Spirane-containing polymers, their preparation methods and applications

Abstract

The present invention discloses a spiro-containing polymer, a preparation method thereof and an application thereof. The structure of the polymer is shown in formula (I); wherein, x is 0.05 to 0.5, n is a natural number greater than or equal to 5; R1 and R2 are each independently selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl or C1-C6 alkyl-substituted naphthyl; R3, R4, R5, R6, R8, R9, R 10 and R 11 respectively represent substituents at any position on the benzene ring where they are located; R3 is selected from hydrogen or C1-C6 alkyl; R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl; R6 is selected from hydrogen or C1-C3 alkyl; R7 is selected from C1-C15 alkyl; R8 and R9 are each independently selected from hydrogen or C1-C6 alkyl; R 10 is selected from hydrogen or C1-C5 alkyl; R 11 is selected from hydrogen or C1-C3 alkyl. The polymer of the present invention can be used as a luminescent material for preparing an organic electroluminescent blue light emitting device.

Description

Technical Field

[0001] The present invention relates to a spiro-containing polymer, a preparation method and an application thereof, and particularly relates to a spiro-containing polymer having thermally activated delayed fluorescence properties, a preparation method and an application thereof. Background Art

[0002] Organic light-emitting diode (OLEDs) technology has unique advantages in terms of fast response, self-luminescence, and ultrathinness, and is one of the most promising technologies for future displays. OLEDs devices have a multi-layer structure, such as a glass substrate, an ITO layer, a light-emitting layer, a hole (electron) injection layer, a hole (electron) transport layer, etc. The design of the light-emitting layer material directly affects the efficiency and lifespan of the device. Developing light-emitting layer materials with low cost, strong stability, and high efficiency has always been a research hotspot in this field. The light-emitting layer materials are roughly divided into three generations. The third generation is thermally activated delayed fluorescence (TADF) materials. Due to their theoretically 100% internal quantum efficiency (IQE), no noble metals, thermal stability, and bipolar characteristics, TADF materials have become one of the most promising organic light-emitting materials today.

[0003] CN1699315A discloses a bis-fluorene spiro monomer, its polymer and uses. The bis-fluorene spiro polymer can be used as a blue light-emitting material for electroluminescence, but it does not mention the quantum yield of the polymer and the maximum external quantum efficiency of the light-emitting device.

[0004] CN1634927A discloses a non-benzenoid aromatic ring spirofluorene material, its synthesis and application. The spirofluorene material introduces a non-benzenoid aromatic ring into the fluorene system for light emission through a spiro structure. CN111465599A discloses a substituted aromatic amine for use in an organic electroluminescent device, which relates to a specific fluorene derivative. Summary of the Invention

[0005] In view of this, one object of the present invention is to provide a spiro-containing polymer. The spiro-containing polymer has thermally activated delayed fluorescence properties, a relatively high quantum yield, can be applied to organic electroluminescent blue light-emitting devices, and the external quantum efficiency of the device is relatively high. Another object of the present invention is to provide a preparation method of the spiro-containing polymer. Still another object of the present invention is to provide an application of the spiro-containing polymer in the preparation of organic electroluminescent blue light-emitting devices. The present invention achieves the above objects through the following technical solutions.

[0006] On the one hand, the present invention provides a spiro-containing polymer, and the structure of the polymer is shown in formula (I):

[0007]

[0008] wherein, x is 0.05 - 0.5, and n is a natural number greater than or equal to 5;

[0009] Wherein, R1 and R2 are each independently selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl or C1-C6 alkyl-substituted naphthyl;

[0010] Wherein, R3, R4, R5, R6, R8, R9, R 10 and R 11 respectively represent substituents at any position on the benzene ring where they are located;

[0011] R3 is selected from hydrogen or C1-C6 alkyl; R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl; R6 is selected from hydrogen or C1-C3 alkyl; R7 is selected from C1-C15 alkyl; R8 and R9 are each independently selected from hydrogen or C1-C6 alkyl; R 10 is selected from hydrogen or C1-C5 alkyl; R 11 is selected from hydrogen or C1-C3 alkyl.

[0012] For the spiro-containing polymer according to the present invention, preferably, R1 and R2 are the same and are selected from phenyl or C1-C3 alkyl-substituted phenyl; R3 is selected from hydrogen or C1-C3 alkyl.

[0013] For the spiro-containing polymer according to the present invention, preferably, R1 and R2 are the same and are both phenyl; R3 is hydrogen.

[0014] For the spiro-containing polymer according to the present invention, preferably, R4 and R5 are the same and are selected from hydrogen, diphenylamino or dibenzopyrrolyl.

[0015] For the spiro-containing polymer according to the present invention, preferably, R6, R8, R9 and R 11 are each independently selected from hydrogen, methyl or ethyl.

[0016] For the spiro-containing polymer according to the present invention, preferably, R7 is selected from straight-chain alkyl of C4-C12; R 10 is selected from methyl or ethyl.

[0017] For the spiro-containing polymer according to the present invention, preferably, x is 0.1 to 0.38.

