Preparation and application of D-A type organic molecular stimuli-responsive material

Abstract

The invention belongs to the field of organic photoelectric materials, and discloses preparation and application of a D-A type organic molecular motor stimulation material. Based on a donor-receptor configuration, the compound has the following structure: # imgabs0 #, wherein Ar is N, N-dimethylaniline and a derivative thereof. According to the invention, an imino indole group is introduced to one end of a donor N, N-dimethylaniline and a derivative thereof, so that a donor-acceptor and a charge transfer state are constructed, and meanwhile, non-radiative transition of molecules in an aggregation state is inhibited, so that the material is endowed with the property of AIE. In addition, due to the introduction of a C = N bond, the material shows an excellent molecular motor characteristic, and has a photoresponse phenomenon of donor rotation under optical excitation. After the trifluoroacetic acid proton-donating acidic material is added, the absorption spectrum is faded or the absorption wavelength is subjected to red shift. The material provided by the invention has efficient light and acid response capability, and has good application prospects in the aspects of information storage, optical signal transmission and information encryption.

Description

Technical Field

[0001] The invention belongs to the field of photoelectric materials, and particularly relates to the preparation and application of DA type organic molecule stimulus response materials. Background Art

[0002] Materials, as the fundamental material support for human survival and development, constitute a strong source of power to promote the continuous evolution of human society. They are closely related to the vigorous construction of the national economy, the solid construction of national defense forces, and the diverse forms of people's lives. People's demand for materials has undergone profound changes, gradually transitioning from the traditional structural materials to the field of intelligent materials. Stimulus-responsive color-changing materials, as a key branch category in the intelligent material system, undoubtedly play a vital and incomparable role in the panorama of social life and the social production pattern of today's era. Its influence has widely penetrated into the innovation and development process of many industries and fields, and has become one of the core elements in shaping the material and technological landscape of modern society.

[0003] Stimulus-responsive color-changing materials are a type of material whose optical properties, such as absorption, transmittance, reflectivity, color, and fluorescence emission wavelength, change significantly under specific external stimuli such as light, electricity, heat, force, acid / base, and humidity. In view of its wide application prospects in many fields such as information storage, anti-counterfeiting, green printing, smart organic light-emitting diodes (OLEDs), and sensors, this material has attracted more and more attention and has achieved extremely remarkable development results. According to the differences in the types of external stimuli, stimulus-responsive color-changing materials can be mainly divided into photochromic, mechanochromic, electrochromic, thermochromic, and acid-base color-changing categories.

[0004] Among all kinds of stimulus-responsive color-changing materials, photochromic materials have unique properties. Specifically, when such materials are stimulated by external light, their photophysical properties, such as transmittance, color or luminescence wavelength, will change significantly, and they can be restored to their original state under the action of another specific wavelength of light or heating treatment. For photochromic materials, indicators such as response rate and anti-fatigue properties constitute the main parameter basis for measuring the quality of the photochromic performance of the material. With their unique performance advantages, these compounds have been widely used in many important fields such as sensors, information storage and anti-counterfeiting.

[0005] Acid color change is a special response phenomenon. When certain substances are in an acidic environment, the hydrogen ions provided by the acidic substances will react with the target substances. This may lead to changes in chemical bonds within the molecule, readjustments in the distribution of the electron cloud, or changes in the molecular conformation. These microscopic changes will cause differences in the absorption and reflection of light of different wavelengths by the substance, and the color originally presented by the absorption and reflection of specific light will change, thereby intuitively showing the wonderful effect of acid color change, which is of great significance in many fields such as chemical analysis and sensor development. Summary of the invention

[0006] In response to the above problems, we will design and synthesize a class of materials that absorb near-infrared wavelengths and enhance low-temperature near-infrared emission, are AIE-type molecular motors, and respond to trifluoroacetic acid. Based on the iminoindole group as an acceptor, we will use the donor to enhance the conjugated chain length, intramolecular charge transfer and other mechanisms to achieve the preparation of stimulus-responsive materials that absorb near-infrared. At the same time, we will explore its molecular motor mechanism with the help of transient absorption spectroscopy, and realize the basic application of information encryption and erasure by combining it with PMMA.

