JPH0134992B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel pentamethine thiopyrylium salt, namely 2,6-di-t-butyl-4-[3-
This invention relates to substituted-5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)pent-1,3-dienyl]thiopyrylium salt. It has been known that thiopyrylium and pyrylium dyes are used for various purposes. For example, it is used as an electron-accepting compound in direct positive photographic silver halide emulsions as disclosed in Japanese Patent Publication No. 46-40900, as well as U.S. Patent No. 3141700 by Davis et al. No. 3,250,615, U.S. Pat. No. 3,938,994 to Reynolds et al., and also Research Disclosure No. 16321, November 1977, No. 5.
It is useful as a spectral sensitizer for photoconductors, particularly for organic photoconductors, as described on page 1. Photoconductors sensitized with thiopyrylium and pyrylium dyes are used in a variety of applications, such as those disclosed in the above-mentioned patents, but they are particularly important for xerography and electrofax electrophotography. However, since such conventionally known thiopyrylium dyes have absorption bands in the visible range, when these thiopyrylium dyes are used as sensitizers for photoconductors, it is difficult to obtain transparent photoconductive compositions that exhibit absorption in the visible range. I couldn't do it. Therefore, an object of the present invention is to provide a new thiopyrylium compound that is colorless and transparent, has absorption in the far-infrared to near-infrared range, and has high sensitizing ability for photoconductive substances. The thiopyrylium salt of the present invention is 2,6-di-t-butyl-
4-[3-substituted-5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,
3-dienyl]thiopyrylium salt. In the formula, Z represents an anion, X is a halogen,
It is a lower alkyl group having 1 to 5 carbon atoms, a phenyl group, or a benzyl group. As the anion represented by Z, there are known single atomic ions having a negative charge or atomic group ions consisting of a plurality of atoms, and preferably from the viewpoint of synthesis.
An anion which is an acid represented by HZ and is a strong acid with a pKa of 5 or less, more preferably a pKa of 2 or less. Specific examples of anions include monatomic ions such as halogen anions, such as fluoride ions, chloride ions, bromide ions, and iodide ions. Examples of atomic group ions include organic anions such as trifluoroacetate ion, trichloroacetate ion, and p-toluenesulfonate ion, as well as perchlorate ion, periodate ion, tetrachloroaluminate ion, and trichloroferate ion ( ), tetrafluoroborate ion, hexafluorophosphate ion, sulfate ion, hydrogen sulfate ion, nitrate ion, and other inorganic anions. Among these, in the case of divalent anions, formally 1/2 of the anion is
It is interpreted to represent a monovalent anion. Among these anions, chloride ion, bromide ion, perchlorate ion, tetrafluoroborate ion, p-toluenesulfonate ion,
Trifluoroacetate ion is preferred. Examples of the halogen represented by X include fluorine, chlorine, bromine, and iodine, with chlorine and bromine being preferred. Examples of lower alkyl groups include methyl, ethyl, isopropyl, t-butyl and pentyl groups. Preferred thiopyrylium salts of the present invention are listed below, but the present invention is not limited to these compounds. The thiopyrylium salt of the present invention has its main absorption in the far-infrared to near-infrared region (near 650 to 900 nm) and does not substantially absorb visible light. If this salt is used as a sensitizing dye for an organic photoconductor that does not absorb visible light, such as poly-N-vinylcarbazole, a transparent photoreceptor can be produced. Therefore, even if a layer made of an organic photoconductor containing the thiopyrylium salt of the present invention is provided on white paper, the white paper can have the appearance of plain paper without a coating layer. The thiopyrylium salt of the present invention can be produced by the following method. [Production method 1] 1-phenylamino-2-substituted-3-phenylimide-1-propene compound ()] or compound () to 2,6-di-t-butyl-4-methylthiopyrylium salt [compound ()] A method of manufacturing by reacting a salt consisting of and an acid. In the formula, Z and X are the same groups as described above. Preferred specific examples of the compound () are 2-
Benzyl-1-phenylamino-3-phenylimide-1-propene, 2-phenyl-1-phenylamino-3-phenylimide-1-propene,
2-bromo- or 2-chloro-1-phenylamino-3-phenylimido-1-propene, 2-
Examples include ethyl-1-phenylamino-3-phenylimide-1-propene. Acids that form salts with compounds () are generally
Acids with a PKa of 4 or less, preferably 1 or less, such as hydrochloric acid, hydrobromic acid, sulfuric acid, and the like. The above reaction is carried out in carboxylic anhydride,
There are two ways to do it in an amine. In a method in which the reaction is carried out in a carboxylic anhydride, the carboxylic anhydride contributes to the reaction system as a deanilating agent. For example, acetic anhydride is used as the carboxylic anhydride. In order to dissolve the reaction raw materials in the carboxylic anhydride, an auxiliary solvent that does not react with the raw materials, catalyst, and products of the reaction system, such as acetic acid, nitrobenzene, etc., may be added. This reaction requires the presence of a base, and the base is generally an organic base such as an alkali metal salt of acetate such as sodium acetate or potassium acetate, or an alkyl amine, preferably a primary amine having 1 to 10 carbon atoms, with a total number of carbon atoms Secondary amines having 2 to 20 carbon atoms, tertiary amines having a total carbon number of 3 to 30, aromatic amines, and nitrogen-containing aromatic amines are used. Examples of these amines include triethylamine, piperidine, aniline, dimethylaniline, pyridine, and quinoline. The amount of the base is 0.2 to 100 mol, preferably 0.5 to 20 mol, per mol of 2,6-di-t-butyl-4-methyl-thiopyrylium salt. The amount of carboxylic acid anhydride is from 0.1 to 1 part of 2,6-di-t-butyl-4-methylthiopyrylium salt by weight.