[0018] On the other hand, the present invention also provides a preparation method of the spiro-containing polymer as described above, comprising the following steps:

[0019] (1) React the compound shown by formula (A) with the compound shown by formula (B) in the presence of alkyllithium to obtain an intermediate; carry out a ring-forming reaction on the intermediate in the presence of glacial acetic acid and hydrochloric acid to obtain a spiro-containing compound shown by formula (i);

[0020] (2) React the spiro-containing compound represented by formula (i) with the compound represented by formula (ii) and the compound represented by formula (iii), and then cap with the compound represented by formula (iv) to obtain a spiro-containing polymer represented by formula (I);

[0021]

[0022]

[0023] In formula (A), formula (B), formula (i) and formula (iii), Y is selected from chlorine, bromine or iodine;

[0024] In formula (A) and formula (i), R1 and R2 are each independently selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl or C1-C6 alkyl-substituted naphthyl; R3 and R4 each represent a substituent at any position on the benzene ring where they are located; R3 is selected from hydrogen or C1-C6 alkyl; R4 is selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl;

[0025] In formula (A) and formula (i), R5 represents a substituent at any position on the benzene ring where it is located; R5 is selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl;

[0026] In formula (B) and formula (i), R6 represents a substituent at any position on the benzene ring where it is located, and R6 is selected from hydrogen or C1-C3 alkyl;

[0027] In formula (ii), Z is selected from a boronic acid group or a borate group; R7 is selected from C1-C15 alkyl; R8 and R9 each represent a substituent at any position on the benzene ring where they are located; R8 and R9 are each independently selected from hydrogen or C1-C6 alkyl;

[0028] In formula (iii) and formula (iv), R 10 and R 11 each represent a substituent at any position on the benzene ring where they are located; R 10 is selected from hydrogen or C1-C5 alkyl; R 11 is selected from hydrogen or C1-C3 alkyl.

[0029] According to the preparation method of the present invention, preferably:

[0030] In step (1), the alkyllithium is n-butyllithium;

[0031] In step (2), the spiro-containing compound represented by formula (i) reacts with the compound represented by formula (ii) and the compound represented by formula (iii) in the presence of a palladium catalyst, a quaternary ammonium salt phase transfer catalyst, and a phosphine ligand at 80-98 °C for 56-90 h; after the reaction is completed, the compound represented by formula (iv) is added for capping to obtain a spiro-containing polymer represented by formula (I).

[0032] On the other hand, the present invention also provides the application of the spiro-containing polymer as described above in the preparation of organic electroluminescent devices.

[0033] The spiro-containing polymer of the present invention has a relatively high quantum yield. The spiro-containing polymer of the present invention can be used as a luminescent material in organic electroluminescent blue light emitting devices, and has a relatively high external quantum efficiency. Detailed implementation manners

[0034] The following further illustrates the present invention with specific examples, but the protection scope of the present invention is not limited thereto.

[0035] <Spiro-containing polymer>

[0036] The structure of the spiro-containing polymer of the present invention is as shown in formula (I):

[0037]

[0038] The spiro-containing polymer of the present invention includes four main parts: an electron acceptor, an electron donor, a spiro structure, and a conjugated main chain structure. In the above structure, the triazinylphenyl structure belongs to the electron acceptor, the part between the electron acceptor and the spiro structure is the electron donor part, and the carbazole part with 1-x molar fraction belongs to the conjugated main chain structure. By introducing a spiro structure into the conjugated main chain structure of such a polymer, the regulation of photophysical properties, the optimization of carrier transport, and the effective suppression of spectral red shift can be achieved simultaneously. At the same time, by selecting TADF (thermally activated delayed fluorescence) molecules with different electron donor-acceptor structures to construct spiro-containing monomers, the regulation of photophysical properties such as the luminescence color, exciton decay, and conversion rate of the molecule can be achieved, and the quantum yield can reach more than 80%. Such a polymer has good thermal stability, electrochemical stability, and excellent luminescence performance. Such a polymer can be used as a luminescent material in the luminescent layer of an organic electroluminescent device to obtain a blue light emitting device, and the external quantum efficiency of the device can reach more than 10%, preferably more than 16%, and more preferably more than 17%.

[0039] Due to the fact that TADF small molecules are extremely easy to form conjugation with the polymer main chain, which in turn leads to the red shift of fluorescence. Based on this shortcoming, the sp of the TADF small molecule with a spiro structure in the present invention located at the donor site 3Hybrid carbon can also disrupt the conjugation between the TADF molecule and the host, ultimately avoiding the red shift of fluorescence. The inventors believe that this may be because: on the one hand, the two perpendicular planes connected by sp 3 hybrid carbon increase the torsion of the molecule, avoiding the conjugation effect between molecules; on the other hand, when the donor unit is connected to a suitable acceptor unit, the large steric hindrance can also sufficiently separate the HOMO and LUMO, resulting in a small energy gap. This polymer of the present invention can effectively separate the conjugated main chain from the TADF unit, thereby avoiding excessive red shift and broadening of the spectrum, which affect the color purity of the light-emitting device.

[0040] In formula (I), x represents the molar fraction of the structural unit. x is 0.05 to 0.5, preferably 0.1 to 0.5, more preferably 0.15 to 0.5, still more preferably 0.16 to 0.45, and further preferably 0.17 to 0.38. In certain embodiments, x is 0.104. In other embodiments, x is 0.169. In yet other embodiments, x is 0.372.

[0041] In formula (I), n represents the degree of polymerization. n is a natural number greater than or equal to 5, preferably a natural number greater than or equal to 5 and less than or equal to 50, and more preferably a natural number greater than or equal to 10 and less than or equal to 30.

[0042] In certain embodiments, the molecular weight of the resulting polymer is 5000 to 100000, more preferably 10000 to 50000, and still more preferably 10000 to 20000. The polydispersity index (PDI) is 1.4 to 2.5.

