JPH032174B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel condensation product of N-substituted-3,6-dihalocarbazole and diethynylbenzene and a method for producing the same.

A large number of compounds have been known as organic photoconductive materials, and the representative compound is poly-N-
It is vinyl carbazole.

Although this organic photoconductive material has various advantages over inorganic photoconductive materials such as selenium, it also has disadvantages, and one of its major disadvantages is low sensitivity. Therefore, the present inventors conducted various studies for the purpose of finding a compound having excellent properties as an organic photoconductive material. As a result, they have discovered a condensation product of N-substituted-3,6-dihalocarbazole and diethynylbenzene that has excellent photoconductivity.

The condensation product of N-substituted-3,6-dihalocarbazole and diethynylbenzene of the present invention is a compound having the following general formula () and having an average degree of polymerization of 5 or more.

(However, R is an alkyl group having 1 to 16 carbon atoms,
Cycloalkyl group or aralkyl group, n is a positive integer. ) This compound () has the general formula () (However, R is an alkyl group having 1 to 16 carbon atoms,
Cycloalkyl group or aralkyl group, X is the same or different bromine or iodine. ) N-substituted-3,6-dihalocarbazole represented by the general formula () It is produced by reacting diethynylbenzene shown in This reaction typically requires a catalyst and a hydrogen halide scavenger. As a catalyst, a combination of a noble metal compound such as palladium acetate and a phosphorus compound such as triarylphosphine is suitable. As hydrogen halide scavengers, secondary amines,
Amines such as tertiary amines and basic salts such as sodium bicarbonate and sodium carbonate are suitable.

The N-substituted dihalocarbazole, which is the raw material compound of the present invention, can be prepared by halogenating the carbazole with bromine or iodine chloride and then introducing a substituent, or by introducing a substituent or
Substituted carbazoles can be prepared by halogenation with bromine or iodine chloride. The thus obtained N-substituted-3,6-dihalocarbazole represented by the general formula () and diethynylbenzene represented by the general formula () are mixed in the presence of, for example, palladium acetate, triarylphosphine, and a tertiary amine. 75~
React at a temperature of 150°C.

Triarylphosphines include triphenylphosphine, tri-o-tolylphosphine, tris(2,5-diisopropylphenyl)phosphine, tri-α-naphthylphosphine, tris(2,3,4,5- Tetramethylphenyl)phosphine, tris(5-trifluoromethyl-2-
Mention may be made of phosphines such as methylphenyl)phosphine, tris(2-methyl-5-t-butylphenyl)phosphine, tris(P-carbomethoxyphenyl)phosphine, in particular tri-o-tolylphosphine, tris(2 -Methyl-5-tert-butylphenyl)phosphine is preferably used. The triarylphosphine used in the present invention is suitably used in an amount of 0.5 to 10 mol % based on 1 mol of palladium acetate. In addition, the amount of palladium acetate used is 0.5 to 4 mol% of the amount of diethynylbenzene used.
is appropriate.

Secondary amines and tertiary amines are used as scavengers for generated hydrogen halides, such as diethylamine, di-n-butylamine, piperidine, morpholine, triethylamine, tri-n-butylamine, triamylamine, and tetramethylethylenediamine. Any common amine may be used, and the amount used is slightly in excess of the equivalent molar amount of hydrogen halide generated.

Common reaction solvents such as N,
N-dimethylformamide, dimethylacetamide, toluene, xylene, chlorobenzene, O-
Dichlorobenzene, trichlorobenzene, N-methyl-2-pyrrolidone, dimethylacetamide,
Dimethyl sulfoxide, acetonitrile, etc. may be used.

N-substituted dihalocarbazole () and diethynylbenzene () may each be used in combination of two or more types, but it is particularly preferable to use P-diethynylbenzene as diethynylbenzene (). On the other hand, as the N-substituted dihalocarbazole, a dihalocarbazole having an alkyl chain having 2 to 12 carbon atoms is preferred from the viewpoint of product solubility and performance. Both end groups of the resulting polymer () are usually hydrogen, bromine or iodine, especially the end group on the ethynyl group side is usually hydrogen. Further, the polymer can be obtained as a mixture of compounds having a degree of polymerization of 2 or more. The average degree of polymerization is preferably 5 or more, particularly 10 or more.

The compound obtained by the method of the present invention has useful properties such as heat resistance and conductivity, and can be used for any purpose, but is particularly useful as a photoconductive substance, and is It has superior photoconductivity compared to poly-N-vinylcarbazole, which is a typical photoconductive material.

