Dehydroabietic acid-based aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) dual-characteristic compound as well as preparation method and application thereof

Abstract

The invention discloses a dehydroabietic acid-based aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) dual-characteristic compound as well as a preparation method and an application of the dehydroabietic acid-based aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) dual-characteristic compound. The structural formula of the dehydroabietic acid-based aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) dual-characteristic compound is # imgabs0. The dehydroabietic acid-based aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) dual-characteristic compound disclosed by the invention is formed by 12-[N, N-dimethyl formamide], the 2-(benzo [d] thiazole-2-yl)-4-bromophenol compound is prepared by reacting N, N-p-methoxy-4-boric acid ester phenyl] amino-dehydroabietic acid methyl ester with 2-(benzo [d] thiazole-2-yl)-4-bromophenol. The dehydroabietic acid-based aggregation-induced emission (AIE) and excited state intramolecular proton transfer (ESIPT) dual-characteristic compound DTPA-HBT provided by the invention has large Stokes shift, can be used for fluorescence imaging, and can also be applied to fluorescence anti-counterfeiting; the synthesis route is mild, controllable and easy to operate.

Description

Technical Field

[0001] The invention relates to a dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound, a preparation method and application thereof, and belongs to the technical field of organic fluorescent molecule synthesis and functional materials. Background Art

[0002] Traditional organic fluorescent dyes often experience aggregation-induced quenching (ACQ) in the aggregated state, which limits their practical applications. Aggregation-induced emission (AIE) fundamentally solves this problem.

[0003] Excited state intramolecular proton transfer (ESIPT) refers to the proton transfer process between adjacent proton donors and proton acceptors in a molecule due to the enhancement of hydrogen bonds when the molecule is excited by light. In the excited state, ESIPT molecules can achieve structural transformation through intramolecular proton transfer, forming a large Stokes shift, which leads to a significant change in the fluorescence wavelength, different luminescence states, and effectively avoid self-absorption.

[0004] Combining ESIPT with AIE properties provides new possibilities for the development of new luminescent materials. However, the types of fluorescent molecules with ESIPT and AIE effects are very limited, especially those based on disproportionate rosin, which have both ESIPT and AIE properties. There are only a few simple Schiff base compounds with limited structural diversity, and there are only a few known examples. The quantum yield in the solid state is low (<4%), and some are even as low as 0.3%. In addition, these compounds are of a single type, with a short emission wavelength and limited Stokes shift, and rarely show the synergistic effect between AIE and ESIPT.

[0005] Dehydroabietic acid is obtained by catalytic disproportionation and purification of rosin. It contains an aromatic ring in its skeleton. Based on the aromatic ring and the carboxylic acid group, a variety of fluorescent derivatives can be developed, which opens up a new way for the high-value utilization of rosin. However, its ACQ effect and short emission wavelength limit its application. To solve this problem, the present invention combines dehydroabietic acid derivatives with 2-(2-hydroxyphenyl)benzothiazole, and through the design of a specific structure, not only does it have a large Stokes shift, but it also achieves the expansion of dehydroabietic acid derivatives from high-energy blue light emission to low-energy orange light emission, and exhibits obvious synergistic effects between AIE and ESIPT. Summary of the invention

[0006] The invention provides a dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound, a preparation method and an application thereof. The compound has aggregation-induced emission enhancement characteristics and excited-state intramolecular proton transfer characteristics, has a large Stokes shift, can be used for fluorescence imaging, and can also be used for fluorescence anti-counterfeiting.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound has the dual effects of aggregation-induced emission enhancement effect and excited-state intramolecular proton transfer; the structural formula of the dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound is:

[0009]

[0010] The above-mentioned dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-characteristic compound is named DTPA-HBT; the hydroxyl group (-OH) acts as a proton donor, the nitrogen atom (N) on the thiazole ring acts as a proton acceptor, and an effective hydrogen bond is formed within the molecule to enable the excited-state proton transfer process to occur, showing the ESIPT characteristic; the π-π stacking of the molecules is hindered in the aggregated state, so that the fluorescence emission is enhanced, showing obvious AIE characteristics; there is an obvious synergistic effect between the two characteristics. On the one hand, in the biocompatible organic solvent DMSO and ethanol / water (v:v=3 / 7), the fluorescence quantum yield is 3.28 and 1.24 times that of the solid-state quantum yield, respectively. On the other hand, the Stokes shift can reach 280nm, which effectively avoids self-absorption and internal filtration effects, is conducive to fluorescence imaging, and can be used as an AIE probe for cell imaging; at the same time, it has the potential of invisible ink, can be used for fluorescent anti-counterfeiting, is long-lasting and stable, and effectively extends the fluorescent anti-counterfeiting period.