[0007] To achieve the above object, the present invention provides the following technical solution: preparation and application of a DA type organic molecule stimulus responsive material, the preparation method of which comprises the following steps:

[0008] In a nitrogen atmosphere, a nitroso-containing electron-donating compound and an iminoindolyl group are added to a reactor in a molar ratio of 1:3, chloroform is added as a solvent, and pyridine is added as a catalyst. The mixture is stirred with a magnetic stirring device to dissolve it. The reaction is carried out at room temperature for 3 hours. After the reaction is completed, the solvent is evaporated under reduced pressure at no more than 50°C to obtain a crude product, which is purified by column chromatography to obtain the target compound.

[0009] The structure is Formula I

[0010]

[0011] Wherein Ar = N,N-dimethylaniline and its derivatives, which can be any one of the following groups.

[0012]

[0013] Beneficial effects of the present invention:

[0014] 1. The present invention synthesizes a new organic molecular stimulus-responsive material system with AIE performance, which exhibits a series of changes in the absorption spectrum after stimulation with light and acid as the starting factors.

[0015] 2. The organic molecular stimulus-responsive material provided by the present invention is superior to other stimulus-responsive materials in terms of operation width, response significance, and multi-mode response.

[0016] 3. The organic molecule stimulus response with AIE property provided by the present invention has few synthesis steps, simple method and readily available raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A, B are the normalized absorption spectra of PIO-01 and PIO-02 in THF, respectively.

[0018] Figure 2 A, B are the emission spectra of the obtained materials PIO-01 and PIO-02 at 298 K and 77 K, respectively.

[0019] Figure 3 A and B are the changes in the absorption spectra of PIO-01 and PIO-02 after adding acid.

[0020] Figure 4 A is the fluorescence spectra under different water content conditions at room temperature. After gradually adding water to the THF solution, the fluorescence intensity of PIO-01 and PIO-02 increased significantly. Figure 4 B is I / I of PIO-01 0 Plotted against the water content of the solvent mixture.

[0021] Figure 5 This is the Z / E heterogeneous structure diagram of PIO-01.

[0022] Figure 6 This is the mass spectrum of PIO-01.

[0023] Figure 7 This is the mass spectrum of PIO-02. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0025] Embodiment 1:

[0026] Preparation of photosensitizer PIO-01:

[0027]

[0028] Synthesis route of PIO-01

[0029] Synthesis of 4-nitro-N,N-diphenylaniline (3): Compound 1 (2.00 g) and potassium carbonate were added to a double-necked flask containing 20.00 mL DMSO at room temperature. After stirring for 10 min, compound 2 (2.00 g) was added. o C for 7 h. Thereafter, the mixture was cooled to room temperature, poured into ice water (60.00 mL), and extracted three times with dichloromethane. The crude product was further purified by recrystallization from petroleum ether to obtain a yellow solid (3.19 g, 93.02%).

[0030] Synthesis of N,N-diphenylbenzene-1,4-diamine (4): Compound 3 (2.00 g) and stannous chloride (5.20 g) were dissolved in 40.00 mL of ethanol, placed in a two-necked round-bottom flask, and 20.00 mL of concentrated hydrochloric acid was added to react at room temperature. o The mixture was stirred at 40 °C for 5 h. The reaction was quenched with water and the solvent was removed by evaporation under reduced pressure. The solution was concentrated under reduced pressure to obtain a pink solid (1.72 g, 96.01%).

[0031] Synthesis of 4-nitroso-N,N-diphenylaniline (5): Compound 4 (3.00 g) was dissolved in DCM (35.00 mL) at 0 °C. Before heating to room temperature, 7.08 g of persulfate (OXONE) (1.52 mmol, dissolved in 35.00 mL of deionized water) was added dropwise. The mixture was stirred for 30 min and extracted three times with DCM (30.00 mL). The organic layer was washed with anhydrous MgSO 4 The crude product was concentrated in vacuo and then quickly purified by PE:DCM column chromatography to obtain an orange-yellow solid, which was directly used for the reaction with compound 6 due to its instability.

