CN101250406A - Heterofluorenyl polymer optoelectronic functional material and preparation method thereof - Google Patents

Abstract

The heterofluorenyl macromolecule photoelectric functional material and the preparation method thereof are a general method for preparing the heterofluorene and the macromolecule photoelectric material formed by replacing the carbon at the 9-position of fluorene with a heteroatom. Its molecular chain contains heterofluorene chain members and has the above structure, wherein R ₁ and R ₂ are phenyl, thienyl, pyridyl, and alkyl chains with a chain length of C1 to C18 (such as methyl, octadecyl, etc. ), or an oxygen substituent, or does not exist; _R is one of the adjacent para-substituents such as methyl, methoxy, alkoxy, tert-butyl; X is germanium, tin, boron, phosphorus, One of heteroatoms such as sulfur, indium, gallium, mercury, etc.; Ar is one of benzene ring, thiophene, pyrrole, pyridine, bipyridine, 9,9'-disubstituted fluorene, oxadiazole and their derivatives; m and n are the number of chain members of the polymer.

Description

Heterofluorenyl polymer optoelectronic functional material and preparation method thereof

technical field

The invention belongs to the technical field of photoelectric materials, and in particular relates to a general method for synthesizing heterofluorene and heterofluorene polymers formed after the carbon at the 9-position of fluorene is replaced by a heteroatom.

Background technique

At present, organic optoelectronic materials are mainly compounds with conjugated structures composed of carbon, hydrogen, oxygen, nitrogen, sulfur, etc. If heteroatoms, which are widely used in inorganic functional materials, are introduced into the organic conjugated system, it is very likely to obtain very good properties. Good organic-inorganic hybrid functional materials. Polyfluorene is a promising class of high-efficiency and stable polymer electroluminescent materials. Whether it is in the solution state or in the solid film state, polyfluorene polymers have shown excellent thermal stability and good luminescence. Efficiency, its light stability and thermal stability have been greatly superior to poly-p-phenylene vinylene (PPV), poly-p-phenylene vinylene (PPP), etc., which are also polymer electroluminescent materials. From a structural point of view, polyfluorene is formed by connecting two adjacent benzene rings with methylene. If heteroatoms are used to replace the carbon in this methylene group, that is, to connect biphenyls with heteroatoms so that the two benzene rings are in the same plane, the obtained polyheterofluorene is expected to have similar photoelectric properties to polyfluorene, and due to heteroatoms The unique interaction between atoms and the biphenyl skeleton leads to a unique electronic state structure, which may have unique photoelectric properties, and can be used in many fields such as batteries, photovoltaic cells, light-emitting diodes, nonlinear optics, and sensors.

Polycarbazole, which is widely used in electroluminescent materials and hole transport materials, can be regarded as polynitrofluorene in which the 9-position carbon is replaced by nitrogen. The extensive research and use of polynitrofluorene is because its monomer - dibromonitrofluorene - is easily brominated by nitrogen fluorene, but other heterofluorenes cannot be used in this way, because the general bromination (or iodine The method will destroy the heterofluorene molecule, so a new method different from the synthesis of dibromofluorene and dibromonitrofluorene must be adopted to synthesize dibromoheterofluorene. In 2002, Yamaguchi et al. synthesized 2,7-dibromobororene and found that its small molecule could detect fluorescence of fluoride ions, but they did not synthesize polybororene. In 2005, Holmes et al. synthesized polysilafluorene and found that the photoelectric performance of polysilafluorene is similar to that of polyfluorene, but its thermal stability is better than that of polyfluorene, which shows that the green band disappears in the fluorescence spectrum. The difficulty in the synthesis of polyheterofluorene is not only reflected in the difficult preparation of its monomers, but also in the need for special conditions for its polymerization. Except for polycarbazole and polysilafluorene, other polyheterofluorenes have not been reported yet.

Contents of the invention

Technical problem: the object of the present invention is to propose a polymer photoelectric functional material containing heterofluorene and its preparation method, which is a kind of 2,7-dibromoheterofluorene and its Preparation method, and a series of heterofluorene-based homopolymers and copolymers were prepared by the modified Suzuki polymerization method. The material covered in the present invention has excellent photoelectric properties, is a new type of high-efficiency polymer photoelectric material, and has good application prospects in the fields of electroluminescence, photovoltaic cells, nonlinear optics, sensors and the like.

Technical solution: The present invention synthesizes a series of 2,7-brominated heterofluorenes and their 2,7-boronated heterofluorenes, and uses an improved Suzuki polymerization method to synthesize a series of heterofluorene homopolymers and copolymer.