[0011] The synthesis route of the above-mentioned dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound is as follows:

[0012]

[0013] The preparation method of the above-mentioned dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound is as follows: under nitrogen protection, 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester and 2-(benzo[d]thiazol-2-yl)-4-bromophenol are used as raw materials, potassium carbonate and tetrakis(triphenylphosphine)palladium are added, and Suzuki coupling reaction is carried out in a tetrahydrofuran / water system. After the reaction is completed, the compound is cooled and purified to obtain the compound DTPA-HBT.

[0014] In order to ensure the purity of the product, the product is purified according to the following method: after cooling, the product is sequentially extracted with dichloromethane and water, the organic phase is collected, dried with anhydrous magnesium sulfate, separated and purified by column chromatography, and then evaporated and dried to obtain the AIE / ESIPT dual-property compound DTPA-HBT. When separated and purified by column chromatography, the eluent used is preferably a mixture of petroleum ether and ethyl acetate in a volume ratio of (24-26):1.

[0015] In order to improve the product yield, the molar ratio of 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester to 2-(benzo[d]thiazol-2-yl)-4-bromophenol is 1:(1-1.1), more preferably 1:1.1.

[0016] In order to further improve the product yield, the molar ratio of 2-(benzo[d]thiazol-2-yl)-4-bromophenol, potassium carbonate and tetrakis(triphenylphosphine)palladium is (1-1.1):(1-1.2):(0.02-0.03), and more preferably 1.1:1.2:0.03.

[0017] In order to improve the reaction efficiency, the solvent is a mixed solution of tetrahydrofuran and water, the reaction temperature is 35-45° C., and the reaction time is 36-48 hours.

[0018] The above-mentioned 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester can be prepared by the following method: 12-[N,N-p-methoxy-4-bromophenyl]amino-dehydroabietic acid methyl ester and bis(pinacolato)diboron are dissolved in dimethyl sulfoxide, nitrogen is introduced for protection, potassium acetate and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex are added, the reaction is carried out at a temperature of 70 to 80° C. for 20 to 24 hours, the reaction is cooled, and the reaction is carried out with dichloromethane and water. The organic phase is collected, dried over anhydrous magnesium sulfate, separated and purified by column chromatography, the solvent is removed by rotary evaporation, and vacuum drying is carried out to obtain white solid 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester.

[0019] The molar ratio of the above-mentioned 12-[N,N-p-methoxy-4-bromophenyl]amino-dehydroabietic acid methyl ester, bis(pinacol)diboron, potassium acetate and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex is 1:(1.8-2):(3.5-4):(0.04-0.06).

[0020] The above 12-[N,N-p-methoxy-4-bromophenyl]amino-dehydroabietic acid methyl ester can be prepared by the following method: 12-[N,N-(4-methoxy)-phenyl]amino-dehydroabietic acid methyl ester (DTPA), NBS (N-bromosuccinimide) and anhydrous acetonitrile are added to a round-bottom flask, reacted at 20-25° C. in the dark for 18-24 hours, rotary evaporated, purified, and dried to obtain white solid 12-[N,N-(4-methoxy)-(4-bromophenyl)]amino-dehydroabietic acid methyl ester (DTPA-Br), which is stored in a desiccator for later use. The molar ratio of 12-[N,N-(4-methoxy)-phenyl]amino-dehydroabietic acid methyl ester (DTPA) to NBS (N-bromosuccinimide) is 1: (1-1.1).