[0043] R1 is selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl, or C1-C6 alkyl-substituted naphthyl, preferably selected from phenyl, C1-C6 alkyl-substituted phenyl, naphthyl, and more preferably selected from phenyl, C1-C3 alkyl-substituted phenyl. Examples of C1-C6 alkyl include but are not limited to methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl. According to a specific embodiment of the present invention, R1 is phenyl.

[0044] R2 is selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl, or C1-C6 alkyl-substituted naphthyl, preferably selected from phenyl, C1-C6 alkyl-substituted phenyl, naphthyl, and more preferably selected from phenyl, C1-C3 alkyl-substituted phenyl. Examples of C1-C6 alkyl include but are not limited to methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl. According to a specific embodiment of the present invention, R2 is phenyl.

[0045] R3, R4, R5, R6, R8, R9, R 10 and R11 Each represents a substituent at any position on the benzene ring to which it belongs. "Any position on the benzene ring to which it belongs" means "any position on the benzene ring to which it belongs that is not substituted by a substituent".

[0046] R3 is selected from hydrogen or a C1-C6 alkyl group. Preferably, R3 is selected from hydrogen or a C1-C3 alkyl group. More preferably, R3 is selected from hydrogen, methyl or ethyl. In certain specific embodiments, R3 is hydrogen.

[0047] R4 is selected from hydrogen, a C1-C6 alkyl group, a diphenylamino group or a dibenzopyrrolyl group. Preferably, R4 is selected from hydrogen, a diphenylamino group or a dibenzopyrrolyl group. More preferably, R4 is hydrogen. In the present invention, when R4 is selected from a diphenylamino group or a dibenzopyrrolyl group, R4 is preferably at the para-position or meta-position of the amino group on the benzene ring.

[0048] R5 is selected from hydrogen, a C1-C6 alkyl group, a diphenylamino group or a dibenzopyrrolyl group. Preferably, R5 is selected from hydrogen, a diphenylamino group or a dibenzopyrrolyl group. More preferably, R5 is hydrogen. In the present invention, when R5 is selected from a diphenylamino group or a dibenzopyrrolyl group, R5 is preferably at the para-position or meta-position of the amino group on the benzene ring.

[0049] According to a specific embodiment of the present invention, R4 and R5 are the same and are both hydrogen.

[0050] R6 is selected from hydrogen or a C1-C3 alkyl group. Preferably, R6 is selected from hydrogen, methyl or ethyl. More preferably, R6 is hydrogen.

[0051] R7 is selected from a C1-C15 alkyl group, preferably selected from a C3-C12 alkyl group, more preferably selected from a straight-chain C4-C12 alkyl group. Examples of the C1-C15 alkyl group include, but are not limited to, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl.

[0052] R8 is selected from hydrogen or a C1-C6 alkyl group, preferably selected from hydrogen or a C1-C3 alkyl group, more preferably selected from hydrogen, methyl or ethyl. Examples of the C1-C6 alkyl group include, but are not limited to, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl.

[0053] R9 is selected from hydrogen or a C1-C6 alkyl group, preferably selected from hydrogen or a C1-C3 alkyl group, more preferably selected from hydrogen, methyl or ethyl. Examples of the C1-C6 alkyl group include, but are not limited to, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl.

[0054] According to a specific embodiment of the present invention, R8 and R9 are the same and are both hydrogen.

[0055] R 10 is selected from hydrogen or a C1-C5 alkyl group, preferably selected from a C1-C5 alkyl group, more preferably selected from a C1-C3 alkyl group. Examples of the C1-C5 alkyl group include, but are not limited to, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, and n-pentyl. According to a specific embodiment of the present invention, R 10 is methyl.

[0056] R 11 is selected from hydrogen or a C1-C3 alkyl group, preferably selected from hydrogen or methyl, more preferably hydrogen.

[0057] According to some specific embodiments of the present invention, the spiro-containing polymer is a structure represented by formula (II), (III), or (IV):

[0058]

[0059]

[0060] In formula (II), (III), and (IV), x is 0.05 to 0.5, and n is a natural number from 6 to 25.

[0061] <Preparation method>

[0062] The preparation method of the spiro-containing polymer of the present invention includes: (1) synthesizing a spiro-containing compound represented by formula (i); (2) synthesizing a spiro-containing polymer. Optionally, it further includes the step of synthesizing a compound represented by formula (A). The following is a detailed introduction.

[0063] Synthesize the compound represented by formula (A)

[0064] Reacting the compound represented by formula (E) with the compound represented by formula (D) in the presence of potassium tert-butoxide to obtain the compound represented by formula (A).

[0065]

[0066] In formula (E) and formula (A), R1 is selected from a C1-C8 alkyl group, phenyl, a C1-C6 alkyl-substituted phenyl group, naphthyl, or a C1-C6 alkyl-substituted naphthyl group, preferably selected from phenyl, a C1-C6 alkyl-substituted phenyl group, naphthyl, more preferably selected from phenyl and a C1-C3 alkyl-substituted phenyl group. Examples of the C1-C6 alkyl group include, but are not limited to, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, and n-hexyl. According to a specific embodiment of the present invention, R1 is phenyl.

[0067] R2 is selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl or C1-C6 alkyl-substituted naphthyl, preferably selected from phenyl, C1-C6 alkyl-substituted phenyl, naphthyl, more preferably selected from phenyl, C1-C3 alkyl-substituted phenyl. Examples of C1-C6 alkyl include but are not limited to methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl. According to a specific embodiment of the present invention, R2 is phenyl.

[0068] R3 represents a substituent at any position on the benzene ring where it is located. R3 is selected from hydrogen or C1-C6 alkyl, preferably, R3 is selected from hydrogen or C1-C3 alkyl, more preferably, R3 is selected from hydrogen, methyl or ethyl. In certain specific embodiments, R3 is hydrogen.

