Intrinsic dipole moment-driven asymmetric luminescent Cichiabin double-free-radical compound and preparation and application of intrinsic dipole moment-driven asymmetric luminescent Cichiabin double-free-radical compound

Abstract

The invention belongs to the field of organic photoelectric materials, and particularly discloses an asymmetric biradical molecule, the structure of which is # imgabs0 #, and preparation and application of the compound. The dipole moment-driven asymmetric double-free-radical molecule disclosed by the invention is high in stability, and the asymmetric double-free-radical conjugated molecule has an intrinsic luminescence property of a near-infrared second region (single-molecule luminescence in a non-polar solvent reflects intrinsic luminescence). The intrinsic dipole moment not only can regulate and control the contribution of double free radicals (the dipole moment is increased to a certain degree, the index of the double free radicals is reduced, which indicates that charge separation and the double free radicals have a competitive relationship), but also influences the luminescent property of a near-infrared second region, and further can reveal an important association rule of dipole moment-free radical contribution value-luminescent property; the invention discloses a general phenomenon that a molecular material emits light in a near-infrared second region by increasing the dipole moment of double free radicals, i.e., the index level of the luminous efficiency is reduced due to the red shift of the luminous wavelength.

Description

Technical Field

[0001] The invention relates to the field of functional molecular materials, in particular to a class of organic functional materials of asymmetric biradical molecules. Background Art

[0002] Functionalized organic π-conjugated systems can achieve control of electronic structure and electronic motion within organic molecular regions and regulation of molecular aggregation states, and have unique photoelectric response properties and easy processing characteristics. In the past two decades, organic π-conjugated molecular materials have developed rapidly in the fields of light-emitting diodes, field-effect transistors, solar cells, chemical sensors, bio-imaging, capacitors, conductive coatings, etc. With the continuous development of various high-tech technologies, the functions and requirements of materials are increasing, and the development and research of new materials are becoming increasingly urgent.

[0003] Organic diradicals are a class of organic π molecules with two unpaired electrons and an open-shell ground state electronic structure. Open-shell polycyclic aromatic hydrocarbons are crucial to the understanding of the nature of chemical bonds and the physical and chemical phenomena of π-conjugated systems. For diradical organic conjugated systems, quinone structures are often used as building blocks of free radicals. p-quinodimethane (p-QDM) and o-quinodimethane (o-QDM), Thiele's hydrocarbons, and Chichibabin's hydrocarbons are widely used ( Figure 1 ). The conversion between its high and low spin states opens the door to organic magnetic compounds, which makes it have broad application prospects in the fields of spin electronic devices such as response characteristic materials, spin filters and information storage. Among its many unique physical and chemical properties, organic free radical materials with luminescent properties have attracted widespread attention in the academic community in recent years. Among them, the most typical luminophores are triarylmethyl monoradicals and their derivatives, which have been widely studied and paid attention to due to their certain stability and modifiability. Although free radical luminophores have made important progress, their research is still in a very early stage and still faces a series of problems that need to be solved: 1) Asymmetric biradicals have poor stability (locally distributed electrons or charges can easily lead to poor chemical stability); 2) There are few types of asymmetric biradicals, which are attributed to the difficulty in designing and constructing, and the preparation process is cumbersome; 3) Dipole moment induces charge separation, which can balance the contribution of free radicals in the electronic structure (the law revealed by a few DA-type free radical systems), but the influence of this balance relationship on photophysical properties, such as luminescence behavior, has rarely been reported in the literature so far.

[0004]

[0005] In recent years, near-infrared second region (NIR-II, 1000-1700nm) fluorescence imaging technology has become a popular imaging technology for basic research and clinical applications, with great application potential in the biomedical field. Due to reduced scattering, minimal absorption and negligible autofluorescence, it provides high signal-to-noise ratio and high spatial and temporal resolution for deep tissue imaging. Fluorescence imaging technology is an effective tool for preclinical or clinical applications, including disease diagnosis and visualization of drug targeting. Unlike various non-invasive imaging techniques, fluorescence imaging does not involve the use of harmful radiation, and it can provide wide-field images with high signal-to-noise ratio and excellent spatial and temporal resolution for medical diagnosis and pathological analysis. Although fluorescence imaging technology has made important progress, its research is still in a very early stage and still faces a series of problems that need to be solved. Most fluorophores emit wavelengths around 1000nm, making imaging in the NIR-II region difficult. Summary of the invention

[0006] In order to solve the problems of the prior art, the present invention provides a class of asymmetric luminescent Chichibabin diradical compounds driven by intrinsic dipole moment, aiming to obtain new compounds with intrinsic luminescent properties in the second near-infrared region.