[0021] The above-mentioned 12-[N, N-(4-methoxy)-phenyl]amino-dehydroabietic acid methyl ester (DTPA) can be prepared by the following method: 12-(phenyl)amino-dehydroabietic acid methyl ester (DDPA) and p-bromoanisole are added to a three-necked flask, anhydrous o-xylene is added, nitrogen is passed through, sodium tert-butoxide, tri-tert-butylphosphine and palladium acetate are added, heating reflux reaction is carried out for 8 to 12 hours, and ether and water are used for extraction. The organic phase is collected, dried over anhydrous magnesium sulfate, separated and purified by column chromatography, and the solvent is removed by rotary evaporation, and then placed in a vacuum drying oven at 60 to 65° C. for vacuum drying for 10 to 12 hours to obtain a light yellow solid 12-[N, N-(4-methoxy)-phenyl]amino-dehydroabietic acid methyl ester (DTPA), which is stored in a dryer for use. Among them, the molar ratio of 12-(phenyl)amino-dehydroabietic acid methyl ester (DDPA), p-bromoanisole, sodium tert-butoxide, tri-tert-butylphosphine and palladium acetate is 1: (1.1-1.2): (1.41-1.45): (0.10-0.12): (0.01-0.03).

[0022] The above-mentioned 2-(benzo[d]thiazol-2-yl)-4-bromophenol can be prepared by the following method: 5-bromosalicylaldehyde and o-aminothiophenol are dissolved in water, aminosulfonic acid is added, and the mixture is stirred at room temperature for 0.5 to 1 hour. The crude product is filtered and washed with water to obtain a crude product, and then recrystallized from a water-ethanol mixed solvent to obtain a yellow solid 2-(benzo[d]thiazol-2-yl)-4-bromophenol.

[0023] The molar ratio of the above 5-bromosalicylaldehyde to o-aminothiophenol and aminosulfonic acid is: 1: (1-1.1): (0.03-0.04).

[0024] The technologies not mentioned in the present invention are all referred to the prior art.

[0025] Beneficial Effects

[0026] (1) The present invention starts from a dehydroabietic acid derivative to synthesize a compound with a novel structure and both AIE and ESIPT properties, showing obvious synergistic effects between AIE and ESIPT. The synthetic route is mild, controllable and easy to operate.

[0027] (2) The dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound DTPA-HBT provided by the present invention has a fluorescence quantum yield in a relatively mild and biocompatible organic solvent (DMSO or ethanol / water mixed solution) that is 1 to 4 times higher than that in the solid state, and a maximum Stokes shift of up to 280 nm. It can effectively avoid or reduce background interference and self-absorption, reduce phototoxicity, enhance tissue penetration depth, improve display quality, and facilitate cell imaging.

[0028] (3) The dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound DTPA-HBT provided by the present invention has obvious aggregation-induced emission enhancement properties, and has the characteristics of double and triple emission. In addition, it has a more three-dimensional configuration and a plane that is conducive to proton transfer in the excited state, which is conducive to AIE and ESIPT characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The DTPA-HBT of the present invention 1 H NMR spectrum;

[0030] Figure 2 The DTPA-HBT of the present invention 13 C NMR spectrum;

[0031] Figure 3 is a high resolution mass spectrum (HRMS) of DTPA-HBT of the present invention;

[0032] Figure 4 The UV absorption spectra of DTPA-HBT in different solutions (1×10 -5 mol / L);

[0033] Figure 5 The fluorescence emission spectra of DTPA-HBT in different solutions (1×10 -5 mol / L), the excitation wavelength is 340nm;

[0034] Figure 6The DTPA-HBT of the present invention is in different water volume fractions (f w ) in ethanol / water mixed solvent (1×10 -5 mol / L), and the illustrations are f w =0% and f w =Photograph of 70% DTPA-HBT solution under 365nm UV irradiation;

[0035] Figure 7 The relationship between the fluorescence intensity I / I0 of DTPA-HBT and the water content of the present invention (I0 is the compound at f w = 0% solution fluorescence emission intensity, I is the compound in the corresponding f w = fluorescence emission intensity at 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%);

[0036] Figure 8 is a graph showing the relationship between the DTPA-HBT nanoparticle size (DLS) and different water contents of the present invention;

[0037] Fig. 9 The DTPA-HBT of the present invention is w =0% and f w = Tyndall experiment photo at 70%;

[0038] Fig.10 The structural optimization diagrams of the DTPA-HBT in the ground state (S0) and the excited state (S1) calculated by the density functional theory and the time-dependent density functional theory method of the DTPA-HBT of the present invention;