100, preferably 1-50. In the method of carrying out the reaction in an amine, a co-solvent such as acetic acid or nitrobenzene may be added in the same manner as above. As the amine, the same ones as mentioned above are used. The amount of amine is 2,6-di-t-butyl-
Generally per mole of 4-methylthiopyrylium salt
The amount used is 0.5 to 200 mol, preferably 1 mol to 100 mol. The reaction of [Production method 1] is generally 50 to 200
It is preferably carried out at 80-140°C. Compound()
The amounts of and () may be chemical equivalents, but generally 2,
1-phenylamino-2-substituted per mole of 6-di-t-butyl-4-methylthiopyrylium salt
0.3 to 1 mole of 3-phenylimido-1-propene is used. The reaction time is generally 1 minute to 1 hour, although it depends on the temperature, type of solvent, etc. [Production method 2] Produced by reacting 2,6-di-t-butyl-4-methylthiopyrylium salt with 2-substituted-1,1,3,3-tetraalkoxypropane represented by the chemical structural formula () how to. Here, R represents a C ₁ -C ₄ alkyl group, and X represents the same group as defined in compound (). Examples of commonly used compounds () are 2
-Methyl- and 2-ethyl-1,1,3,3-
Tetramethoxypropane, 2-bromo- and 2
-Chloro-1,1,3,3-tetraethoxypropane, etc. The reaction is carried out in the presence of an amine in a carboxylic acid such as acetic acid or a carboxylic anhydride such as acetic anhydride. The amount of carboxylic acid or carboxylic acid anhydride is 0.1 to 100, preferably 1 to 50, per 1 of 2,6-di-t-butyl-4-methylthiopyrylium salt by weight. As the amine, the same one used in Production Method 1 can be used. The amount of amine is generally from 0.5 to 200 mol, preferably from 1 mol to 1 mol of 2,6-t-butyl-4-methylthiopyrylium salt.
100 moles used. Reaction temperature is generally 50-200℃
Preferably it is carried out at 80-140°C. The amounts of thiopyrylium salt and 2-substituted tetraalkoxypropane may be chemically equivalent, but generally the former is 1
0.5 to 10 mol of the latter is used. Although the reaction time depends on reaction conditions such as reaction temperature, it is generally 1.
It is from minutes to 1 hour. The compound () used in Production Methods 1 and 2 is, for example, 2,6-di-t-butyl-4H-pyran-4-
It can be synthesized from ion (compound (i)) through the following steps. That is, compound (i) is heated in the presence of phosphorus pentasulfide to obtain compound (ii) [step (1)], which is then heated under an inert gas stream.
Compound (iii) is obtained by reacting with an alkali sulfide such as sodium sulfide or an alkali hydrosulfide such as potassium hydrosulfide [step (2)]. Next, compound (iii) is hydrolyzed to directly obtain compound (v) [step (3)], or compound (iii) is reacted with a methylating agent to obtain compound (iv) [[step (3)′] Hydrolyze this to obtain compound (v) [Step (4)]. Compounds obtained in this way
Compound () is obtained by treating (v) with a Grignard reagent and then with an acid [Step (5)]. Compound (i) is described in "Journal of Heterocyclic Chemistry" No. 11 by Reynolds et al.