[0007] The second object of the present invention is to provide the preparation of the asymmetric luminescent Chichibabin diradical compound driven by the intrinsic dipole moment and its application in organic luminescent materials.

[0008] The third object of the present invention is to provide an organic photoelectric material comprising the asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment.

[0009] The asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment has a structure of formula 1:

[0010]

[0011] In Formula 1, R1, R2, R3, and R4 are independently H, -Cl, -Br, -I, -CN, -CF3, C1-C 24 Alkyl, C3-C 24 Cycloalkyl, C1-C 24 Alkoxy, C1-C 24 Alkyl substituted aryl, halogenated C1-C 24 Alkyl, halogenated C3-C 24 Cycloalkyl or halogenated C1-C 24 Alkoxy;

[0012] The Z is O, S, B-Mes, N-CH3, O=Se=O, P-Ph or O=P-Ph;

[0013] The Ar is an aryl group or a substituted aryl group.

[0014] The present invention provides an asymmetric diradical compound of formula 1, which can realize intrinsic luminescence in the second near-infrared region based on intrinsic dipole moment driving, and not only that, it also has excellent stability and luminescence efficiency.

[0015] The luminescent material described in Formula 1 of the present invention that can be driven by intrinsic dipole moment has the following advantages: 1) the asymmetric diradical molecules driven by dipole moment have high stability; 2) the asymmetric diradical conjugated molecules have intrinsic luminescence properties in the second near-infrared region (single molecule luminescence in non-polar solvents reflects intrinsic luminescence); 3) the intrinsic dipole moment can not only regulate the contribution of diradicals (when the dipole moment increases to a certain extent, the diradical index decreases, indicating that there is a competitive relationship between charge separation and diradicals), but also affect the luminescence properties in the second near-infrared region, and further reveal the important correlation between dipole moment-radical contribution value-luminescence properties; 4) increasing the dipole moment of diradicals can inhibit the common phenomenon of molecular materials emitting light in the second near-infrared region, that is, the red shift of the luminescence wavelength leads to an exponential decrease in luminescence efficiency (limited by the energy gap law).

[0016] The asymmetric biradical molecules described in the present invention can change the strength of the dipole moment through the side chain to regulate the absorption and emission wavelengths and luminous efficiency of the material, so that they show excellent application prospects in the field of organic optoelectronic materials.

[0017] In the present invention, R1 is H, -Cl, -Br, -I, -CN, -CF3, and more preferably -CF3.

[0018] The R2 is H, C1-C 24 Alkyl, C3-C 24 Cycloalkyl, C1-C 24 Alkoxy, C1-C 24 Alkyl substituted aryl, halogenated C1-C 24 Alkyl, halogenated C3-C 24 Cycloalkyl or halogenated C1-C 24 The alkoxy group is more preferably H.

[0019] The R3 is H, -Cl, -Br, -I, -CN, -CF3, -NO2, -ArC1, -C 24 Alkyl substituted aryl, halogenated C1-C 24 Alkyl, halogenated C3-C 24 The cycloalkyl group is more preferably H.

[0020] The R4 is H, -Cl, -Br, -I, -CN, -CF3, -NO2, -Ar, and is more preferably -CF3.

[0021] The Z is O.

[0022] In the Ar, the aromatic group includes a benzene ring, a five-membered aromatic heterocycle, a six-membered aromatic heterocycle or a condensed ring; the substituted aromatic group is a group having at least one substituent selected from the group consisting of an alkyl group, an alkoxy group, a trifluoromethyl group, an acyl group, an ester group, a nitro group and a halogen group on the aromatic ring.

[0023] Preferably, Ar is More preferably

[0024] The asymmetric biradical molecules that can be cited in the present invention have structures of Formula 1-A, Formula 1-B and Formula 1-C:

[0025]

[0026] The present invention also provides a method for preparing the intrinsic dipole moment driven asymmetric luminescent Chichibabin diradical compound, which comprises subjecting the raw material of formula 2, a base and an oxidant to dehydrogenation and oxidation to obtain;

[0027]

[0028] In the present invention, the dehydrogenation and oxidation may be conventional, for example:

[0029] In the present invention, the base includes an alkali metal alcoholate, for example, potassium tert-butoxide.