[0039] Fig.11 The lowest unoccupied orbital energy level (LUMO) and the highest occupied orbital energy level (HOMO) of the DTPA-HBT of the present invention in the ground state (S0) and the excited state (S1);

[0040] Fig.12 : is the dihedral angle diagram of DTPA-HBT of the present invention in the ground state (S0) and the excited state (S1);

[0041] Fig.13 It is a visual diagram of planarity analysis of DTPA-HBT of the present invention in the ground state (S0) and the excited state (S1);

[0042] Fig.14 The four-level energy level mechanism diagram of the tautomerism between the enol form and the keto form of DTPA-HBT caused by the excited state intramolecular proton transfer of the present invention;

[0043] Fig.15 This is a fluorescent anti-counterfeiting effect diagram of the DTPA-HBT solution of the present invention.

[0044] Fig.16 This is a picture showing the effect of the DTPA-HBT fluorescent anti-counterfeiting of the present invention under 365nm ultraviolet light after being placed for 72 days. DETAILED DESCRIPTION

[0045] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0046] Example 1

[0047] A dehydroabietic acid-based compound with dual properties of aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT), the synthesis route of which is:

[0048]

[0049] The preparation process is as follows:

[0050] 1 mmol of 12-bromodehydroabietic acid methyl ester (DA) (Tan Guanni, et al. Synthesis and spectral properties of dehydroabietic acid triarylamine compounds containing naphthalene [J]. Chemistry and Industry of Forest Products, 2019, 39(1): 61-66.) and 1.2 mmol of aniline were dissolved in 10 mL of anhydrous o-xylene. After deoxygenation for 15 minutes under nitrogen atmosphere, 1.44 mmol of sodium tert-butoxide (t-BuONa), 0.12 mmol of tri-tert-butylphosphine (P(t-Bu)3) and 0.03 mmol of palladium acetate (Pd(OAc)2) were added. The mixture was heated to reflux at 140°C for 12 h, cooled, extracted with ether and saturated brine, and the organic phase was collected, dried over anhydrous magnesium sulfate, and purified by column chromatography (eluent, V 石油醚 :V 乙酸乙酯 =10:1), after removing the solvent by rotary evaporation, the mixture was placed in a vacuum drying oven at 65°C for 12 h to obtain a light yellow solid 12-(phenyl)amino-dehydroabietic acid methyl ester (DDPA), which was stored in a desiccator for later use.

[0051] 1mmol 12-(phenyl)amino-dehydroabietic acid methyl ester (DDPA) and 1.2mmol p-bromoanisole were added to a three-necked flask, and 10mL of anhydrous o-xylene was added. Under nitrogen protection, 1.44mmol sodium tert-butoxide, 0.12mmol tri-tert-butylphosphine and 0.03mmol palladium acetate were added. The mixture was heated under reflux for 12h, extracted with ether and water, and the organic phase was collected, dried over anhydrous magnesium sulfate, and purified by column chromatography (eluent, V 石油醚 :V 乙酸乙酯=25:1), the solvent was removed by rotary evaporation and then placed in a vacuum drying oven at 65°C for 12 h to obtain a light yellow solid 12-[N,N-(4-methoxy)-phenyl]amino-dehydroabietic acid methyl ester (DTPA), which was stored in a desiccator for later use.

[0052] 1 mmol 12-[N, N-(4-methoxy)-phenyl]amino-dehydroabietic acid methyl ester (DTPA), 1 mmol NBS (N-bromosuccinimide), and 25 mL anhydrous acetonitrile were added to a round-bottom flask, and the mixture was reacted at 25°C in the dark for 24 h, and then rotary evaporated and purified by column chromatography (eluent, V 石油醚 :V 乙酸乙酯 =20:1), the solvent was removed by rotary evaporation and then placed in a vacuum drying oven at 65°C for 12 h to obtain a white solid 12-[N,N-(4-methoxy)-(4-bromophenyl)]amino-dehydroabietic acid methyl ester (DTPA-Br), which was stored in a desiccator for later use.

