A luminescent compound containing 9,9 coupled carbazole and its preparation method

Abstract

The present invention provides a luminescent compound containing a 9,9-coupled carbazole, whose Chinese name is 3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole. The present invention also provides a method for preparing the luminescent compound containing a 9,9-coupled carbazole, by preparing an intermediate product, 9,9-coupled-1,1'-3,6-di-tert-butylcarbazole, and then preparing the target product. The target product obtained exhibits multi-channel luminescent properties in both solution and solid states.

Description

Technical Field

[0001] The present invention relates to the field of fluorescent materials, and in particular to a luminescent compound containing 9,9-coupled carbazole and a preparation method thereof. Background Art

[0002] Single-molecule white-light organic luminescent materials have widespread applications in lighting, display, and detection. Generally speaking, single-molecule white light can be achieved by employing several common luminophores, including fluorescence, delayed fluorescence, and phosphorescence, in at least two complementary (blue / yellow, blue / orange, and green / pink) configurations. Currently, approaches to constructing single-molecule multi-channel luminescence are primarily limited to dual-channel systems. Key strategies include constructing single-molecule dual-excited-state luminescence, such as materials with TICT properties that can achieve dual luminescence in both LE and CT states. Other approaches involve generating additional luminescence channels through intermolecular interactions in the aggregated state to form exciplexes or excimer complexes, thereby achieving simultaneous luminescence in both single and aggregated states. Alternatively, single-molecule material compartments can generate thermoluminescence through heavy atom effects or crystallization-induced warm phosphorescence, thereby generating dual luminescence of fluorescence and phosphorescence. However, achieving high-purity white light with dual channels requires precise control of the emission colors of both channels, which presents challenges. Multi-channel systems (≥3) can achieve white light by connecting the luminescent material coordinates across the white light region. Furthermore, ternary (or multi-element) luminescence approaches are more easily achievable for high-purity white light control. However, achieving multi-channel luminescence of a single molecule goes against the Kasha rule and poses great challenges, with few reported cases.

[0003] Researchers selected pyrene and triarylboron to construct a three-channel luminescent organic fluorescent material, which achieved LE state (corresponding to luminescence wavelength of 378nm), CT (corresponding to luminescence wavelength of 428nm), and TICT (corresponding to luminescence wavelength of 452nm) in solution (Chem. Commun. 2012, 48(24), 2970-2972). Another study selected the nitrile unit and tetraazatetracycle to construct a three-channel luminescent compound, and obtained three-channel luminescence from LE state (corresponding to luminescence wavelength of 352nm), active complex formed within the molecule (corresponding to luminescence wavelength of 429nm), and TICT state (corresponding to luminescence wavelength of 473nm) (J. Am. Chem. Soc. 1998, 120(7), 1474-1478). The above rare multi-channel luminescence is mainly concentrated in the short-wave blue light region, and fails to meet the requirements of multi-channel luminescence to construct single-molecule white light. Summary of the Invention

[0004] The object of the present invention is to provide a luminescent compound containing 9,9-coupled carbazole, which can construct a highly twisted fluorescent luminescent material, fully inhibit the ACQ effect, and ensure its efficient luminescence.

[0005] Another object of the present invention is to provide a method for preparing a luminescent compound containing 9,9-coupled carbazole. The preparation method is simple, has few intermediate links, and the resulting compound has multi-channel luminescent properties in both solution and solid states.

[0006] This patent introduces a triphenyltriazine unit at the 1 or 1' position of the NN-coupled carbazole to construct a highly twisted fluorescent material, fully suppressing the ACQ effect and ensuring its efficient luminescence. The resulting compound exhibits LE-state luminescence of the coupled carbazole in solution, as well as CT-state luminescence generated by intramolecular charge transfer from the conjugated tert-butylcarbazole to the triazine unit, and CT-state luminescence generated by spatial charge transfer from the non-directly covalently linked tert-butylcarbazole to the triazine unit. Furthermore, the resulting compound exhibits multi-channel luminescence properties in both solution and solid states. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0008] Figure 1 This is a synthetic route diagram of Example Compound D of the present invention;

[0009] Figure 2 This is a fluorescence photograph of Example Compound D of the present invention in THF solution (excited by a handheld UV lamp at 365 nm);

[0010] Figure 3 The UV absorption spectra of Example D of the present invention in different solvents;

[0011] Figure 4 Graphs showing the excitation spectra of Example Compound D of the present invention at different wavelengths in THF solution. DETAILED DESCRIPTION

[0012] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0013] The following is a detailed description of a 9,9-coupled carbazole-containing luminescent compound and its preparation method according to an embodiment of the present invention.

[0014] The embodiment of the present invention provides a luminescent compound containing 9,9-coupled carbazole, which has the following structural formula:

[0015]

[0016] The Chinese name is 3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole.