[0030] The oxidant may be a quinone compound, and may further be chlorobenzoquinone.

[0031] In the deoxidation and hydrogenation process of the present invention, the addition equivalent of the alkali is 1 to 5 Eqv, and can be further 2 to 4 Eqv in consideration of the cost, and the addition equivalent of the oxidant is 1 to 2 Eqv.

[0032] The dehydrogenation reaction is carried out under anaerobic conditions.

[0033] The solvent for the dehydrogenation reaction is, for example, one of THF, Toluene, and DCM; more preferably THF;

[0034] The reaction time of dehydrogenation oxidation is 6-12h.

[0035] In the present invention, after the dehydrogenation and oxidation, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain an oxidation product.

[0036] In the present invention, the formula 2 is obtained by oxidation through the formula 3;

[0037]

[0038] In the present invention, the oxidation step may be conventional, for example:

[0039] Preferably, the oxidizing agent added in the oxidation reaction stage includes at least one of meta-chloroperbenzoic acid, aluminum chloride, ferric chloride, scandium trifluoromethanesulfonate, and DDQ.

[0040] Preferably, the dosage equivalent of the oxidizing agent in the oxidation reaction stage is 1 to 5 Eqv, and can be further 2 to 4 Eqv in consideration of the cost.

[0041] Furthermore, the oxidation reaction solvent may be one of THF, Toluene, and DCM; more preferably DCM.

[0042] In the present invention, after the oxidation reaction, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain an oxidation reaction product.

[0043] Formula 3 is prepared by mixing Formula 4 with ArH and a Friedel-Crafts reaction catalyst to perform Friedel-Crafts reaction;

[0044]

[0045] In the present invention, the Friedel-Crafts reaction steps and conditions can be adjusted based on known principles, for example:

[0046] The Friedel-Crafts reaction catalyst may be a conventional Lewis acid catalyst, for example, may include at least one of ferric chloride hexahydrate, boron trifluoride etherate, gold trichloride, and zinc dichloride.

[0047] The dosage equivalent of the Friedel-Crafts reaction catalyst can be 0.1 to 0.3 Eqv.

[0048] The temperature of the Friedel-Crafts reaction is 80°C or higher, and may be 90 to 150°C.

[0049] The Friedel-Crafts reaction also allows the addition of anhydride, the amount of which can be, for example, 5 to 10 eqv.

[0050] In the present invention, the formula 4 is obtained by Suzuki coupling reaction of formula 5 and formula 6

[0051]

[0052] In the present invention, the steps and conditions of the Suzuki coupling reaction can be adjusted based on known principles, for example:

[0053] The catalyst for the Suzuki coupling reaction is at least one of Pd(dppf)Cl2, Pd(PPh3)2Cl2, and Pd(PPh3)4. The amount thereof can be, for example, 0.01 to 0.05 eqv.

[0054] The Suzuki coupling reaction stage also allows the addition of a base, such as at least one of sodium carbonate and potassium carbonate, and the amount thereof can be, for example, 1 to 3 eqv.

[0055] Suzuki coupling was performed in the absence of oxygen.

[0056] The molar ratio of Formula 5 to Formula 6 may be 1:1-2.

[0057] The reaction temperature of the Suzuki coupling is preferably 90°C to 100°C.

[0058] The solvent for Suzuki coupling is at least one of DME, H2O, THF, Dioxane and Toluene; more preferably DME and H2O, wherein the volume ratio of DME to H2O is 3:1.

[0059] In the present invention, after Suzuki coupling, an organic solvent can be used for extraction, and the collected organic phase can be concentrated and chromatographically separated to obtain Suzuki coupling.

[0060] The formula 5 is obtained by the Miyaura boronation reaction of the formula 7 with a biboronic acid pinacol compound.

[0061]

[0062] In the present invention, the steps and conditions of the Miyaura borylation reaction can be adjusted based on known principles, for example:

[0063] The catalyst for the Miyaura borylation reaction is Pd(dppf)Cl2, and its usage is, for example, 0.01 to 0.03 eqv.

[0064] The Miyaura borylation reaction stage also allows the addition of carboxylate, such as potassium acetate, in an amount of, for example, 1 to 3 eqv.

[0065] The Miyaura borylation reaction is carried out in the absence of oxygen.