[0053] 1 mmol 12-[N,N-p-methoxy-4-bromophenyl]amino-dehydroabietic acid methyl ester (DTPA-Br) was added to a DMSO (15 mL) solution of 2 mmol bis(pinacolato)diboron, 0.06 mmol Pd(dppf)Cl2·CH2Cl2 and 4 mmol potassium acetate, and the mixture was stirred at 80°C for 24 h under nitrogen. The mixture was extracted with dichloromethane and water, and the organic phase was collected, dried over anhydrous magnesium sulfate, and purified by column chromatography (eluent, V 石油醚 :V 乙酸乙酯 =20:1), the solvent was removed by rotary evaporation, and the mixture was dried in vacuo to obtain a white solid 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester (DTPA-Bpin) with a yield of 73.1%.

[0054] Dissolve 1 mmol 5-bromosalicylaldehyde and 1 mmol o-aminothiophenol in 5 mL water, add 0.04 mmol aminosulfonic acid, stir at room temperature for 1 h, filter and wash with water, and recrystallize the solid from water or a water-ethanol mixed solvent to obtain a yellow solid 2-(benzo[d]thiazol-2-yl)-4-bromophenol (HBT-Br). This step is a green synthesis method with a yield of 99.9%.

[0055] 1 mmol 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester (DTPA-Bpin), 1.1 mmol 2-(benzo[d]thiazol-2-yl)-4-bromophenol (HBT-Br), and 1.2 mmol potassium carbonate (K2CO3) were dissolved in a mixed solution of 20 mL tetrahydrofuran and 5 mL water. Under a nitrogen atmosphere, 0.03 mmol tetrakis(triphenylphosphine)palladium was added, and the mixture was heated to reflux at 45°C for 48 h, cooled, extracted with dichloromethane and water, and the organic phase was collected, dried over anhydrous magnesium sulfate, and purified by column chromatography (eluent, V 石油醚 :V 乙酸乙酯 =25:1), after the solvent was removed by rotary evaporation, the mixture was placed in a vacuum oven at 60°C for 12 hours to obtain yellow solid DTPA-HBT with a yield of 51.3%. The solid quantum yield of yellow solid DTPA-HBT was 7.80%; the quantum yield in pure ethanol solution was 1.96%, the quantum yield in ethanol / water (v:v=3 / 7) mixed solution was 9.71%, and the quantum yield in DMSO was 25.62%. The quantum yields in different solvents were all at a concentration of 10 -6 Measured under the conditions of mol / L.

[0056] like Figures 1 to 3 As shown, the characterization data: 1 H NMR (500MHz, DMSO-d6) δ11.54(s,1H),8.34(s,1H),8.14(d,J=8.0Hz,1H),8.07(d,J=8.2Hz,1H),7.63(d,J=8.7Hz,1H),7.54(t,J=7.7Hz, 1H),7.46(dd,J=20.1,8.2Hz,3H),7.13(d,J=8.5Hz,1H),7.06(s,1H),7.00(d,J=6.9Hz,3H),6.89(d,J=9.0Hz,2H),6.78(d,J=8.7Hz,2H) ,3.73(s,3H),3.62(s,3H),3.04(p,J=6.8Hz,1H),2.91(dd,J=17.8,6.8Hz,1H),2.81(q,J=8.4,7.8Hz,1H),2.09(dd,J=24.8,12.1Hz,2H) ,1.86-1.75(m,1H),1.66(d,J=9.6Hz,2H),1.58-1.54(m,1H),1.33(s,1H),1.25(d,J=3.1Hz,2H),1.19(s,3H),1.13(s,3H),0.96(s,6H). 13C NMR (126MHz, DMSO-d6) δ177.93,164.74,155.07,154.83,151.42,148.57,147.65,145.60,143.56,141.01, 139.81,134.51,133.30,131.75,130.15,130.05,127.56,126.70,126.38,125.25,124.99,124.52,122.13 ,121.92,118.71,118.15,117.46,114.58,55.16,51.83,46.88,44.53,40.02,39.85,39.69,39.35,39.19, 39.02,37.57,36.47,36.11,29.20,26.80,24.80,23.38,23.29,21.03,17.83,16.21.HRMS(ESI):calc.for C 47 H 48 N2O4S,[M+H] + :737.3335; found,737.34094.