[0069] In formula (D), R4 represents a substituent at any position on the benzene ring where it is located. R4 is selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl, preferably, R4 is selected from hydrogen, C1-C6 alkyl or diphenylamino. More preferably, R4 is hydrogen. In the present invention, when R4 is selected from diphenylamino or dibenzopyrrolyl, R4 is preferably located at the para position or meta position of the amino group on the benzene ring. Y is a halogen, preferably selected from chlorine, bromine or iodine, preferably chlorine or bromine, more preferably bromine.

[0070] In formula (D) and formula (A), R5 represents a substituent at any position on the benzene ring where it is located except the 2-position and 6-position. R5 is selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl, preferably, R5 is selected from hydrogen, C1-C6 alkyl or diphenylamino. More preferably, R5 is hydrogen. In the present invention, when R5 is selected from diphenylamino or dibenzopyrrolyl, R5 is preferably located at the para position or meta position of the amino group on the benzene ring.

[0071] In certain specific embodiments, both R1 and R2 are phenyl, R3, R4 and R5 are all hydrogen, and Y is bromine.

[0072] In the above reaction, the molar ratio of the compounds represented by formula (D) and formula (E) is 1.1 to 1.8:1, preferably 1.2 to 1.7:1, more preferably 1.4 to 1.6:1. The molar ratio of potassium tert-butoxide (t-BuOK) to the compound represented by formula (E) is 1.95 to 2.5:1, preferably 2.0 to 2.4:1, more preferably 2.1 to 2.3:1. N,N-Dimethylformamide (DMF) is used as the reaction solvent, and its volume-mass ratio to the compound represented by formula (E) is 15 to 35 mL:1 g, preferably 20 to 30 mL:1 g.

[0073] In certain specific embodiments, potassium tert-butoxide is added to a reaction flask, and the air is evacuated and filled multiple times. Then, DMF is added to the reaction flask and stirred until the potassium tert-butoxide dissolves. The temperature is lowered using an ice-water bath, and a DMF solution containing the compound shown in formula (D) is added dropwise, followed by stirring for 50 min to 1.5 h. Then, the ice-water bath is removed, and the temperature is raised to 35 - 50 °C, and the reaction is continued for 3 - 6 h. The compound shown in formula (E) is added, and then the temperature is raised to 75 - 85 °C, and the reaction is carried out for 9 - 18 h. After the reaction is completed, saturated brine is added to quench the reaction, and extraction is performed multiple times with dichloromethane or chloroform. The extracted organic phases are combined, dried (anhydrous magnesium sulfate or anhydrous sodium sulfate can be used), filtered, and the filtrate is concentrated (a small amount of silica gel powder can be added during concentration) to obtain a crude product. The crude product is subjected to column chromatography, and the eluent is petroleum ether:dichloromethane = 7.5:1 (volume ratio). After column chromatography, the obtained product is recrystallized, and the solvents used for recrystallization are ethanol and toluene. The compound product shown in formula (A) is obtained and can be used as a raw material for the next reaction.

[0074] Synthesize the spiro-containing compound represented by formula (i)

[0075] Specifically, it includes the synthesis of the compound shown in formula (C) (i.e., the intermediate) and the synthesis steps of the spiro-containing compound shown in formula (i). The following is a detailed introduction.

[0076] The compound shown in formula (A) is reacted with the compound shown in formula (B) in the presence of an alkyllithium to obtain the compound shown in formula (C). The alkyllithium is preferably n-butyllithium.

[0077]

[0078] In formula (B), R6 represents a substituent at any position on the benzene ring. R6 is selected from hydrogen or C1-C3 alkyl. Preferably, R6 is selected from hydrogen, methyl, or ethyl. More preferably, R6 is hydrogen. Y is selected from chlorine, bromine, or iodine. Preferably, Y is chlorine or bromine. More preferably, Y is bromine.

[0079] In the above reaction, the concentration of n-butyllithium (n-BuLi) is 2 - 2.6 M, preferably 2.2 - 2.5 M. The molar ratio of the compound shown in formula (B) to the compound shown in formula (A) is 1.15 - 1.25:1, preferably 1.18 - 1.22:1, more preferably 1.2 - 1.21:1. The reaction solvent is tetrahydrofuran (THF). The molar ratio of n-butyllithium to the compound shown in formula (A) is 1.18 - 1.22:1, preferably 1.2 - 1.21:1.

[0080] In certain specific embodiments, the compound represented by formula (A) is added to a reaction flask and dissolved in THF. The temperature is lowered to -65°C to -78°C, and n-butyllithium is added dropwise to the reaction flask. The reaction is carried out for 1.5 to 3 h, and then a THF solution of the compound represented by formula (B) is added dropwise to the reaction system. The reaction is carried out for 8 to 14 h. After the reaction is completed, saturated brine is added to quench the reaction, and the reactants are extracted multiple times with dichloromethane or chloroform. The extracted organic phase is dried, filtered, and the filtrate is concentrated to obtain a crude product. The crude product is separated by column chromatography, and the eluent is selected as petroleum ether:dichloromethane = 5:1 (volume ratio). The product after column chromatography is recrystallized with ethanol-toluene, filtered, and dried to obtain the compound product represented by formula (C), which is used as a raw material for the next reaction.

[0081] The compound represented by formula (C) is subjected to a cyclization reaction in the presence of glacial acetic acid and hydrochloric acid to obtain a spiro-containing compound represented by formula (i).