It can be synthesized by the method described in Vol., p. 1075 (1974). (Details about each of the above steps are described in the following publication by the present inventors. Step (1) and
(2): JP-A-56-7779, process (3): JP-A-56-7781
No. Publication, Process (3)': JP-A-56-7780, Process
(4): JP-A-56-7781, process (5): JP-A-55-
129283) The thiopyrylium salt of the present invention thus obtained can be used as a sensitizer for inorganic and organic photoconductive substances to improve the photoconductivity and sensitivity characteristics of various photoconductive substances. It will be done. Inorganic photoconductive substances include zinc oxide, but particularly effective photoconductive substances are organic photoconductive substances. Note that when the thiopyrylium salt of the present invention is used as a sensitizer for an inorganic photoconductive substance, it may not exhibit as sufficient a sensitizing effect as an organic photoconductive substance; Because the thiopyrylium salt of the present invention has a slightly smaller adsorption power for inorganic photoconductive substances such as zinc oxide than organic photoconductive substances, the presence of a third component such as a binder makes it less attractive to inorganic photoconductive substances. This is thought to be due to the desorption of thiopyrylium salt from the chemical substance. Therefore, in such cases, a binder made of a resin that does not contain polar groups (e.g., carboxyl groups, hydroxyl groups, etc.) that have a strong affinity for inorganic photoconductive substances (e.g., zinc oxide), If an electrophotographic photoreceptor is manufactured by dispersing a photoconductive substance, a sufficient sensitizing effect can be achieved. That is, for inorganic photoconductive substances such as zinc oxide, it is preferable to use a resin containing almost no polar groups, such as polystyrene, styrene-butadiene copolymer, etc., as the resin binder. Organic photoconductive substances preferably used in the present invention include low molecular weight compounds such as carbazoles such as carbazole and N-ethylcarbazole; triarylamines such as tri-p-tolylamine and triphenylamine; (In the formula, n is an integer of 2 to 4, m is an integer of 0 to 2, and R ₁ , R ₂ and R ₃ are hydrogen, methyl, ethyl,
Alkyl groups such as propyl, aryl groups such as phenyl and tolyl. ) Polyarylmethanes represented by: fused aromatic ring compounds such as anthracene; aromatic compounds with unsaturated bonds such as tetraphenylbutadiene and tetraphenylhexatriene; and oxadiazole,
thiadiazole, triazole, imidazole,
These include unsaturated heterocycle-containing compounds such as pyrazoline and its various derivatives, and polymer compounds such as poly-N-vinylcarbazole, brominated poly-N-vinylcarbazole, etc. Examples include vinylcarbazole derivatives; polyvinylanthracene; polyacenaphthylene; polyvinylacridine; polyvinylphenothiazine. Among these photoconductive materials are poly-N-vinylcarbazole; triarylamines such as tri-p-tolylamine and triphenylamine; 4,4'-bis(diethylamino)-2,2'-
Preferably used are polyarylmethanes such as dimethyltriphenylmethane; and unsaturated heterocycle-containing compounds represented by pyrazoline derivatives such as 3-(4-dimethylaminophenyl)-1,5-diphenyl-2-pyrazoline. It will be done. A photoconductive composition containing the thiopyrylium salt of the present invention as a sensitizer can be obtained by dispersing or dissolving these thiopyrylium dyes and a photoconductive substance in an organic solvent, and dispersing the composition on a conductive support. It can be coated by commonly used methods such as spin coating, blade coating, knife coating, reverse roll coating, dip coating, rod bar coating or spray coating and used as a photoreceptor after drying, or it can be mini-sprayed from the above organic solvent solution. Particles are manufactured using a device, etc., and a dispersion liquid in which the particles are dispersed in an insulating liquid is used for photoelectrophoresis. Conductive supports include paper; aluminum-paper laminates; metal foils such as aluminum foil and zinc foil; metal plates such as aluminum, copper, zinc, brass and galvanized plates; paper or cellulose acetate, polystyrene, etc. These include ordinary photographic film bases with metals such as chrome, silver, nickel, and aluminum deposited on them. Preferably, chromium, silver nickel, or
Vapor-deposited metals such as aluminum and indium oxide are used. Volatile hydrocarbon solvents with a boiling point of 200°C or lower are used as organic solvents, especially dichloromethane,