[0057] like Figure 4-5 As shown in the figure, the maximum absorption wavelength of the dual-characteristic compound DTPA-HBT with aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) of dehydroabietic acid is around 320nm in different solvents, while the fluorescence emission spectrum varies greatly. The appearance of double or triple fluorescence peaks and large Stokes shift caused by proton transfer reflects the ESIPT characteristics of the molecule, with a maximum Stokes shift of 280nm. The short-wavelength emission near 410nm is the emission peak of the enol form, the long-wavelength emission near 580nm belongs to the fluorescence emission of the keto isomer, and the emission peak near 520nm is the intermediate state emission formed by the interaction between the molecule and the solvent.

[0058] like Figure 6-7 As shown in the figure, DTPA-HBT has a typical aggregation-induced emission enhancement effect, that is, as the water content increases, its fluorescence emission intensity increases. When the water content is less than 50%, the enol fluorescence emission at 415nm is dominant. When the water content is greater than 60%, the molecular aggregation leads to the restriction of molecular motion, and the ESIPT effect is activated, mainly with the keto fluorescence emission peak at 585nm, indicating that molecular aggregation is conducive to the proton transfer process. The stronger the keto fluorescence emission caused by the proton transfer process, the stronger the AIE characteristics. The change process of the entire spectral behavior reflects the obvious synergistic effect between the two characteristics of AIE and ESIPT.

[0059] like Figure 8 As shown in the figure, with the increase of water content, the change of aggregate size indicates that the aggregation state of DTPA-HBT has been changing.

[0060] like Fig. 9 As shown, the water content f w =70% Tyndall effect indicates that DTPA-HBT forms aggregates.

[0061] like Fig.10 As shown, after DTPA-HBT is excited, the molecular configuration is twisted.

[0062] like Fig.11 As shown, the proton transfer process is often accompanied by electron transition. The energy gap value of the molecule is related to the chemical reactivity and kinetic stability. The energy gap value of DTPA-HBT in the excited state is 2.39eV, which is smaller than the energy gap value of the ground state of 3.07eV, indicating that the molecule is more likely to undergo electron transition in the excited state, which is beneficial to the proton transfer process.

[0063] like Fig.12 As shown, the dihedral angle between planes 5 and 6 related to the intramolecular hydrogen bond decreases from 0.35° in the ground state to 0.31° in the excited state, indicating that the planarity between 5 and 6 is better in the excited state, which is more conducive to proton transfer and ESIPT characteristics.

[0064] like Fig.13 As shown in the figure, the molecular planarity parameter (MPP) and the deviation from the plane span (SDP) parameters are used to characterize the planarity of the molecule. The smaller the value, the better the planarity. The MPP and SDP values ​​in the ground state are both smaller than those in the excited state, indicating that the configuration in the excited state is more twisted. The twisted spatial configuration inhibits the tight π-π stacking and non-radiative transition in the aggregated state, and is also more conducive to the AIE characteristics.

[0065] like Fig.14 As shown, the four-level energy diagram of the DTPA-HBT molecule reveals the mechanism of tautomerism between the enol form and the keto form.

[0066] Application Example 1

[0067] Take 7.36 mg of DTPA-HBT and place it in a 10 ml volumetric flask. Dilute it with dichloromethane to a concentration of 1×10 -3 mol / L stock solution; use a pipette to transfer 1000 μL of the stock solution into a 10 ml volumetric flask, and then use dichloromethane to make up to 10 ml, to obtain a concentration of 1×10 -4ml / L of test solution. Take the above test solution with a capillary sample tube of 2mm diameter, write the letter "HBT" on the practice banknote without fluorescent background, and take pictures of the practice banknote under natural light, 365nm ultraviolet irradiation, 365nm ultraviolet irradiation for 30min, and 365nm ultraviolet irradiation after being placed in natural environment for 7 days. The results are as follows Fig.15 As shown, the mark is not visible in daylight ( Fig.15 b), but visible under 365nm ultraviolet light ( Fig.15 d), indicating that the compound can be used as invisible fluorescent ink; in addition, whether it is naturally placed for 7 days and then irradiated or continuously irradiated for 30 minutes, the written fluorescent mark can still be observed ( Fig.15 ef), after 30 days in natural environment, the fluorescence intensity observed was no different from that on the 7th day when irradiated with 365nm ultraviolet light. In addition, after 72 days in natural environment, obvious fluorescence was still observed when irradiated with 365nm ultraviolet light ( Fig.16 ), indicating that DTPA-HBT has good stability. In summary, DTPA-HBT can be used as invisible ink for fluorescent anti-counterfeiting.