[0017] The present invention also provides a method for preparing a luminescent compound containing 9,9-coupled carbazole, the method comprising the following steps:

[0018] S1, Preparation of 9.9-Bis-1,1'-3,6-di-tert-butylcarbazole:

[0019] 1-Bromo-3,6-di-tert-butylcarbazole was added to a two-necked flask and dissolved in acetone. KMnO4 was then added and the mixture was deoxygenated by nitrogen. The reaction system was heated to 60°C and refluxed under a nitrogen atmosphere. The mixture was cooled to room temperature and subjected to extraction, washing, and drying. The organic layer was collected by rotary evaporation and separated by silica gel column chromatography to obtain a yellowish-brown solid product, 9,9-bi-1,1'-3,6-di-tert-butylcarbazole.

[0020] Preparation of S2,3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole:

[0021] 9.9-bi-1,1'-3,6-di-tert-butylcarbazole, 2,4-diphenyl-6-[4-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolane-2-yl)phenyl]-1,3,5-triazine, Pd2(dba)3, 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, and TBAI were added to the two-necked flask in sequence, and the flask was sealed and nitrogen-filled and deoxygenated. TOL, which had been previously nitrogen-filled and deoxygenated, was injected into the flask using a long syringe. The K2CO3 solution was reacted at 100°C in a nitrogen atmosphere for 24 hours. After extraction, washing and drying, the organic layer was collected by rotary evaporation and separated by silica gel column chromatography to obtain a yellow solid product 3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole.

[0022] Furthermore, in a preferred embodiment of the present invention, in S1, the specific steps of extracting, washing and drying are extracting with DCM, washing with a saturated sodium thiosulfate solution, and drying with anhydrous magnesium sulfate.

[0023] Furthermore, in a preferred embodiment of the present invention, in S1, the reaction time is 6 hours.

[0024] Furthermore, in a preferred embodiment of the present invention, in S1, the yield of the yellow-brown solid product is 64.59%.

[0025] Furthermore, in a preferred embodiment of the present invention, in S2, the specific steps of extracting, washing and drying are extracting with EA, washing with saturated brine, and drying with anhydrous magnesium sulfate.

[0026] Furthermore, in a preferred embodiment of the present invention, in S1, the yield of the yellow solid product is 22.93%.

[0027] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0028] Example 1

[0029] This embodiment provides a luminescent compound containing 9,9-coupled carbazole and a preparation method thereof.

[0030] Preparation of 9.9-bi-1,1'-3,6-di-tert-butylcarbazole (Compound B): 1-Bromo-3,6-di-tert-butylcarbazole (Compound A) (1 g, 2.793 mmol) was added to a two-necked flask and dissolved in 10 ml of acetone. KMnO4 (1.1 g, 6.962 mmol) was then added and the mixture was deoxygenated with nitrogen. The reaction system was heated to 60°C and refluxed under a nitrogen atmosphere for 6 hours. The mixture was then cooled to room temperature and the product was extracted with DCM, washed with saturated sodium thiosulfate solution, and dried over anhydrous magnesium sulfate. The organic layer was collected by rotary evaporation and separated by silica gel column chromatography to obtain 0.644 g of the yellow-brown solid product, Compound C, in a yield of 64.59%.

[0031] Preparation of 3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole (BCZ-TRZ, Compound D): 9,9-bi-1,1'-3,6-di-tert-butylcarbazole (Compound B) (0.1 g, 0.140 mmol), 2,4-diphenyl-6-[4-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolane-2-yl)phenyl]-1,3,5-triazine (Compound D) were added into a two-necked flask in sequence. The reaction mixture was sealed and deoxygenated with nitrogen. TOL (6 mL) and K2CO3 solution (2 mL, 2.0 mol / L) that had been previously deoxygenated with nitrogen were injected using a long syringe. The mixture was reacted at 100°C in a nitrogen atmosphere for 24 hours. The product was extracted with EA, washed with saturated brine, and dried over anhydrous magnesium sulfate. The organic layer was collected by rotary evaporation and separated by silica gel column chromatography to obtain 0.0376 g of yellow solid product compound D with a yield of 22.93%.

[0032] Figure 2 This is a fluorescence luminescence photograph of the compound in tetrahydrofuran solution. It can be seen that the compound displays bright saturated pure white light in THF solution.

[0033] The UV absorption spectra of compound D in different solvents are as follows: Figure 3 As shown in the figure, there are strong absorption peaks within the short wave of 300nm, which corresponds to the π-π* transition absorption within the compound molecule. There is an absorption shoulder at 320nm, which corresponds to the n-π* transition absorption within the compound molecule. The absorption peak around 400nm should be due to the charge transfer within the molecule. In addition, there is still an absorption peak of lower intensity after 425nm, which may be due to the charge transfer effect generated by the space charge transfer effect between the carbazole and triazine units in the molecule.