[0066] The reaction temperature of the Miyaura borylation reaction is preferably 90°C to 100°C.

[0067] The solvent for the Miyaura borylation reaction is at least one of Dioxane, THF, Et3N, and DCM; Dioxane is more preferred.

[0068] In the present invention, after the Miyaura borylation reaction, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain a Miyaura borylation product.

[0069] The invention also provides an application of the asymmetric luminescent Chichibabin diradical compound driven by the intrinsic dipole moment, which is used for preparing organic photoelectric materials.

[0070] Preferably, it is used to prepare near-infrared second-zone organic optoelectronic material.

[0071] Preferably, the organic photoelectric material is at least one of a biological imaging material, a semiconductor electronic device, an energy storage material, and a spin material.

[0072] The present invention also provides an organic photoelectric material, which comprises the asymmetric luminescent Chichibabin diradical compound driven by the intrinsic dipole moment or is prepared by the same.

[0073] Beneficial Effects

[0074] The present invention discloses a method for regulating the size of dipole moment by using side chain groups to promote charge transfer within the molecule, which is also expected to achieve the regulation of absorption and emission wavelength and luminous efficiency of materials, and provides a class of asymmetric biradical molecules, design, synthesis and application. The advantages of the invention are: 1) the asymmetric biradical molecules driven by dipole moment are highly stable; 2) the asymmetric biradical conjugated molecules have intrinsic luminescence properties in the second near-infrared region (single molecule luminescence in non-polar solvents reflects intrinsic luminescence); 3) the intrinsic dipole moment can not only regulate the contribution of biradicals (when the dipole moment increases to a certain extent, the biradical index decreases, indicating that there is a competitive relationship between charge separation and biradicals), but also affect the luminescence properties in the second near-infrared region, and further reveal the important correlation between dipole moment-radical contribution value-luminescence properties; 4) increasing the dipole moment of biradicals can inhibit the common phenomenon of molecular materials emitting light in the second near-infrared region, that is, the red shift of the luminescence wavelength leads to an exponential decrease in luminescence efficiency (limited by the energy gap law). BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 This is the mass spectrum of the DD-1 compound prepared in Example 1.

[0076] Figure 2 This is the mass spectrum of the DD-2 compound prepared in Example 1.

[0077] Figure 3 This is the mass spectrum of the DD-3 compound prepared in Example 1.

[0078] Figure 4 This is the low temperature NMR (-80°C) of the DD-1 compound prepared in Example 1.

[0079] Figure 5 This is the low temperature NMR (-80°C) of the DD-2 compound prepared in Example 1.

[0080] Figure 6 This is the low temperature NMR (-80°C) of the DD-3 compound prepared in Example 1.

[0081] Figure 7 This is the variable temperature NMR of the DD-1 compound obtained in Example 1.

[0082] Figure 8 This is the variable temperature NMR of the DD-2 compound obtained in Example 1.

[0083] Fig. 9 This is the variable temperature NMR of the DD-3 compound obtained in Example 1.

[0084] Fig.10 It is the temperature-dependent ESR of compounds DD-1, DD-2, and DD-3 obtained in Example 1.

[0085] Fig.11 The UV-visible absorption spectrum, fluorescence spectrum and cyclic voltammetry curve of the solid solution of DD-1, DD-2 and DD-3 compounds prepared in Example 1 are shown.

[0086] Fig.12 It is the UV-visible spectral solvent effect of compounds DD-1, DD-2, and DD-3 prepared in Example 1 (DCM is dichloromethane, THF is tetrahydrofuran, Tol is toluene, PhCl is chlorobenzene, and Cy is cyclohexane).

[0087] Fig.13 This is the single crystal structure of the SD compound prepared in Example 1.

[0088] Fig.14 This is the single crystal structure of the DD-1 compound obtained in Example 1.

[0089] Fig.15 This is the single crystal structure of the DD-2 compound obtained in Example 1.

[0090] Fig.16 This is the single crystal structure of the DD-3 compound obtained in Example 1.