[0082]

[0083] In the above reaction, the volume-to-mass ratio of glacial acetic acid to the compound represented by formula (C) is 15 to 35 mL:1 g. The hydrochloric acid used is concentrated hydrochloric acid, and its concentration can be 10 to 12 mol / L. The volume-to-mass ratio of concentrated hydrochloric acid to the compound represented by formula (C) is 1 to 3 mL:1 g.

[0084] In certain specific embodiments, the compound represented by formula (C) is mixed with glacial acetic acid and reacted under reflux for 20 to 40 min, and then concentrated hydrochloric acid is added dropwise. After the addition is complete, the reaction is carried out for 10 to 15 h. After the reaction is completed, solid-liquid separation is carried out. The organic phase is concentrated, and the concentrated product is separated by column chromatography. The eluent is selected as petroleum ether:dichloromethane = 15:1 (volume ratio). The product after column chromatography is recrystallized with ethanol-toluene, filtered, and dried to obtain the compound product represented by formula (i), which is used as a raw material for the next reaction.

[0085] Spiro-containing polymer

[0086] The spiro-containing compound represented by formula (i) is reacted with the compound represented by formula (ii) and the compound represented by formula (iii), and then capped with the compound represented by formula (iv) to obtain a spiro-containing polymer represented by formula (I).

[0087]

[0088] In formula (ii), R7 is selected from C1-C15 alkyl groups, preferably selected from C3-C12 alkyl groups, more preferably selected from straight-chain C4-C12 alkyl groups. R8 is selected from hydrogen or C1-C6 alkyl groups, preferably selected from hydrogen or C1-C3 alkyl groups, more preferably selected from hydrogen, methyl or ethyl. R9 is selected from hydrogen or C1-C6 alkyl groups, preferably selected from hydrogen or C1-C3 alkyl groups, more preferably selected from hydrogen, methyl or ethyl. Z is selected from a boronic acid group (see formula (F) below) or a boronate group. The boronate group can be a pinacol boronate group, see formula (G) below.

[0089]

[0090] In formulas (iii) and (iv), R 10 and R 11 respectively represent substituents at any position on the benzene ring where they are located. R 10 is selected from hydrogen or C1-C5 alkyl groups, preferably selected from C1-C3 alkyl groups, more preferably methyl or ethyl. R 11 is selected from hydrogen or C1-C3 alkyl groups, preferably hydrogen or methyl, more preferably hydrogen. In formula (iii), Y is selected from chlorine, bromine or iodine, preferably chlorine or bromine, more preferably bromine.

[0091] In the above reaction, the catalyst used is a palladium catalyst, preferably the Pd(0)(dba)2 catalyst. A quaternary ammonium salt is used as a phase transfer catalyst, preferably methyltrioctylammonium chloride (Aliquat® 336). A phosphine ligand is used as an auxiliary agent, and the phosphine ligand is preferably ((R)-3-(tert-butyl)-4-(2,6-dimethoxyphenyl)-2,3-dihydrobenzo[d][1,3]oxaphospholene)) (denoted as rac-BI-DIMe). And a base reagent is used, and the base reagent is preferably potassium phosphate. The solvent used is a mixture of water and toluene, and the volume ratio of water to toluene is 1:3.5 to 4.5. The reaction temperature is 80-98 °C, preferably 90-96 °C. The reaction time is 56-90 h, preferably 65-80 h, more preferably 68-75 h.

[0092] In the above reaction, the feeding ratios of the compounds represented by formula (i), formula (ii) and formula (iii) can be controlled to control the value of x in the obtained polymer, so as to obtain spiro-containing polymers with different properties.

[0093] In certain specific embodiments, the compound represented by formula (i), the compound represented by formula (ii), the compound represented by formula (iii), a palladium catalyst, potassium phosphate, methyltrioctylammonium chloride, and the phosphine ligand rac-BI-DIMe are sequentially added to a reaction flask, and then deionized water and toluene are added. The temperature is raised to 80 - 98 °C, and the reaction is carried out for 65 - 80 h. Then bromobenzene is added for capping, and the reaction is continued for 15 - 28 h. After the reaction is completed, saturated brine is added to quench the reaction, and extraction is carried out with dichloromethane or chloroform. The extracted organic phase is dried, filtered, and concentrated to obtain a crude polymer. Then the obtained crude polymer is dissolved again in THF, and it is slowly dropped into methanol for full precipitation. The lower-layer precipitate is filtered out and placed in a Soxhlet extractor for washing with anhydrous ethanol as the solvent, and extraction is carried out for 25 - 55 h, followed by drying to finally obtain a polymer containing a spiro ring.

[0094] <Application>

[0095] The present invention also provides the application of the polymer containing a spiro ring as described above in the preparation of an organic electroluminescent device. The organic electroluminescent device is a blue light-emitting device.

[0096] The following describes the instruments used in the preparation examples, examples, and experimental examples:

[0097] The nuclear magnetic resonance data and mass spectrometry data are obtained by a Bruker Ascend 400 MHz nuclear magnetic resonance spectrometer (Bruker, Germany) and a Waters Xevo-G2-SQ-TOFMS mass spectrometry system (Waters, USA), respectively.

[0098] The fluorescence data are obtained by a Hitachi F-7000 fluorescence spectrometer (Hitachi, Japan) and an FLS-980 transient fluorescence spectrometer (Edinburgh Instruments, UK). The brightness data are obtained by a PR670 spectro-radiance meter (Pioneer Technology, Taiwan, China).