A series of heterofluorene-based conjugated polymers synthesized by the improved Suzuki polymerization method proposed by the present invention have the following molecular structures:

Among them, R ₁ and R ₂ are phenyl, thienyl, pyridyl, alkyl with a chain length of C1-C18 (such as methyl, octadecyl), or oxygen substituents, or do not exist; R ₃ is One of the ortho-para substituents such as methyl, methoxy, alkoxy, tert-butyl; X is one of the heteroatoms such as germanium, tin, boron, phosphorus, sulfur, indium, gallium, mercury, etc.; Ar is one of benzene ring, thiophene, pyrrole, pyridine, bipyridine, 9,9'-disubstituted fluorene, oxadiazole and their derivatives; m and n are the chain number of the polymer.

Above-mentioned polymer of the present invention, comparatively typical has following several kinds:

R ₁ and R ₂ are phenyl, R ₃ is methoxy, X is a germanium atom, Ar is 9,9'-dioctylfluorene, and its structural formula is:

Alternatively, R ₁ and R ₂ are methyl, R ₃ is octaneoxyl, X is a germanium atom, Ar is tin fluorene with the same substituent, and its structural formula is:

Alternatively, _R1 is a phenyl group, _R3 is an isobutyl group, X is a boron atom, Ar is a heterofluorene in which _R1 is a phenyl group, _R3 is an octaneoxyl group, and X is a phosphorus atom, and its structural formula is:

Alternatively, _R3 is a methyl group, X is a mercury atom, Ar is a heterofluorene in which _R1 is an octyl group, _R2 is an oxygen group, _R3 is an octaneoxyl group, and X is a phosphorus atom, and its structural formula is:

Alternatively, _R3 is octaneoxy, X is a sulfur atom, and Ar is a heterofluorene in which _R3 is octyloxy and X is a sulfur atom, and its structural formula is:

The synthetic method of the polymkeric substance that the present invention proposes is as follows:

(1) Synthesis of 2,7-dibromoheterofluorene monomer

Utilizing the characteristics that iodine is more active and selective than bromine when it reacts with butyllithium or magnesium, 3,3'-disubstituted-4,4'-dibromo-6,6'-diiodobiphenyl and butyl Lithium or magnesium react to generate 3,3'-disubstituted-4,4'-dibromo-6,6'-dilithium biphenyl or 3,3'-disubstituted-4,4'-dibromo-6, 6'-dimagnesium iodobiphenyl, the organometallic intermediate can be reacted with a suitable disubstituted heteroatom to obtain 2,7-dibromoheterofluorene monomer, such as dichlorosilane, dichlorogermane, dichlorotin Alkane and dichlorophosphine react to generate 2,7-dibromosilafluorene, germanium fluorene, tin fluorene, and phosphorene respectively; react with dimethoxyborane to generate 2,7-dibromobororene; react with sulfur dichloride The reaction generates 2,7-dibromothiofluorene; reacts with mercury dichloride, gallium dichloride, and indium bromide to generate corresponding 2,7-dibromomercurene, gallium fluorene, and indium fluorene.

(2) Synthesis of Ar monomer

After reacting with butyllithium or magnesium, the double-brominated Ar at both ends reacts with triisopropyl borate, and undergoes hydrolysis to obtain two sections of Ar groups with boric acid; further reflux reaction with propylene glycol in toluene solution to obtain Ar groups with borate esters at both ends;

Or, after reacting Ar with butyllithium or magnesium at both ends, and 2-isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaboron Heterocyclopentane (2-Isopropoxy-4, 4', 5, 5'-tetramethyl-1, 3, 2-dioxaboralane) was reacted to obtain an Ar group with boronic acid ester at both ends.

(3) Synthesis of polymers

Place the above-mentioned 2,7-dibromoheterofluorene monomer and two equimolar amounts of Ar groups with borate esters in toluene or tetrahydrofuran (THF), and use potassium carbonate (or sodium carbonate) and triphenylphosphine Palladium was used as a catalyst for Suzuki polymerization, and the resulting product was subjected to multiple precipitation with methanol and Soxhlet extraction with acetone to obtain a conjugated polymer of heterofluorene and Ar groups;

Alternatively, the above-mentioned 2,7-dibromoheterofluorene monomer and two equimolar amounts of Ar groups with borate esters are placed in toluene or tetrahydrofuran (THF), and tetraethylammonium hydroxide, tricyclohexyl Alkylphosphine and palladium acetate were used as catalysts for Suzuki polymerization, and the resulting product was subjected to multiple precipitation with methanol and Soxhlet extraction with acetone to obtain a conjugated polymer of heterofluorene and Ar groups;

Alternatively, the above-mentioned 2,7-dibromoheterofluorene monomer and two equimolar amounts of Ar groups with borate esters are placed in toluene or tetrahydrofuran (THF), and potassium phosphate, tri-tert-butylphosphine and Pd ₂ (dba) ₃ was used as a catalyst for Suzuki polymerization, and the resulting product was subjected to multiple precipitation with methanol and Soxhlet extraction with acetone to obtain a conjugated polymer of heterofluorene and Ar groups.