[0034] The excitation spectra of compound D at 426 nm, 458 nm, 486 nm and 596 nm in THF solution are as follows: Figure 4As shown, the four peaks have inconsistent excitation spectra, indicating that the four peaks of compound D in THF solution come from different luminescence centers. Therefore, these four peaks constitute four luminescence channels of compound D in THF solution, proving that the compound is a multi-channel luminescent compound. At the same time, the fluorescence lifetimes of the four emission peaks (data shown in Table 1) further support the above results. The monitored lifetimes of the four emission peaks have different values, which also indicates that they have different radiation forms, indicating that the compound has multi-channel luminescence behavior.

[0035] Table 1 Luminescence lifetime data corresponding to the four emission peaks of compound D

[0036] sol 426nm 458nm 486nm 596nm THF 8.69ns / - 3.02ns / 4.47ms 3.36ns / 5.90ms 9.17ns / 7.08ms

[0037] In summary, the embodiments of the present invention select the introduction of a triphenyltriazine unit at the 1 or 1' position of the NN-coupled carbazole to construct a highly twisted fluorescent luminescent material, fully suppressing the ACQ effect and ensuring its efficient luminescence. The resulting compound exhibits LE-state luminescence of the coupled carbazole in solution, as well as CT-state luminescence generated by intramolecular charge transfer from the conjugated tert-butylcarbazole to the triazine unit, and CT-state luminescence generated by spatial charge transfer from the non-directly covalently linked tert-butylcarbazole to the triazine unit. Furthermore, the resulting compound exhibits multi-channel luminescence properties in both solution and solid states.

[0038] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

Claims

1. A luminescent compound containing 9,9-coupled carbazole, characterized in that: It is a compound with the following structural formula: The Chinese name is 3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole. The 9,9-coupled carbazole-containing luminescent compound obtains multi-channel luminescence properties in both solution and solid states.

2. A method for preparing a luminescent compound containing 9,9-coupled carbazole according to claim 1, characterized in that: The preparation method comprises the following steps: S1, Preparation of 9.9-Bis-1,1'-3,6-di-tert-butylcarbazole: 1-Bromo-3,6-di-tert-butylcarbazole was added to a two-necked flask and dissolved in acetone. KMnO4 was then added and the mixture was deoxygenated by nitrogen. The reaction system was heated to 60°C and refluxed under a nitrogen atmosphere. The mixture was cooled to room temperature and subjected to extraction, washing, and drying. The organic layer was collected by rotary evaporation and separated by silica gel column chromatography to obtain a yellowish-brown solid product, 9,9-bi-1,1'-3,6-di-tert-butylcarbazole. Preparation of S2,3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl)-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole: 9.9-Bis-1,1'-3,6-di-tert-butylcarbazole, 2,4-diphenyl-6-[4-(4,4,5,5,-tetramethyl-1,3,2-dioxaborolane-2-yl)phenyl]-1,3,5-triazine, Pd2(dba)3, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, and TBAI were added to a two-necked flask in sequence. The flask was sealed and nitrogen-filled and deoxygenated. TOL and K2CO3 solutions that had been previously nitrogen-filled and deoxygenated were injected using a long syringe. The flask was reacted at 100°C in a nitrogen atmosphere for 24 hours. After extraction, washing, and drying, the organic layer was collected by rotary evaporation and separated by silica gel column chromatography to obtain a yellow solid product, 3,6-di-tert-butyl-9-(3,6-di-tert-butyl-1-(4-(4,6-diphenyl-1,3,5-triazinyl-2-yl)phenyl)-9-hydrocarbazole-9-yl) -1-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9-hydrocarbazole.

3. The method for preparing a luminescent compound containing 9,9-coupled carbazole according to claim 2, wherein: In S1, the specific steps of extracting, washing and drying are extracting with DCM, washing with saturated sodium thiosulfate solution, and drying with anhydrous magnesium sulfate.

4. The method for preparing a luminescent compound containing 9,9-coupled carbazole according to claim 2, wherein: In S1, the reaction time is 6 hours.

5. The method for preparing a luminescent compound containing 9,9-coupled carbazole according to claim 2, wherein: In S1, the yield of the yellow-brown solid product was 64.59%.

6. The method for preparing a luminescent compound containing 9,9-coupled carbazole according to claim 2, wherein: In S2, the specific steps of extracting, washing and drying are extracting with EA, washing with saturated brine, and drying with anhydrous magnesium sulfate.

7. The method for preparing a luminescent compound containing 9,9-coupled carbazole according to claim 2, wherein: In S1, the yield of the yellow solid product was 22.93%.

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