[0099] Preparation Example 1 - Synthesis of the compound represented by formula (A)

[0100] The reaction equation is as follows:

[0101]

[0102] Potassium tert-butoxide (i.e., t-BuOK, 6.75 mmol, 757 mg) was added to a reaction flask, a condenser was connected and sealed, and the air was evacuated and filled three times. 20 mL of dimethylformamide (DMF) was added to the reaction flask, and potassium tert-butoxide was dissolved by stirring; the temperature was lowered in an ice-water bath, and a DMF solution containing 2-bromodiphenylamine (2-bromodiphenylamine was 4.5 mmol, 1116 mg) was added dropwise, and the mixture was stirred for 1 h. The ice-water bath was removed, the temperature was raised to 40 °C, and the reaction was continued for 4 h. 4-Fluorophenyl-4,6-diphenyl-1,3,5-triazine (3 mmol, 982 mg) was added, and then the temperature was raised to 80 °C, and the reaction was carried out for 12 h. After the reaction was completed, saturated brine was added to quench the reaction, and the reactants were extracted with dichloromethane multiple times until there was no product spot in the extracted organic phase (detected by TLC). The extracted organic phase was dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated to obtain a crude product. The crude product was separated by column chromatography, and the eluent was petroleum ether:dichloromethane = 7.5:1 (volume ratio). The product after column chromatography was recrystallized with ethanol-toluene, filtered, and dried to obtain the compound product shown in formula (A), which was 1047 mg of yellow powder with a yield of 63%. The structure of this product was identified, and the results are as follows:

[0103] 1 H NMR (400 MHz, CDCl3) δ 8.83 - 8.74 (multiplet, 4H), 8.72 - 8.62 (multiplet, 2H), 7.74 (doubled doublet, J = 8.0, 1.4 Hz, 1H), 7.67 - 7.54 (multiplet, 6H), 7.46 - 7.32 (multiplet, 4H), 7.27 - 7.19 (multiplet, 3H), 7.19 - 7.11 (multiplet, 1H), 7.10 - 7.00 (multiplet, 2H).

[0104] 13 C NMR (101 MHz, CDCl3) δ 171.31, 171.15, 150.94, 145.75, 144.66, 136.53, 134.68, 132.29, 131.83, 130.31, 129.37, 129.10, 128.89, 128.58, 128.45, 128.11, 124.14, 123.96, 123.92, 119.16.

[0105] Calculated value [M + H] 555.1106; Measured value [M + H] 555.1190.

[0106] Preparation Example 2 - Synthesis of the intermediate compound of formula (C)

[0107] The reaction equation is as follows:

[0108]

[0109] Add the triphenyltriazine-2-bromo-diphenylamine obtained in Preparation Example 1 (i.e., the compound shown in formula (A), 4 mmol, 2220 mg) to a reaction flask. Place 4,4'-dibromobenzophenone (4.8 mmol, 1632 mg) in a constant pressure dropping funnel, and evacuate and refill the system 5 times. Add 20 mL of THF to the reaction flask and stir until the triphenyltriazine-2-bromo-diphenylamine is completely dissolved. Cool down with liquid nitrogen and then evacuate and refill the system 3 times. At -78 °C, add n-butyllithium (n-BuLi, 2.4 M, 4.8 mmol) dropwise to the reaction flask and react for 2 h. The system turns into a translucent orange-red color. Supplement liquid nitrogen to maintain the reaction temperature at -78 °C. Add an appropriate amount of THF to the constant pressure dropping funnel to completely dissolve 4,4'-dibromobenzophenone, and slowly add it dropwise to the reaction flask and react for 10 h. After the reaction is completed, add saturated brine to quench the reaction. Extract the reactants with dichloromethane multiple times until there is no product spot in the extracted organic phase (detected by TLC). Dry the extracted organic phase with anhydrous magnesium sulfate, filter, concentrate the filtrate to obtain a crude product. The crude product is separated by column chromatography, and the eluent is petroleum ether:dichloromethane = 5:1 (volume ratio). The product after column chromatography is recrystallized with ethanol-toluene, filtered, and dried to obtain the compound product shown in formula (C), which is 1699 mg of a pale yellow powder with a yield of 52%. The structure of this product was identified as follows:

[0110] 1 H NMR (400 MHz, CDCl3) δ 8.81 - 8.67 (multiplet, 4H), 8.53 - 8.43 (multiplet, 2H), 7.66 - 7.52 (multiplet, 6H), 7.45 - 7.32 (multiplet, 1H), 7.27 - 7.16 (multiplet, 6H), 7.13 (triplet of doublets, J = 7.4, 6.7, 1.3 Hz, 2H), 7.08 - 6.98 (multiplet, 3H), 6.97 - 6.85 (multiplet, 6H), 6.82 (doublet of doublets, J = 8.3, 1.6 Hz, 1H), 6.60 (s, 1H).

[0111] 13 C NMR (101 MHz, CDCl3) δ 171.40, 170.94, 151.33, 145.97, 144.62, 144.25, 143.99, 143.59, 136.39, 133.04, 132.39, 131.66, 130.86, 130.76, 130.01, 129.80, 129.30, 128.96, 128.60, 126.63, 124.23, 124.03, 121.83, 121.48, 82.60.

[0112] MS: 816.0922.