Preferred are halogenated hydrocarbons having 1 to 3 carbon atoms, such as chloroform, 1,2-dichloroethane, tetrachloroethane, dichloropropane or trichloroethane. Other aromatic hydrocarbons such as chlorobenzene, toluene, xylene or benzene, ketones such as acetone or 2-butanone,
Various solvents used in coating compositions and mixtures of the above solvents can also be used, such as ethers such as tetrahydrofuran and methylene chloride. The solvent is added in an amount of 1 to 100 g, preferably 5 to 20 g, per gram of the total amount of dye, photoconductive material and other additives. The amount of the sensitizer used in the present invention is 0.0001 to 30 parts by weight, preferably 0.001 to 10 parts by weight, per 100 parts by weight of the photoconductive substance. Production example of compound () which is a raw material compound (1) 2,6-di-t-butyl-4H-pyran-4
-Production of thione [compound (ii)]. 34.6 g of 2,6-di-t-butyl-4H-pyran-4-one was dissolved in 240 ml of anhydrous benzene, 73 g of phosphorus pentasulfide was added, and the mixture was heated under reflux for 2 hours and 30 minutes with stirring. After the reaction was completed, the benzene solution was removed by decanting, aqueous ammonia was added to the residue to decompose phosphorus pentasulfide, and the mixture was extracted with ether and dried using anhydrous sodium sulfate. The solvent of the benzene solution was distilled off under reduced pressure, and the residue was extracted with hexane and concentrated to obtain 16.0 g of reddish crystal compound (ii). The ether extract and the oil that was not extracted with hexane were combined and purified through a silica gel column using benzene to obtain an additional 6.8 g of crystals. (2) Production of 2,6-di-t-butyl-4H-thiopyran-4-thione [compound (iii)]. 6.64 g of compound (ii) was dissolved in 330 ml of HMPA (hexamethylphosphoric triamide) and argon gas was passed through the solution for 20 minutes. Heat and stir on an oil bath at 85 to 90°C, and add 19.8 g of sodium bisulfide (Wako Pure Chemical Industries, Ltd.) under an argon atmosphere.
About 70% NaSH.×H ₂ O (vacuum dried at 70-80° C. for 1 day over phosphorus pentasulfide) was added once for 30 minutes. After stirring at the same temperature for 1 hour and 30 minutes, the reaction solution was poured into water to complete the reaction. Filter the formed crystals,
Dry. Recrystallization from hexane gave compound (iii). Yield: 1.78g Yield: 25% (3) Method for producing 2,6-di-t-butyl-4-(methylthio)thiopyrylium iodide [compound (iv)]. 1.55 g of compound (iii) was heated under reflux for 1 hour with 20 ml of acetone and 5 ml of methyl iodide. After distilling off the solvent under reduced pressure, the residue was recrystallized from acetone to obtain 1.55 g of prismatic red crystals of compound (iv). Yield 63% (4) Method for producing 2,6-di-t-butyl-4H-thiopyran-4-one [compound (v)]. 1.30 g of 2,6-di-t-butyl-4-methylthio-thiopyrylium iodide was heated and stirred with 10 ml of dimethyl sulfoxide and 1 ml of water on an oil bath at 85-90° C. for 3 hours. After the reaction, the mixture was poured into water and extracted with diethyl ether. After drying the diethyl ether solution over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the residue was passed through an alumina column using a 1:1 (volume ratio) mixed solvent of benzene and diethyl ether, yielding 740 mg of the compound (v ) crystals were obtained. Yield 97%. Recrystallize from cyclohexane. (5) A method for producing 2,6-di-t-butyl-4-methylthiopyrylium perchlorate [compound ()]. The obtained 2,6-G-t- under an argon atmosphere
Butyl-4H-thiopyran-4-one (compound)
Dissolve 550 mg of methylmagnesium iodide in 20 ml of diethyl ether, and while cooling to about -10°C, add 8.6 ml of a diethyl ether solution (2.7 mmole) of methylmagnesium iodide.
was dripped. After the dropwise addition, stirring was continued for 45 minutes at room temperature (approximately 23°C), and then a saturated aqueous ammonium chloride solution was added. After the ether solution was decanted, the ether was distilled off under reduced pressure, and 20 ml of 35% perchloric acid was added to the residue and heated on a hot water bath to precipitate crystals. The crystals were filtered, washed with cold water and diethyl ether, and dried. Yield is 470
mg (yield 63%). Next, recrystallization from ethanol produces colorless crystals of 2,6-
Di-t-butyl-4-methylthiopyrylium perchlorate (compound) was obtained. Example 1 2,6-di-t-butyl-4-[3-benzyl-5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)-penta-1,3-dienyl] - Thiopyrylium perchlorate [compound
(4)] synthesis method according to [Production method 1]. 60 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 60 mg of 2-benzyl-1-phenylamino-3-phenylimide.