[0091] Fig.17 It is the application of the DD-1 to 3 compounds prepared in Example 1 - fluorescence imaging; DETAILED DESCRIPTION

[0092] The present invention provides an optional method for preparing an asymmetric biradical molecule and its derivatives, comprising the following steps:

[0093] Step (1):

[0094] The compound of formula a undergoes Miyaura borylation reaction with a biboronic acid pinacol compound to obtain a compound of formula b

[0095] Step (2):

[0096] The compound of formula b undergoes Suzuki coupling with the compound of formula c to obtain the compound of formula d

[0097] Step (3):

[0098] The compound of formula d undergoes Friedel-Crafts reaction to obtain the compound of formula e

[0099] Step (4):

[0100] The compound of formula e undergoes oxidation reaction to obtain a compound of formula f

[0101] Step (5):

[0102] The compound of formula f undergoes oxidation reaction to obtain a compound of formula g

[0103]

[0104]

[0105] In step (1), R1, R4, R2, and R3 are hydrogen or trifluoromethyl, and Z is O; and the catalyst is at least one of PdCl2-dppf and Pd(PPh3)2Cl2.

[0106] In step (2), the catalyst is at least one of PdCl2-dppf, Pd(PPh3)2Cl2, and Pd(PPh3)4.

[0107] In step (3), the reaction is carried out in the presence of ferric chloride hexahydrate and acetic anhydride;

[0108] The oxidizing agent in step (4) is at least one of m-chloroperbenzoic acid and H2O2.

[0109] In step (5), the oxidation reaction is carried out in the presence of a base and an oxidant; the base and the oxidant are potassium tert-butoxide and tetrachlorobenzoquinone, respectively.

[0110] Used in biological imaging, semiconductor electronic devices, energy storage, spin materials, etc.

[0111] R2 and R3 are hydrogen, R1 and R4 are trifluoromethyl, Z is O, and the final product is an asymmetric biradical molecule.

[0112] In step (1), R1, R4, R2, and R3 are hydrogen or trifluoromethyl, Z is O or N-CH3, and the catalyst is at least one of Pd(dppf)Cl2 and Pd(PPh3)2Cl2.

[0113] R1 and R4 are trifluoromethyl, R2 and R3 are hydrogen, and Z is O;

[0114] The catalyst is Pd(dppf)Cl2;

[0115] The Miyaura borylation reaction is carried out in the absence of oxygen;

[0116] The reaction temperature of the Miyaura borylation reaction is preferably 90°C to 100°C;

[0117] The solvent of the Miyaura borylation reaction is at least one of Dioxane, THF, Et3N, and DCM; more preferably Dioxane;

[0118] In the present invention, after the Miyaura borylation reaction, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain a Miyaura borylation product.

[0119] In step (2), the catalyst is at least one of Pd(dppf)Cl2, Pd(PPh3)2Cl2, and Pd(PPh3)4.

[0120] The catalyst is Pd(PPh3)4;

[0121] Suzuki coupling was performed in the absence of oxygen;

[0122] The reaction temperature of the Suzuki coupling is preferably 90°C to 100°C;

[0123] The solvent for Suzuki coupling is at least one of DME, H2O, THF, Dioxane and Toluene; more preferably DME and H2O, wherein the volume ratio of DME to H2O is 3:1;

[0124] In the present invention, after Suzuki coupling, an organic solvent can be used for extraction, and the collected organic phase can be concentrated and chromatographically separated to obtain Suzuki coupling.

[0125] In step (3), the reaction is carried out in the presence of ferric chloride hexahydrate and acetic anhydride;

[0126] The Friedel-Crafts reaction solvent is at least one of mesitylene, mesitylene triethylbenzene, trichlorobenzene, and mesitylene triisopropylbenzene; more preferably mesitylene;

[0127] The reaction temperature of the Friedel-Crafts reaction is preferably 100°C;

[0128] In the present invention, after the Friedel-Crafts reaction, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain a Friedel-Crafts reaction product.

[0129] In step (4), the oxidation reaction is carried out in the presence of an oxidant; the oxidant is at least one of meta-chloroperbenzoic acid and H2O2, and is more preferably meta-chloroperbenzoic acid;

[0130] The oxidation reaction solvent is at least one of THF, Toluene, and DCM; more preferably DCM;

[0131] In the present invention, after the oxidation reaction, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain an oxidation reaction product.

[0132] In step (5), the base and oxidizing agent used are potassium tert-butoxide and tetrachlorobenzoquinone;

[0133] The oxidation reaction takes place in the absence of oxygen;

[0134] The oxidation reaction solvent is at least one of THF, Toluene, and DCM; more preferably THF;

[0135] Under the coordination of the preferred reaction solvent system and the dosage of the oxidant, the preferred reaction time is 6-12 hours; more preferably 12 hours;

[0136] In the present invention, after the oxidation reaction, an organic solvent may be used for extraction, and the collected organic phase may be concentrated and chromatographically separated to obtain an oxidation product.