[0032] Synthesis of PIO-01: Compound 5 (35.62 mg, 0.13 mmol) and compound 6 (22.00 mg) were dissolved in 5.00 mL of dry chloroform under a nitrogen atmosphere. Then, two drops of piperidine were added to the reaction mixture and stirred for 1 h. Subsequently, the mixture was poured into water and extracted with ethyl acetate. The crude product was concentrated under reduced pressure and purified by PE:DCM column chromatography. The target product PIO-01 was obtained as a purple crystalline solid (82 mg, 40.32%).

[0033] The structural characterization data of the obtained product are shown below:

[0034] 1H NMR (500 MHz, CDCl 3) δ 8.66 (d, J = 8.4 Hz, 1H), 7.74–7.65 (m,2H), 7.29 (d, J=8.3Hz 3H), 7.26–7.24 (m, 2H), 7.16 (d, J = 7.6 Hz, 4H), 7.08(d, J=8.6 Hz, 4H), 7.05–6.98 (m, 4H), 2.87 (s, 3H). ESI-MS (ESI + ): calc.(C 28 H 21 N 3 O 2 + ): 431.16, found: 431.16 (M).

[0035] Embodiment 2:

[0036] Preparation of photosensitizer PIO-02

[0037] The synthetic route is as follows:

[0038]

[0039] Synthesis route of PIO-02

[0040] Synthesis of N-(4-nitrophenyl)-N-phenylnaphthalen-1-amine (8): The process was similar to compound 3. Compound 1 was replaced by compound 7 (2.00 g). The crude product was further purified by PE recrystallization to obtain a yellow solid (3.23 g, 90.02%).

[0041] N 1 -(1-naphthyl)-N 1 Synthesis of -phenylbenzene-1,4-diamine (9): The synthesis method is the same as compound 4. Compound 3 is replaced by compound 8 (1.00 g). The crude product is further purified by PE recrystallization to obtain a white solid (0.98 g, 78.34%).

[0042] Synthesis of N-(4-nitrosophenyl)-N-phenylnaphthalen-1-amine (10): The synthesis method is the same as compound 5. Compound 4 is replaced by compound 9 (1.00 g). The crude product is quickly purified by PE:DCM (3:1, v:v) column chromatography to obtain an orange-yellow solid, which is directly used for the reaction with compound 6 due to its instability.

[0043] Synthesis of PIO-02: The synthesis method is the same as that of PIO-01. Compound 5 is replaced by compound 10. The target product PIO-02 is obtained as a purple crystalline solid (80 mg, 40.00%).

[0044] The structural characterization data of the obtained product are shown below:

[0045] 1 H NMR (500 MHz, DMSO-d 6 ) δ 8.40 (d, J = 8.3 Hz, 1H), 8.02 (d, J = 8.2Hz, 1H), 7.91 (dd, J = 8.7, 3.6 Hz, 2H), 7.78 (t, J = 7.9 Hz, 1H), 7.68 (d, J= 7.5 Hz, 1H), 7.60 (t, J = 7.8 Hz, 1H), 7.54 (t, J = 7.5 Hz, 1H), 7.47 (t, J= 7.7 Hz, 1H), 7.40 (d, J = 7.3 Hz, 1H), 7.34 (t, J = 7.5 Hz, 1H), 7.24 (t, J= 7.8 Hz, 2H), 7.04 (d, J = 8.3 Hz, 2H), 6.94–6.90 (m, 4H), 2.63 (s, 3H).ESI-MS (ESI + ): calc. (C 32 H 23 N 3 O 2 + ): 481.17, found: 504.16 (MNa + ).

[0046] Embodiment 3:

[0047] Absorption spectroscopy characterization of DA-type organic molecular stimuli-responsive materials (PIO-01 and PIO-02)

[0048] Figure 1 A and Figure 1 B is the absorption spectra of materials PIO-01 and PIO-02 obtained in Examples 1 and 2 in THF. The maximum absorption spectrum of PIO-01 in THF solution is 573 nm, while the maximum absorption wavelength of PIO-02 is 571 nm.