[0113] Preparation Example 3 - Synthesis of the compound of formula (i)

[0114] The reaction equation is as follows:

[0115]

[0116] Add triphenyltriazine-2-(4,4'-dibromobenzhydrol)-diphenylamine (i.e., the compound shown in formula (C), 2 mmol, 1628 mg) obtained in Preparation Example 2 into a reaction flask, connect a condenser and a constant pressure dropping funnel and seal it, and evacuate and refill with gas three times. Subsequently, add glacial acetic acid (50 ml) into the reaction flask, reflux at 120 °C for 30 min, and dropwise add concentrated hydrochloric acid (12 mol / L, 2.5 mL) using a constant pressure dropping funnel, and react for 12 h. After the reaction is completed, pour off the supernatant, and wash the solid at the bottom with ethanol three times. Concentrate the organic phase, separate the concentrated product by column chromatography, and use petroleum ether:dichloromethane = 15:1 (volume ratio) as the eluent. The product after passing through the column is recrystallized with ethanol-toluene, filtered, and dried to obtain the compound product shown in formula (i), triphenyltriazine-spiro[acridine-9,9'-(4-bromobenzene)] (denoted as DPAC-Br-TRZ, 669 mg, yield 42%). The second product is the by-product diphenyltriazine-spiro[acridine-10-phenyl-9,9'-(4-bromobenzene)] (denoted as DPAC-ph-Br-TRZ, 716 mg, yield 45%). The results of the structural identification of the product having the structure shown in formula (i) are as follows:

[0117] 1 H NMR (400 MHz, CDCl3): δ 9.00 - 8.91 (multiplet, 1H), 8.84 - 8.74 (multiplet, 2H), 7.69 - 7.54 (multiplet, 3H), 7.47 - 7.37 (multiplet, 2H), 7.35 - 7.28 (multiplet, 1H), 7.08 (triplet, J = 8.5, 7.0, 1.7 Hz, 1H), 6.97 - 6.80 (multiplet, 4H), 6.52 (doublet of doublets, J = 8.3, 1.2 Hz, 1H).

[0118] 13 C NMR (101 MHz, CDCl3): δ 171.86, 170.97, 145.07, 144.39, 141.76, 136.38, 136.04, 132.73, 132.05, 131.46, 131.36, 130.94, 129.73, 129.02, 128.73, 128.48, 127.40, 120.74, 120.70, 114.32, 56.13.

[0119] MS: 797.0921.

[0120] Example 1 - Synthesis of the spiro-containing polymer polyTD-1

[0121] The reaction equation is as follows:

[0122]

[0123] The DPAC-Br-TRZ obtained in Preparation Example 3 (i.e., the compound shown in formula (i), 0.1 mmol, 79.9 mg), Cz-C6-BPD (i.e., the compound shown in formula (ii), 0.5 mmol, 251.7 mg), 1,2-dibromotetramethylbenzene (i.e., the compound shown in formula (iii), 0.4 mmol, 116.8 mg), Pd(0)(dba)2 (0.025 mmol, 15 mg), K3PO4 (1.5 mmol, 319 mg), Aliquat® 336 (40 mg), rac-BI-DIMe (0.05 mmol, 21 mg) were successively added to a reaction flask, and a condenser was connected. The air was evacuated 3 times. 5 mL of deionized water and 20 mL of dried toluene were added to the reaction system, and the temperature was raised to 95 °C and the reaction was carried out for 72 h. Then, 0.25 mL of bromobenzene was added for capping and the reaction was continued for 24 h. After the reaction was completed, an appropriate amount of saturated brine was added, and the mixture was extracted with dichloromethane. The extracted organic phase was dried over anhydrous magnesium sulfate, filtered, concentrated to obtain a crude polymer. Then the obtained crude polymer was redissolved in THF and slowly added dropwise to methanol for full precipitation. The lower layer precipitate was filtered out and placed in a Soxhlet extractor for washing with anhydrous ethanol as the solvent. After extraction for 48 h, it was dried to finally obtain a pale yellow polymer, denoted as polyTD-1.

[0124] Example 2 - Synthesis of the spiro-containing polymer polyTD-2

[0125] The difference between this example and Example 1 is only the amounts of raw materials used. In this example, DPAC-Br-TRZ (0.2 mmol, 159.8 mg), Cz-C6-BPD (0.5 mmol, 251.7 mg), 1,2-dibromotetramethylbenzene (0.1 mmol, 29.2 mg). The obtained polymer is denoted as polyTD-2.

[0126] Example 3 - Synthesis of the spiro-containing polymer polyTD-3

[0127] The difference between this example and Example 1 is only that the raw material dosages are different. In this example, DPAC-Br-TRZ (0.4 mmol, 319.6 mg), Cz-C6-BPD (0.5 mmol, 251.7 mg), 1,2-dibromotetramethylbenzene (0.3 mmol, 87.6 mg). The obtained polymer is denoted as polyTD-3.

[0128] The elemental contents of the spiro-containing polymers obtained in Examples 1-3 and the value of x are shown in Table 1 below.

[0129] Table 1

[0130] Number Polymer N [wt%] C [wt%] H [wt%] C / N x Example 1 PolyTD-1 4.39 84.17 6.848 22.41 0.104 Example 2 PolyTD-2 5.83 83.07 6.334 16.64 0.372 Example 3 PolyTD-3 4.66 81.23 6.633 20.33 0.169

[0131] Experimental Example 1

[0132] I. The characterization data of the spiro-containing polymers in Examples 1-3 are shown in Table 2.

[0133] Table 2

[0134]

[0135] As can be seen from the table, the spiro-containing polymers of the present invention can achieve the regulation of photophysical properties, the optimization of carrier transport, and effectively inhibit the spectral red shift, and can achieve the regulation of photophysical properties such as the luminescent color of molecules, exciton decay, and conversion rate. The quantum yield can reach more than 80%.