[0137] Embodiment 1:

[0138] The synthetic route is as follows:

[0139]

[0140] The specific steps of DD-1 are as follows (the steps of DD-2 and DD-3 are the same as those of DD-1):

[0141] (1) Under the protection of argon, compound 1 (1.00 g, 2.90 mmol), B2Pin2 (1.5 g, 5.80 mmol) and CH3COOK (426 mg, 4.34 mmol) were dissolved in 80 mL dioxane solvent, and the mixture was aerated for half an hour. Pd(dfft)Cl2 (42 mg, 0.06 mmol) was added, and the mixture was heated to 90°C and refluxed overnight. After the reaction was completed, the mixture was returned to room temperature, extracted with water (50 mL) and dichloromethane (100 mL), the organic phase was collected and dried with anhydrous magnesium sulfate, filtered and the solvent was removed under reduced pressure, and the crude product was purified by silica gel column chromatography (eluent: PE:EA = 30:1-10:1 gradient elution) to obtain solid compound 2.

[0142] (2) Under the protection of argon, compound 3 (1.00 g, 2.77 mmol) and compound 2 (1.2 g, 4.15 mmol) and K2CO3 (766 mg, 5.54 mmol) were dissolved in 100 ml of a mixture of DME and water (DME / H2O=3:1). After bubbling for half an hour, Pd(PPh3)4 (64 mg, 0.06 mmol) was added. The mixture was heated to 100°C and refluxed overnight. After the reaction was completed, the mixture was returned to room temperature, water (30 mL) was added and extracted with dichloromethane (3×10 mL). The organic phase was collected and dried with Na2SO4, filtered and spin-dried, and separated and purified on silica gel chromatography using PE:EA=20:1 as the eluent to obtain oily compound 4.

[0143] (3) Under the protection of argon, compound 4 (1 g, 1.8 mmol), acetic anhydride (1.5 g, 14.64 mmol), and FeCl3·6H2O (99 mg, 0.4 mmol) were dissolved in 30 mL of Mesitylene, heated to 110°C, and refluxed overnight. After the reaction was completed, the mixture was returned to room temperature and extracted with water (100 mL) and ethyl acetate (200 mL). The organic phase was collected and dried over anhydrous magnesium sulfate, filtered to remove the solvent, and separated and purified on silica gel chromatography (PE as the eluent) to obtain liquid compound 5.

[0144] (4) Compound 5 (200 mg, 0.27 mmol) was dissolved in dichloromethane (50 mL), and m-chloroperbenzoic acid (138 mg, 0.80 mmol) was added, and the mixture was reacted at room temperature for 2-3 hours. After the reaction was completed, the reaction solution was extracted with water (10 mL) and dichloromethane (20 mL), and the organic phase was collected and dried over anhydrous magnesium sulfate. After the solvent was removed by suction filtration, the mixture was purified by silica gel chromatography (PE / DCM=10:1) to obtain Compound 6.

[0145] (5) Compound 6 (100 mg, 0.13 mmol) was dissolved in anhydrous THF (50 mL), potassium tert-butoxide (43 mg, 0.39 mmol) was added, and the mixture was reacted at room temperature overnight. Chlorobenzoquinone (48 mg, 0.19 mmol) was then added. After the reaction was completed, the reaction solution was extracted with water (10 mL) and dichloromethane (20 mL). The organic phase was collected and dried over anhydrous magnesium sulfate. The solvent was removed by filtration, and then purified by silica gel chromatography (PE / THF=10:1) to obtain Compound 7.

[0146] Verification of properties of DD-1 to DD-3

[0147] The examples of the present invention confirmed the structures of DD-1 to DD-3 by means of variable temperature nuclear magnetic resonance hydrogen spectrum, mass spectrum, ultraviolet-visible-near infrared absorption spectrum, single crystal diffraction and the like, and studied their related properties.