[0049] Embodiment 4:

[0050] Emission spectra characterization of DA-type photosensitizers (PIO-01 and PIO-02)

[0051] Figure 2The emission spectra of materials PIO-01 and PIO-02 obtained in Examples 1 and 2 in THF at 298 K and 77 K are shown. The emission peak spectrum of PIO-01 is a double-peak emission. This is because the donor has different emissions at different angles. It can be seen that the emission at 77 K is greatly enhanced compared with 298 K under low-temperature suppression of non-radiative transitions. The low-temperature emission of PIO-01 is at 730 nm and 1000 nm. PIO-02 basically exhibits the same properties as PIO-01.

[0052] Embodiment 5:

[0053] Changes in the absorption spectra of PIO-01 and PIO-02 after adding acid

[0054] Figure 3 A is the change in the absorption wavelength of PIO-01 after adding trifluoroacetic acid. It has red-shifted from 573 nm to 728 nm and has entered the absorption range of the second near-infrared region. The theoretically calculated electron spin density map and electrostatic formula map show that the obvious change in the data after adding trifluoroacetic acid is near its C=N double bond, indicating that it contributes to the red shift or fading after protonation. It is precisely because of this obvious color controllable change that it lays a solid foundation for its application in acid decryption information encryption. Figure 3 B is the change in the absorption wavelength of PIO-02 after adding trifluoroacetic acid, which red-shifts from 571 nm to 718 nm and has the same properties as PIO-01.

[0055] Embodiment 6:

[0056] Figure 4 A is the fluorescence spectrum under different water content conditions. After gradually adding water to the THF solution, the fluorescence intensity of PIO-01 increased significantly. Figure 4 B is I / I of PIO-01 0 The fluorescence intensity increases with the addition of water, indicating its aggregation-induced emission characteristics.

[0057] Embodiment 7:

[0058] When PIO-01 is excited by visible light, it exists within picoseconds. Figure 5 A and B show two isomeric shapes.

Claims

1. A type of DA type organic molecular stimulus responsive material, whose molecular characteristics are: , where Ar = N,N-dimethylaniline and its derivatives, which can be any one of the following groups, .

2. The DA type organic molecular stimulus responsive material according to claim 1, characterized in that: The connection of C=N double bonds makes the molecule have the characteristics of common azobenzene molecules. The introduction of donor acceptors makes its absorption wavelength fall into the near-infrared absorption range and has relaxation changes in picoseconds. These characteristics give it potential properties of near-infrared excitation, biomedical applications, optical signal transmission and other advantages.

3. The DA type organic molecular stimulus responsive material according to claim 1, characterized in that: At room temperature, in the solution of tetrahydrofuran and water, as the water content increases, the molecules aggregate and inhibit their non-radiative transitions, showing the phenomenon of emission enhancement, thus realizing the AIE characteristic; after lowering the temperature to 77 K to suppress their non-radiative transitions as much as possible, their emission intensity is greatly enhanced, and the emission wavelength is in the emission range of the second near-infrared region, which provides a prerequisite for fluorescence imaging and fluorescence positioning that require working in a relatively low temperature environment.

4. The DA type organic molecular stimulus responsive material according to claim 1, characterized in that: Due to the presence of the C=N double bond, when a trifluoroacetic acid proton-donating agent is added, it acts on the C=N double bond to promote the aggregation of electron spins near the double bond, thereby causing red shift or fading after protonation. After the DA-type organic molecule is mixed with a tetrahydrofuran solution of PMMA (polymethyl methacrylate), it is drop-coated on a glass substrate to prepare a thin film, and its excellent properties are still retained. Due to its wide color change dimension and obvious color change, the material of the present invention has good application prospects in information storage, information encryption, and information confidentiality.

5. The DA type organic molecular stimulus responsive material according to claim 1, characterized in that: Based on triphenylamine and its derivatives, a strong charge transfer state between donors and acceptors is used to achieve a red shift in the absorption wavelength, thereby obtaining near-infrared absorbing materials and enriching the semi-thioindigo derivative molecular motor system.

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