The molecular weight of the polymer obtained above is between 5,000 and 300,000, and the molecular weight distribution is below 2.0.

Detailed ways

The technical solutions of the present invention are further described below through examples, so as to better understand the contents of the present invention.

The heterofluorene-containing macromolecule photoelectric functional material of the present invention is characterized in that its molecular chain contains heterofluorene chains, and has the following structure:

Wherein, R ₁ and R ₂ are phenyl, thienyl, pyridyl, alkyl with a chain length of C1-C18 (such as methyl, octadecyl, etc.), or are oxygen substituents, or do not exist;

_R is one of the adjacent para-substituents such as methyl, methoxy, alkoxy, tert-butyl;

X is one of germanium, tin, boron, phosphorus, sulfur, indium, gallium, mercury and other heteroatoms;

Ar is one of benzene ring, thiophene, pyrrole, pyridine, bipyridine, 9,9'-disubstituted fluorene, oxadiazole and their derivatives;

m and n are the number of chain members of the polymer.

Example 1:

Synthesis of poly[(3,6-dimethoxy-9,9'-diphenyl-9-germanofluorene)-co-alt-(9,9'-dioctylfluorene)]

After 4,4'-dibromo-6,6'-diiodo-3,3'-dimethoxybiphenyl (1) was reacted with n-butyl lithium at -100°C for half an hour, dichlorodiphenyl base germane, reacted overnight at room temperature, extracted with ether, and obtained white solid 2,7-dibromo-3,6-dimethoxy-9,9'-diphenyl-9-germanefluorene after column separation ( Abbreviated as A1), the purity is greater than 99% after recrystallization several times. 9,9'-dioctylfluorene-2,7-bis(trimethylene borate) (abbreviated as B1) was synthesized by the method reported in the literature.

Equivalent monomers A1 and B1, and 1 mol% triphenylphosphopalladium (Pd(PPh ₃ ) ₄ ) were dissolved in anhydrous toluene under the protection of an inert gas. Deaerated 2M aqueous potassium carbonate solution (3 equiv.) was then added. The reaction system was heated to 90°C, and after maintaining the reaction for 3 days, the reaction was capped with excess benzene bromide and benzene borate for 6 hours each. After the reaction was completed, it was cooled to room temperature, the reaction solution was dropped into methanol and water (5/1), and the resulting precipitate was collected. The precipitate was washed with methanol, then washed with acetone in a Soxhlet extractor for 3 days to remove oligomers and excess catalyst, and dried in vacuum to obtain a polymer.

Example 2:

Poly[(3,6-dioctyloxy-9,9'-dimethyl-9-germanofluorene)-co-alt-(3,6-dioctyloxy-9,9'-dimethyl- 9-Tinfluorene)] Synthesis

After 4,4'-dibromo-6,6'-diiodo-3,3'-dioctyloxybiphenyl (2) was reacted with n-butyllithium at -100°C for half an hour, dichlorodimethyl Genylgermane, slowly raised to normal temperature to react overnight, extracted with ether, and separated by column to obtain white solid 2,7-dibromo-3,6-dioctyloxy-9,9'-dimethyl-9- Germanium fluorene (abbreviated as A2), the purity of germanium fluorene is greater than 99% after several times of recrystallization.

After 4,4'-dibromo-6,6'-diiodo-3,3'-dioctyloxybiphenyl (2) was reacted with n-butyllithium at -100°C for half an hour, dichlorodimethyl Stannane, slowly raised to normal temperature to react overnight, extracted with ether, and separated by column to obtain white solid 2,7-dibromo-3,6-dioctyloxy-9,9'-dimethyl-9- Tin fluorene (abbreviated as B2), the purity is greater than 99% after several times of recrystallization. After B2 reacted with n-butyllithium at -78°C for half an hour, add 2-isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaborolane Alkane (2-Isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaboralane), slowly raised to room temperature to react overnight, extracted with ether, and obtained white solid 2,7- Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-)-3,6-dioctyloxy-9,9'-dimethyl- 9-Tinfluorene (abbreviated as B2'), the purity is greater than 99% after several times of recrystallization.

