating, reacting, filtering, extracting and purifying; Wherein, Y1 is substituent I, Y2 is substituent II, and the chemical structural formulas of substituent I and substituent II are any of the following: Wherein, each of substituents I and II contains a polymerization site group, which is any one of R1 to R7; other R1 to R7 except the polymerization site group are independently H, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; ● represents the position connected to N in formula (1); The polymerization site group is a substituent group III, and the chemical structural formula of the substituent group III is any one of the following: Wherein, W represents -C(O)O-, -OC(O)-, -C(O)NH- or -NHC(O)-; R8 is H, and a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, F, Cl, Br, I, CF3, CCl3 or OCH3; R represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or an aryl group or a bond having 6 to 20 carbon atoms; ● represents the position of connection to substituent I or substituent II.

5. The preparation method according to claim 4, characterized in that: The phenol derivative in which the ortho position of the phenolic hydroxyl group is H is one of the following:

6. The preparation method according to claim 4, characterized in that: In step 1: The molar ratio of 2-(4-(ethylamino)-2-hydroxy-5-methylbenzoyl)benzoic acid or 2-(4-(ethylamino)-2-hydroxybenzoyl)benzoic acid, phenol or a phenol derivative with H at the ortho position of the phenolic hydroxyl group, and methanesulfonic acid is 1 mol: 1-2 mol: 30-40 mol; the heating reaction temperature is 80-100° C.; the heating reaction time is 12-24 h; the purification is column chromatography purification, and the column chromatography purification eluent is dichloromethane and methanol; The volume ratio of dichloromethane:methanol is 20-40:

1.

7. The preparation method according to claim 4, characterized in that: In step 2: The molar ratio of compound 1 and Y2-substituted ammonia and ethanol is 1 mol: 2-20 mol: 50-900 mol; the temperature of the heating reflux reaction is 80-100°C; the heating reflux reaction time is 24-48 hours; the purification is column chromatography purification, and the column chromatography purification eluent is petroleum ether and ethyl acetate or dichloromethane and methanol; the volume ratio of petroleum ether and ethyl acetate is 1-4:1; the volume ratio of dichloromethane: methanol is 30-40:

1.

8. The preparation method according to claim 4, characterized in that: In the step 3: the halogen atom in the Y1-substituted halide is I or Br; the molar ratio of compound 2, Y1-substituted halide and potassium carbonate is 1 mol: 20-40 mol: 8-16 mol; the heating reaction temperature is 80-100°C; the heating reaction time is 4-8h; the purification is column chromatography purification, and the column chromatography purification eluent is petroleum ether and ethyl acetate or dichloromethane and methanol; the volume ratio of petroleum ether: ethyl acetate is 0.5-4: 1; the volume ratio of dichloromethane: methanol is 20-40:

1.

9. The preparation method according to claim 4, characterized in that: The method further comprises step 4: modifying compound 3 by changing Y1 and / or Y2 to meet application requirements.

10. A use of the rhodamine mechanochromic luminescent material as claimed in claim 1, characterized in that: It is used in mechanochromic luminescent hydrogels, mechanochromic luminescent elastomers, thermoplastic mechanochromic luminescent polyurethanes, probes, stress detection, failure analysis, intelligent display and damage warning.

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