[0148] Fig.11 The UV-visible-near infrared absorption spectra, fluorescence spectra and cyclic voltammetry curves of the dichloromethane solutions of compounds DD-1 to 3 and the related photophysical properties are shown in Table 1. Fig.11 In the embodiment, the structure of SD is a DD-2 compound in which Z is -SO2-, and its structure is:

[0149]

[0150] The results of electronic absorption spectrum show that the maximum absorption wavelength of compound DD-1 is 855nm, while the absorption bands of compounds DD-2 and DD-3 are red-shifted by about 48nm and 115nm, with maximum absorption wavelengths of 903nm and 970nm. The results of fluorescence spectrum show that the emission wavelengths of compounds DD-1 to DD-3 are 1023nm, 1074nm, 1180nm, and the Stokes shift is 179nm -1 ,186nm -1 , 210nm -1 The calculated fluorescence quantum yields (PLQY) of compounds DD-1 to DD-3 are 0.84%, 0.22% and 0.17%, respectively, indicating that the substituents of asymmetric diradical compounds that use side chain groups to regulate the size of the dipole moment play an important role in their radiation decay process.

[0151] Table 1 Photophysical properties of DD-1 to 3 in dichloromethane

[0152]

[0153] Figure 13-16The single crystal structure diagrams of SD, DD-1~3 are shown in Figure 1. The four compounds were dissolved in DCM, toluene, THF, and toluene solutions, and then vapor-diffused with n-hexane to obtain high-quality crystals. In asymmetric compounds, as the dipole moment increases, the molecules gradually change from planar to twisted to a dihedral angle of 15°, and the twist angle of the two benzene rings of tschibabin in DD-2 is 14.9°, while the other three are parallel. By calculating its aromaticity, it is found that the benzene rings on the tschibabin skeleton are all aromatic, which indicates that these four molecules may have the properties of diradicals. Therefore, we calculated that these molecules all have a large diradical index (70~79%), and interestingly, as the dipole moment increases, the diradical index slowly decreases, which indicates that the intrinsic dipole moment can regulate the contribution of diradicals, indicating that there is a competitive relationship between charge separation and diradicals.

[0154] Fig.16 The application of compound DD-1~3 - fluorescence imaging; a is the fluorescence image of DD-1~3 under 808nm light irradiation; c is the fluorescence image of mouse subcutaneous near-infrared zone II under 808nm excitation of DD-1~3 (10μg / mL) and d is the corresponding fluorescence intensity. Because the emission wavelength of the compound has reached the near-infrared zone II, it is well known that the scattering of near-infrared zone II luminescence in biological tissues is low, which can achieve deeper tissue penetration, which is particularly important for imaging of deep tissues or organs. Therefore, compound DD-1~3 was tested for fluorescent mouse light imaging. It can be seen from Figure d that compared with the blank control group, compound DD-1~3 has a stronger fluorescence intensity, which shows that DD-1~3 can be used for fluorescence imaging. At the same time, it also verifies the general phenomenon that increasing the dipole moment of the biradical can inhibit the luminescence of molecular materials in the near-infrared zone II, that is, the red shift of the luminescence wavelength leads to an exponential decrease in luminescence efficiency (limited by the energy gap law).

[0155] In summary, the asymmetric biradical molecules described in the present invention can change the strength of the dipole moment through the side chain to regulate the absorption and emission wavelengths and luminous efficiency of the material, making it show excellent application prospects in the field of organic optoelectronic materials.

Claims

1. An asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment, characterized in that: Having the structure of formula 1: In Formula 1, R1, R2, R3, and R4 are independently H, -Cl, -Br, -I, -CN, -CF3, C1-C 24 Alkyl, C3-C 24 Cycloalkyl, C1-C 24 Alkoxy, C1-C 24 Alkyl substituted aryl, halogenated C1-C 24 Alkyl, halogenated C3-C 24 Cycloalkyl or halogenated C1-C 24 Alkoxy; The Z is O, S, B-Mes, N-CH3, O=Se=O, P-Ph or O=P-Ph; The Ar is an aryl group or a substituted aryl group.

2. The asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment according to claim 1, characterized in that: The R1 is H, -Cl, -Br, -I, -CN or -CF3, more preferably -CF3; Preferably, said R2 is H, C1-C 24 Alkyl, C3-C 24 Cycloalkyl, C1-C 24 Alkoxy, C1-C 24 Alkyl substituted aryl, halogenated C1-C 24 Alkyl, halogenated C3-C 24 Cycloalkyl or halogenated C1-C 24 Alkoxy, more preferably H; Preferably, R3 is H, -Cl, -Br, -I, -CN, -CF3, -NO2, -ArCl, -C 24 Alkyl substituted aryl, halogenated C1-C 24 Alkyl, halogenated C3-C 24 Cycloalkyl, more preferably H; Preferably, R4 is H, -Cl, -Br, -I, -CN, -CF3, -NO2, -Ar, and more preferably -CF3.