Dissolve equal amounts of A2 and B2', 2 mol% palladium acetate, 8 mol% tricyclohexylphosphine in toluene under nitrogen, stir at 90°C for 5 minutes, then add 20% by weight of degassed Tetraethylammonium hydroxide aqueous solution (5-20 equivalents), stirred at 90°C for 2 hours, then reacted with excess benzene bromide and boric acid benzene for 2 hours each. After the reaction is completed, cool to room temperature, drop the reaction solution into methanol and water (5-10/1), and collect the resulting precipitate. The precipitate was washed with methanol, then washed with acetone in a Soxhlet extractor for 3 days to remove oligomers and excess catalyst, and dried in vacuum to obtain a polymer.

Example 3:

Synthesis of poly[(3,6-dimethyl-9-mercurene)-co-alt-(3,6-dioctyloxy-9-octyl-9-phosphorene oxide)]

4,4'-dibromo-6,6'-diiodo-3,3'-dimethylbiphenyl (3) reacted with n-butyllithium at -100°C for half an hour, then added mercury dichloride, Slowly rise to room temperature and react overnight, extract with ether, and obtain solid 2,7-dibromo-3,6-dimethyl-9-mercurene (abbreviated as A3) after column separation, and make it pure after several recrystallizations. Greater than 99%.

After 4,4'-dibromo-6,6'-diiodo-3,3'-dioctyloxybiphenyl (2) in Example 2 was reacted with n-butyllithium at -100°C for half an hour, Add dichlorooctyl phosphine oxide, slowly rise to room temperature and react overnight, extract with ether, and obtain solid 2,7-dibromo-3,6-dioctyloxy-9-octyl-9-oxidation after column separation Phosphorene (abbreviated as B3), the purity is greater than 99% after several times of recrystallization. After B3 reacted with n-butyllithium at -78°C for half an hour, add 2-isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaborolane Alkane (2-Isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaboralane), slowly raised to normal temperature to react overnight, extracted with ether, and obtained white solid 2,7- Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-)-3,6-dioctyloxy-9-octyl-9-phosphine oxide Fluorene (abbreviated as B3'), the purity is greater than 99% after several times of recrystallization.

Dissolve equivalent amounts of A3 and B3', 2.5 mol% of Pd ₂ (dba) ₃ , 10 mol% of tri-tert-butylphosphine, and potassium phosphate (3 equivalents) in tetrahydrofuran (THF) under nitrogen, and stir for 20 After 1 hour, the reaction was capped with excess benzene bromide and benzene borate for 6 hours each. After the reaction is completed, cool to room temperature, drop the reaction solution into methanol and water (5-10/1), and collect the resulting precipitate. The precipitate was washed with methanol, then washed with acetone in a Soxhlet extractor for 3 days to remove oligomers and excess catalyst, and dried in vacuum to obtain a polymer.

Example 4:

Synthesis of poly[3,6-dioctyloxy-9-thiofluorene]

After 4,4'-dibromo-6,6'-diiodo-3,3'-dioctyloxybiphenyl (2) in Example 2 was reacted with n-butyllithium at -100°C for half an hour, Add sulfur dichloride, react at room temperature overnight, extract with ether, and obtain white solid 2,7-dibromo-3,6-dioctyloxy-9-thiofluorene (abbreviated as A4) after column separation.

After A4 reacted with n-butyllithium at -78°C for half an hour, add 2-isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaborolane Alkane (2-Isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaboralane), slowly raised to room temperature to react overnight, extracted with ether, and obtained white solid 2,7- Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-)-3,6-dioctyloxy-9-thiofluorene (B4 for short), The purity was greater than 99% after several recrystallizations.

Dissolve equal amounts of A4 and B4, 2.5 mol% of Pd ₂ (dba) ₃ , 10 mol% of tri-tert-butylphosphine, and potassium phosphate (3 equivalents) in tetrahydrofuran (THF) under nitrogen, and stir for 20 hours After that, use excess benzene bromide and boric acid benzene capping reaction for 6 hours each. After the reaction is completed, cool to room temperature, drop the reaction solution into methanol and water (5-10/1), and collect the resulting precipitate. The precipitate was washed with methanol, then washed with acetone in a Soxhlet extractor for 3 days to remove oligomers and excess catalyst, and dried in vacuum to obtain a polymer.

