JPH0442428B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a novel dye not yet described in any literature, which has appropriate electron-withdrawing groups in the indolenine and benzothiazole cores as shown in the general formula below, and has a maximum absorption wavelength in the near-infrared region. . In the formula, R ₁ and R ₁ ' represent a nitro group, an alkylsulfonyl group or a cyano group. The alkylsulfonyl group suitably has 1 to 8 carbon atoms. X is

[Formula] or represents S, and Y is

[Formula] or represents S. R ₂ , R ₂ ′, R ₃ , and R ₃ ′ are the same or different alkyl groups, preferably having 1 to 6 carbon atoms.
R ₂ R ₃ and R ₂ ′R ₃ ′ may form a ring. R ₄ and R ₄ ' represent an alkyl group with or without substituents having 1 to 25 carbon atoms, and examples of the substituent include an alkoxy group, an alkoxycarbonyl group, a hydroxy group,
A sulfoxy group, an acyloxy group, and a phenyl group are preferred. A is −CH=CH−CH=,

【formula】

Selected from [formula], B is Halogens such as Cl, Br or

[Formula] is represented, and R ₅ and R ₆ represent an alkyl group or a phenyl group with or without a substituent. R ₅ and R ₆ may be the same or different, and the substituent for the phenyl group is preferably a halogen, an alkyl group, or an alkoxy group. represents an acid anion such as halogen, alkyl sulfate group, arylsulfonyl group, perchlorate, or tetrafluoroborate. Nuclear dyes are useful as electrophotography (for example, as a sensitizer for polyvinylcarbazole, in particular, they can be used in direct electrophotography to produce products without background coloration) or as filter dyes. . Various production methods conventionally known in this field can be applied to the production of the dye of the present invention. That is, dyes in which indolenine and benzothiazole nuclei are bonded with a straight-chain methine group can be produced by using pentadienedianyl or its salt, and those having a cycloalkane ring on the methyl chain can be produced by using pentadienedianyl or a salt thereof. It can be produced by using an intermediate having anilinomethylene groups at both ends. Next, an example will be given and explained. Example 1 1,3,3,1',3',3'-hexamethyl-5,
5′,-dinitroindotricarbocyanine perchlorate (dye No. 1) 2.6 g of 1,2,3,3-tetramethyl-5-nitroindolenium methosulfate, 1 g of pentadienedianyl, and 20 ml of acetic anhydride are heated on a hot water bath to precipitate crystals. Cool and collect to obtain 0.3 g of crude pigment. Dissolve this in 200 ml of methanol, add a hot aqueous solution of 0.4 g of sodium perchlorate, and boil for several minutes. The precipitated perchlorate of the dye is removed and washed with methanol to obtain 0.2 g of the dye.
Melting point over 290°, maximum absorption in methanol containing DMF 760nm. Example 2 1,1'-diethyl-3,3,3',3'-tetramethyl-5,5'-di(methylsulfonyl)-10,
12-ethylene-11-diphenylamino-indotricarbocyanine perchlorate (dye No. 2) 2.6 g of 1-ethyl-2,3,3-trimethyl-5-methylsulfonyl-indolenium ethosulfate, 2,5-dianilinomethylene-1-
Cyclopentylidene-N,N-diphenylammonium perchlorate A mixture of 1.8 g of acetic acid, 7 ml of acetic anhydride, and 1 g of potassium acetate was reacted by heating in a water bath for 20 minutes. After cooling the reaction mixture, it is treated with water and methanol to obtain 2.5 g of crude product. Recrystallization from methanol gives copper-colored platelet crystals with a melting point of 248°C. The maximum absorption wavelength in methanol is 780nm. Representative examples of dyes of the present invention synthesized in a similar manner are shown in Table 1.

[Table] As shown in this table, the maximum absorption wavelength of dyes in methanol is around 760 to 800 nm, and when these dyes are added to polyvinylcarbazole, the absorption wavelength shifts to longer wavelengths, resulting in almost no visible color. is not accepted. This is particularly advantageous in direct electrophotography. Next, the sensitizing effect of the dyes of the present invention on polyvinylcarbazole will be described. First, the photosensitive material was prepared by adding a 0.1% chloroform solution of the dye to an 8% polyvinylcarbazole solution dissolved in monochlorobenzene so that the dye concentration was 1.5 x 10 ^-6 mol per 1 g of polyvinylcarbazole. It was dispersed and applied to a thickness of about 200 μm on a PET film on which ITO electrodes had been vapor-deposited.
To measure the charging characteristics, a charging tester is used to measure the charging characteristics.
7 KV, 15 seconds, dark decay 5 seconds, light decay 50 lux (×27/7 rad), 20 seconds, cleaning exposure 20,000 Iux (×27/7 rad), 3 seconds, and from changes in surface potential, charge voltage, Table 2 shows the results of investigating the sensitivity (the amount of exposure required to reduce the surface potential to 1/2), the value of dark decay, and the magnitude of residual potential.

[Table] As shown in Table 2, the novel dyes of the present invention exhibited very excellent properties as sensitizers for polyvinylcarbazole. This is due to the sensitizing power of similar dyes (JP-A-Sho
48-54890), and together with the fact that almost no coloring is observed when a dye is added to polyvinylcarbazole as mentioned above, it has particularly favorable properties as a sensitizer for direct electrophotography. be. Furthermore, this dye has sharper absorption than general dyes, so it is also preferable as a filter dye.

Claims (1)

[Claims] 1. General formula (In the formula, X represents [formula] or S, Y represents [formula] or S. R ₁ , R ₁ ' represent a nitro group or an alkylsulfonyl group, R ₂ , R ₃ ,
R ₂ ′, R ₃ ′, R ₄ , and R ₄ ′ represent an alkyl group. A is selected from -CH=CH-CH= or [Formula], B represents [Formula], R ₅ and R ₆ represent a phenyl group, and represents an acid anion. ) cyanine dye.