3. The intrinsic dipole moment driven asymmetric luminescent Chichibabin diradical compound according to claim 1, characterized in that: The Z is O.

4. The asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment according to claim 1, characterized in that: In the Ar, the aromatic group includes a benzene ring, a five-membered aromatic heterocycle, a six-membered aromatic heterocycle or a condensed ring; the substituted aromatic group is a group having at least one substituent selected from the group consisting of an alkyl group, an alkoxy group, a trifluoromethyl group, an acyl group, an ester group, a nitro group and a halogen group on the aromatic ring; Preferably, Ar is More preferably 5. A method for preparing the asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment according to any one of claims 1 to 4, characterized in that: The raw material of formula 2 and the oxidant are subjected to deoxidation and oxidation to obtain; Formula 2; Preferably, the base comprises an alkali metal alcoholate; Preferably, the oxidant is a quinone compound; Preferably, in the deoxidation and hydrogenation process, the addition equivalent of the base is 1 to 5 Eqv, and the addition equivalent of the oxidant is 1 to 2 Eqv; Preferably, the dehydrogenation reaction is carried out under anaerobic conditions; Preferably, the dehydrogenation reaction solvent includes one of THF, Toluene, and DCM; The reaction time of dehydrogenation is 6-12h.

6. The method for preparing the asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment as claimed in claim 5, characterized in that: The formula 2 is obtained by oxidation through formula 3; Preferably, the oxidizing agent added in the oxidation reaction stage includes at least one of meta-chloroperbenzoic acid, aluminum chloride, ferric chloride, scandium trifluoromethanesulfonate, and DDQ; Preferably, the dosage equivalent of the oxidizing agent in the oxidation reaction stage is 1 to 5 Eqv; Preferably, the oxidation reaction solvent is one of THF, Toluene and DCM.

7. The method for preparing the asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment as claimed in claim 6, characterized in that: Formula 3 is prepared by mixing Formula 4 with ArH and a Friedel-Crafts reaction catalyst to perform Friedel-Crafts reaction; Preferably, the Friedel-Crafts reaction catalyst comprises at least one of ferric chloride hexahydrate, boron trifluoride etherate, gold trichloride, and zinc dichloride; Preferably, the dosage equivalent of the Friedel-Crafts reaction catalyst can be 0.1 to 0.3 Eqv; Preferably, the temperature of the Friedel-Crafts reaction is above 80°C, and may further be 90-150°C.

8. The method for preparing the asymmetric luminescent Chichibabin diradical compound driven by intrinsic dipole moment as claimed in claim 7, characterized in that: Formula 4 is obtained by Suzuki coupling reaction of Formula 5 and Formula 6. Preferably, the catalyst for the Suzuki coupling reaction is at least one of Pd(dppf)Cl2, Pd(PPh3)2Cl2, and Pd(PPh3)4; Preferably, the reaction temperature of the Suzuki coupling is preferably 90°C to 100°C; Preferably, the formula 5 is obtained by a Miyaura borylation reaction of the formula 7 with a biboronic acid pinacol compound; Preferably, the catalyst for the Miyaura borylation reaction is Pd(dppf)Cl2; Preferably, the Miyaura borylation reaction is carried out in the absence of oxygen; Preferably, the reaction temperature of the Miyaura borylation reaction is preferably 90°C to 100°C; Preferably, the solvent for the Miyaura borylation reaction is at least one of Dioxane, THF, Et3N, and DCM; more preferably Dioxane.

9. Use of the intrinsic dipole moment driven asymmetric luminescent Chichibabin diradical compound according to any one of claims 1 to 4, characterized in that: Use it to prepare organic optoelectronic materials; Preferably, it is used to prepare near-infrared second-zone organic photoelectric material; Preferably, the organic photoelectric material is at least one of a biological imaging material, a semiconductor electronic device, an energy storage material, and a spin material.

10. An organic photoelectric material, characterized in that: The invention comprises the asymmetric luminescent Chichibabin diradical compound driven by the intrinsic dipole moment as described in any one of claims 1 to 4 or is prepared by the same.

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