Claims (7)

1. A heterofluorenyl macromolecule photoelectric functional material, characterized in that its molecular chain contains heterofluorene chains, and has the following structure:

Wherein, R ₁ and R ₂ are phenyl, thienyl, pyridyl, alkyl with a chain length of C1-C18, or are oxygen substituents, or do not exist; _R is one of the adjacent para-substituents such as methyl, methoxy, alkoxy, tert-butyl; X is one of germanium, tin, boron, phosphorus, sulfur, indium, gallium, mercury and other heteroatoms; Ar is one of benzene ring, thiophene, pyrrole, pyridine, bipyridine, 9,9'-disubstituted fluorene, oxadiazole and their derivatives; m and n are the number of chain members of the polymer. 2. The polymer photoelectric functional material containing heterofluorene according to claim 1, characterized in that: R ₁ and R ₂ are phenyl, R ₃ is methoxy, X is a germanium atom, and Ar is 9,9' -Dioctylfluorene, whose structural formula is:

3. the macromolecule photoelectric functional material containing heterofluorene according to claim 1, is characterized in that: R ₁ , R ₂ are methyl groups, R ₃ are octyloxy groups, X is a germanium atom, and Ar is the same substituent Tin fluorene, its structural formula is:

4. the macromolecule photoelectric functional material containing heterofluorene according to claim 1, is characterized in that: R ₁ is phenyl, R ₃ is isobutyl, X is a boron atom, Ar is that R ₁ is phenyl R ₃ Be the heterofluorene that octyloxyl X is phosphorus atom, its structural formula is:

5. the macromolecule photoelectric functional material containing heterofluorene according to claim 1, is characterized in that: R ₃ is a methyl group, X is a mercury atom, Ar is R ₁ is an octyl group R ₂ is an oxygen group R ₃ is an octyl group The oxygen group X is a heterofluorene of a phosphorus atom, and its structural formula is:

6. the macromolecule photoelectric functional material containing heterofluorene according to claim 1, is characterized in that: _R3 is octyloxy group, X is a sulfur atom, and Ar is the heterofluorene that _R3 is octoxyl group X is a sulfur atom , whose structure is:

7. A preparation method of a polymer photoelectric functional material containing heterofluorene as claimed in claim 1, characterized in that the specific synthesis steps are as follows: Step 1: Synthesis of 2,7-dibromoheterofluorene monomer Utilizing the characteristics that iodine is more active and selective than bromine when it reacts with butyllithium or magnesium, 3,3'-disubstituted-4,4'-dibromo-6,6'-diiodobiphenyl and butyl Lithium or magnesium react to generate 3,3'-disubstituted-4,4'-dibromo-6,6'-dilithium biphenyl or 3,3'-disubstituted-4,4'-dibromo-6, 6'-dimagnesium iodobiphenyl, the organometallic intermediate can be reacted with a suitable disubstituted heteroatom to obtain 2,7-dibromoheterofluorene monomer; Step 2: Synthesis of Ar monomer After reacting with butyllithium or magnesium, the double-brominated Ar at both ends reacts with triisopropyl borate, and after hydrolysis, two sections of Ar groups with boronic acid are obtained, which are further reacted with propylene glycol in toluene solution to obtain Ar groups with borate esters at both ends; or, Ar groups with dibromo at both ends react with butyllithium or magnesium, and 2-isopropoxy-4,4',5,5'-tetramethyl Base-1,3,2-dioxaborolane "2-Isopropoxy-4,4',5,5'-tetramethyl-1,3,2-dioxaboralane" reaction to obtain boronic acid ester with both ends Ar group; Step 3: Polymer Synthesis Put the above-mentioned 2,7-dibromoheterofluorene monomer and two equimolar amounts of Ar groups with borate esters in toluene and tetrahydrofuran solvents, and carry out Suzuki with potassium carbonate or sodium carbonate and triphenylphosphopalladium catalysts. Polymerization reaction, the resulting product undergoes multiple precipitations with methanol and Soxhlet extraction with acetone to obtain a conjugated polymer of heterofluorene and Ar groups; or, combine the above-mentioned 2,7-dibromoheterofluorene monomer with two segments The Ar group with borate ester is placed in toluene and tetrahydrofuran solvent, and tetraethylammonium hydroxide, tricyclohexylphosphine and palladium acetate are used as catalysts for Suzuki polymerization. The resulting product is subjected to multiple precipitations with methanol and acetone extraction to obtain a conjugated polymer of heterofluorene and Ar groups; or, place the above-mentioned 2,7-dibromoheterofluorene monomer and two equimolar amounts of Ar groups with borate esters in toluene, tetrahydrofuran In the solvent, potassium phosphate, tri-tert-butylphosphine and _Pd2 (dba) ₃ were used as catalysts for Suzuki polymerization, and the resulting product was subjected to multiple precipitations with methanol and Soxhlet extraction with acetone to obtain conjugated polymerization of heterofluorenes and Ar groups things.