Claims

1. A dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound, characterized in that: It has the dual effects of aggregation-induced emission enhancement and excited-state intramolecular proton transfer, and its structural formula is:

2. A method for preparing the dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound according to claim 1, characterized in that: The synthetic route is as follows:

3. The preparation method according to claim 2, characterized in that: Under nitrogen protection, 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester and 2-(benzo[d]thiazol-2-yl)-4-bromophenol were used as raw materials, potassium carbonate and tetrakis(triphenylphosphine)palladium were added, and Suzuki coupling reaction was carried out in a nitrogen atmosphere. After the reaction, the product was cooled and purified to obtain the AIE / ESIPT dual-property compound DTPA-HBT.

4. The preparation method according to claim 3, characterized in that: The molar ratio of 12-[N,N-p-methoxy-4-boronate phenyl]amino-dehydroabietic acid methyl ester to 2-(benzo[d]thiazol-2-yl)-4-bromophenol, potassium carbonate and tetrakis(triphenylphosphine)palladium is 1:(1-1.1):(1-1.2):(0.02-0.03).

5. The preparation method according to claim 3 or 4, characterized in that: The Suzuki coupling reaction is carried out in a mixed solution of tetrahydrofuran and water, the reaction temperature is 35-45°C, and the reaction time is 36-48h.

6. The preparation method according to claim 3 or 4, characterized in that: The purification process is as follows: the cooled material is extracted with dichloromethane and water, the organic phase is collected, and then dried over anhydrous magnesium sulfate, separated and purified by column chromatography, rotary evaporated and dried to obtain the AIE / ESIPT dual-property compound DTPA-HBT; the eluent used for column chromatography separation and purification is a mixture of petroleum ether and ethyl acetate in a volume ratio of (24-26):

1.

7. The preparation method according to claim 3 or 4, characterized in that: The preparation method of 12-[N,N-p-methoxy-4-borylphenyl]amino-dehydroabietic acid methyl ester is as follows: 12-[N,N-p-methoxy-4-bromophenyl]amino-dehydroabietic acid methyl ester and bis(pinacolato)diboron are dissolved in dimethyl sulfoxide, nitrogen is introduced for protection, potassium acetate and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex are added, the reaction is carried out at a temperature of 70 to 80° C. for 20 to 24 hours, the reaction is cooled, and the reaction is extracted with dichloromethane and water, the organic phase is collected, dried over anhydrous magnesium sulfate, separated and purified by column chromatography, the solvent is removed by rotary evaporation, and vacuum drying is carried out to obtain 12-[N,N-p-methoxy-4-borylphenyl]amino-dehydroabietic acid methyl ester as a white solid.

8. The preparation method according to claim 7, characterized in that: The molar ratio of 12-[N,N-p-methoxy-4-bromophenyl]amino-dehydroabietic acid methyl ester, bis(pinacol)diboron, potassium acetate and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex is 1:(1.8-2):(3.5-4):(0.04-0.06).

9. The preparation method according to claim 3 or 4, characterized in that: The preparation method of 2-(benzo[d]thiazol-2-yl)-4-bromophenol is as follows: 5-bromosalicylaldehyde and o-aminothiophenol are dissolved in water, aminosulfonic acid is added, and the mixture is stirred at room temperature for 0.5 to 1 hour, filtered and washed with water to obtain a crude product, and then recrystallized through a water-ethanol mixed solvent to obtain a yellow solid 2-(benzo[d]thiazol-2-yl)-4-bromophenol; the molar ratio of 5-bromosalicylaldehyde to o-aminothiophenol to aminosulfonic acid is: 1:(1 to 1.1):(0.03 to 0.04).

10. Use of the dehydroabietic acid-based aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) dual-property compound according to claim 1, characterized in that: The large Stokes shift of this compound can avoid self-absorption, and the high fluorescence quantum yield in biocompatible solvents helps to improve the imaging effect, making it suitable for fluorescence imaging; or its photochromic properties can be used as a fluorescent dye for fluorescent anti-counterfeiting.

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