This photoconductive substance is used in electrophotographic photoreceptors, image forming elements, etc. like conventional poly-N-vinylcarbazole, but when used as an electrophotographic photoreceptor, it is used as a general organic photoconductive substance. It can be similarly sensitized. One type of sensitizer is an electron acceptor represented by 2,4,7-trinitrofluorene-9one, which uses a photoconductive substance as an electron donor and forms a charge transfer complex with it. The other one is crystal violet, a dye represented by rhodamine 6G. In addition, in recent years, highly sensitive electrophotographic photoreceptors that combine a charge generating substance and a charge transporting substance have been proposed, and the compound obtained by the present invention is a useful charge transporting substance. As the charge generating substance used in this case, for example, inorganic pigments such as selenium, selenium-tellurium, cadmium sulfide, and zinc sulfide, organic pigments, charge transfer complexes, and mixtures thereof can be appropriately selected and used.

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples.

Example 1 33.44 parts (by weight, same hereinafter) of carbazole is added to 500 parts of carbon disulfide, and the mixture is heated and dissolved until the carbon disulfide refluxes. While stirring, 72 parts of bromine dissolved in 40 parts of carbon disulfide were added dropwise. After aging under reflux for 1 hour, it is cooled. After washing the precipitate with carbon disulfide, it was thoroughly washed with water. Purified by recrystallization from ethyl alcohol, melting point 213℃
37.06 parts of 3,6-dibromocarbazole (hereinafter abbreviated as DBCZ) was obtained as white needle-like crystals.

9.75 parts of DBCZ to N,N-dimethylformamide
After dissolving in 20 parts, 2.18 parts of powdered caustic potassium was added.
After adding 8.22 parts of n-dodecyl bromide at room temperature, the mixture was reacted at 60°C for 4 hours. After cooling, the reaction mixture was poured into 300 parts of water. After thoroughly washing the precipitate with water and recrystallizing it with ethanol, N-n-dodecyl-3,
12.43 parts of 6-dibromocarbazole was obtained.

N-n-dodecyl-3,6-dibromocarbazole 1.97 parts, P-diethynylbenzene 0.505 parts,
A mixed portion consisting of 1.36 parts of piperidine, 0.018 parts of palladium acetate, 0.049 parts of tri-o-tolylphosphine, and 5 parts of xylene was reacted at 100° C. for 2.5 hours with stirring under a nitrogen atmosphere. The reaction mixture was filtered while it was hot to remove insoluble materials, and then poured into methanol and reprecipitated to obtain 1.00 parts of a yellow polymer.

In the IR chart of a polymer, ν(C≡H) due to the polymer terminal is observed only as a small absorption, and the absorption based on ν(C≡C) is 2200 cm ^-1
What is observed is It shows the formation of polymer. The NMR spectrum of the polymer also indicates the above structure.

The number average molecular weight was determined by GPC and was 1500.
It was hot.

The IR chart is shown in Figure 1, and the NMR spectrum is shown in Figure 2.

Example 2 A polymer having the following structure was obtained according to the method of Example 1, except that i-amyl bromide was used instead of n-dodecyl bromide. The resulting polymer is insoluble in common organic solvents.

[Brief explanation of the drawing]

FIG. 1 shows an IR chart of the carbazole derivative of the present invention prepared according to Example 1, and FIG. 2 shows an NMR spectrum.

Claims (1)

[Claims] 1. General formula (However, R is an alkyl group having 1 to 16 carbon atoms,
Cycloalkyl group or aralkyl group, n is a positive integer. ) A carbazole derivative having an average degree of polymerization of 5 or more. 2 General formula (However, R is an alkyl group having 1 to 16 carbon atoms,
Cycloalkyl group or aralkyl group, X is the same or different bromine or iodine. A general formula characterized by reacting an N-substituted-3,6-dihalocarbazole represented by (However, R is an alkyl group having 1 to 16 carbon atoms,
Cycloalkyl group or aralkyl group, n is a positive integer. ) A method for producing a polycondensation product of N-substituted-3,6 dihalocarbazole and diethynylbenzene. 3. The method of claim 2, wherein the catalyst comprises a combination of palladium acetate and triarylphosphine. 4 The hydrogen halide scavenger is a secondary amine or
3. The method according to claim 2, wherein the amine is a grade amine.