[0136] II. Organic electroluminescent devices

[0137] The spiro-containing polymers polyTD-1, polyTD-2, and polyTD-3 obtained in Examples 1-3 are respectively applied to OLEDs (organic light-emitting diodes), and the substrates are all glass. The layers of the devices are shown in Table 3.

[0138] Table 3

[0139]

[0140] Among them, ITO is indium tin oxide; PEDOT is a polymer of EDOT (3,4-ethylenedioxythiophene monomer), and PSS is polystyrene sulfonate; PVK is polyvinylcarbazole; mCPCN is 9-[3-(9H-carbazol-9-yl)phenyl]-9H-carbazole-3-carbonitrile; DPEPO is bis[2-((oxo)diphenylphosphino)phenyl] ether; TmPyPB is 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl] dipyridine; LiF is lithium fluoride; Al is aluminum. The manufacturing method of these OLEDs can refer to those known in the art.

[0141] The performance of these OLEDs devices was tested and the results are shown in Table 4 below.

[0142] Table 4

[0143]

[0144] As can be seen from the table, the spirocyclic polymer obtained in the present invention is used as a luminescent material in the luminescent layer, and a blue light OLED device is assembled using a solution processing method. The maximum external quantum efficiency can reach more than 17%, showing good application prospects.

[0145] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement and substitution that can be conceived by those skilled in the art shall fall within the scope of the present invention.

Claims

1. A spiro-containing polymer, characterized in that, The structure of the polymer is shown in formula (I): wherein, x is 0.05 - 0.5, and n is a natural number greater than or equal to 5; wherein, R1 and R2 are each independently selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl or C1-C6 alkyl-substituted naphthyl; Among them, R3, R4, R5, R6, R8, R9, R 10 and R 11 respectively represent substituents at any position on the benzene ring where they are located; R3 is selected from hydrogen or C1-C6 alkyl; R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl; R6 is selected from hydrogen or C1-C3 alkyl; R7 is selected from C1-C15 alkyl; R8 and R9 are each independently selected from hydrogen or C1-C6 alkyl; R 10 is selected from hydrogen or C1-C5 alkyl; R 11 is selected from hydrogen or C1-C3 alkyl.

2. The polymer according to claim 1, wherein R1 and R2 are the same and are selected from phenyl or C1-C3 alkyl-substituted phenyl; R3 is selected from hydrogen or C1-C3 alkyl.

3. The polymer according to claim 1, wherein R1 and R2 are the same and are phenyl; R3 is hydrogen.

4. The polymer according to claim 1, characterized in that, R4 and R5 are the same and are selected from hydrogen, diphenylamino or dibenzopyrrolyl.

5. The polymer according to claim 1, wherein R6, R8, R9, and R 11 are each independently selected from hydrogen, methyl, or ethyl.

6. The polymer according to claim 1, characterized in that, R7 is selected from straight-chain alkyl groups having 4 to 12 carbon atoms; R 10 is selected from methyl or ethyl.

7. The polymer according to claim 1, wherein x is 0.1 - 0.

38.

8. The preparation method of the spiro-containing polymer according to any one of claims 1 to 7, characterized in that, It includes the following steps: (1) React the compound shown in formula (A) with the compound shown in formula (B) in the presence of alkyllithium to obtain an intermediate; carry out a cyclization reaction on the intermediate in the presence of glacial acetic acid and hydrochloric acid to obtain a spiro-containing compound shown in formula (i); (2) React the spiro-containing compound shown in formula (i) with the compound shown in formula (ii) and the compound shown in formula (iii), and then cap with the compound shown in formula (iv) to obtain a spiro-containing polymer shown in formula (I); In formula (A), formula (B), formula (i) and formula (iii), Y is a halogen; In formula (A) and formula (i), R1 and R2 are each independently selected from C1-C8 alkyl, phenyl, C1-C6 alkyl-substituted phenyl, naphthyl or C1-C6 alkyl-substituted naphthyl; R3 and R4 respectively represent substituents at any position on the benzene ring where they are located; R3 is selected from hydrogen or C1-C6 alkyl; R4 is selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl; In formula (A) and formula (i), R5 represents a substituent at any position on the benzene ring where it is located; R5 is selected from hydrogen, C1-C6 alkyl, diphenylamino or dibenzopyrrolyl; In formula (B) and formula (i), R6 represents a substituent at any position on the benzene ring where it is located, and R6 is selected from hydrogen or C1-C3 alkyl; In formula (ii), Z is selected from borate group or borate ester group; R7 is selected from C1-C15 alkyl; R8 and R9 respectively represent substituents at any position on the benzene ring where they are located; R8 and R9 are each independently selected from hydrogen or C1-C6 alkyl; In formulas (iii) and (iv), R 10 and R 11 respectively represent substituents at any position on the benzene ring where they are located; R 10 is selected from hydrogen or C1-C5 alkyl; R 11 is selected from hydrogen or C1-C3 alkyl.

9. The preparation method according to claim 8, characterized in that: In step (1), the alkyllithium is n-butyllithium; In step (2), react the spiro-containing compound shown in formula (i) with the compound shown in formula (ii) and the compound shown in formula (iii) in the presence of a palladium catalyst, a quaternary ammonium salt phase transfer catalyst and a phosphine ligand at 80 - 98 °C for 56 - 90 h; after the reaction is completed, add the compound shown in formula (iv) for capping to obtain a spiro-containing polymer shown in formula (I).

10. Use of the spiro-containing polymer according to any one of claims 1 - 7 in the preparation of an organic electroluminescent device.

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