1-propene was heated in 1 ml of acetic anhydride on a 110°C water bath for 5 minutes. After heating, 60 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 100 mg of sodium acetate were added and heated for 10 minutes on an oil bath at 110°C. After cooling, 50 ml of diethyl ether was added and the precipitated crystals were filtered. Recrystallization from ethanol yielded 25 mg of crystals with a melting point of 221-222°C. Yield 20% Elemental analysis C ₃₈ H ₅₁ S ₂ ClO ₄ Calculated value C = 67.98% H = 7.66% S = 9.55% Actual value C = 68.05% H = 7.68% S = 9.30% Infrared absorption spectrum (wavenumber cm ^{- 1} ) 1482, 1180, 1135, 738, electronic spectrum (nm), in Katsuko: log ε ε is extinction coefficient (in acetonitrile) 803 (5.34), 742 (4.89), 442 (3.82), 364 (4.35)
，
310 (3.98) Example 2 2,6-di-t-butyl-4-[3-phenyl-5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3 -dienyl]-thiopyrylium perchlorate [compound
(3)] synthesis method according to [Production method 1]. 64 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 60 mg of 2-phenyl-1-phenylamino-3-phenylimide.
1-propene was heated in 1 ml of acetic anhydride on an oil bath at 110° C. for 5 minutes. After heating, 65 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 100 mg of sodium acetate were added and heated for 10 minutes on an oil bath at 110°C. After cooling, 50 ml of diethyl ether was added to precipitate crystals, which were filtered. When the crystals are recrystallized from ethanol, the melting point is 214 ~
30 mg of crystals at 215°C were obtained. Yield 23% Elemental analysis C ₃₇ H ₄₉ S ₂ ClO ₄ Calculated value C = 67.60% H = 7.51% S = 9.75% Actual value C = 67.49% H = 7.63% S = 9.50% Infrared absorption spectrum (wavenumber cm ^{- 1} ) 1480, 1160, 740 electronic spectrum (nm), in cutlet: log ε ε is extinction coefficient (in acetonitrile) 806 (5.32), 744 (4.88), 444 (3.79), 364 (4.39)
，
310 (3.97) Example 3 2,6-di-t-butyl-4-[3-methyl-
5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]
Synthesis method of thiopyrylium perchlorate [compound] according to [Production method 2]. 121 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 350 mg of 2-methyl-1,1,3,3-tetraethoxypropane were mixed in a mixed solvent of 1 ml of acetic acid and 1 ml of pyridine.
Heat on an oil bath at °C for 10 min. After cooling, 50 ml of diethyl ether was added, and the precipitated crystals were filtered and dried to obtain 100 mg of crystals.
Yield 45% Recrystallized from ethanol 53mg melting point 225-226
℃ crystals were obtained. Elemental analysis As C ₃₂ H ₄₇ S ₂ ClO ₄ Calculated value C = 64.56% H = 7.96% S = 10.77% Actual value C = 64.30% H = 7.88% S = 10.45% Infrared absorption spectrum (wavenumber cm ^-1 ) 1485, 1158, 740 Electronic spectrum (nm), in Katsuko: log ε ε is extinction coefficient (in acetonitrile) 809 (5.33), 744 (4.90), 446 (3.77), 360 (4.30)
，
311 (4.01) Example 4 2,6-di-t-butyl-4-[3-bromo-
5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]
A method for synthesizing thiopyrylium perchlorate [compound (6)] according to [manufacturing method 1]. 50 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 60 mg of 2-bromo-1-phenylamino-3-phenylimide-1
-propene was heated in 1 ml of acetic anhydride on an oil bath at 110°C for 5 minutes. After heating, 50 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 150 mg of sodium acetate were added and heated for 15 minutes on an oil bath at 110°C. After cooling, 50 ml of diethyl ether was added, and the precipitated crystals were filtered. Recrystallization from ethanol yielded 5 mg of crystals with a melting point of 224-225°C. Yield 3
% Elemental analysis Calculated value as C ₃₁ H ₄₄ S ₂ ClBrO ₄ C = 56.40% H = 6.72% S = 9.71% Actual value C = 56.51% H = 6.68% S = 9.55% Infrared absorption spectrum (wave number cm ^-1 ) 1485 , 1140, 740 Electronic spectrum (nm), in Katsuko: log ε ε is extinction coefficient (in acetonitrile) 804 (5.35), 746 (4.92), 438 (3.88), 356 (4.22)
，
308 (3.98) Example 5 2,6-di-t-butyl-4-[3-chloro-
5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]
A method for synthesizing thiopyrylium perchlorate [compound (5)] according to [manufacturing method 1]. 64 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 50 mg of 2-chloro-1-phenylamino-3-phenylimide-1
-propene was heated in 1 ml of acetic anhydride on an oil bath at 110°C for 5 minutes. After heating, 64 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 100 mg of sodium acetate were added and heated for 10 minutes on an oil bath at 110°C. After cooling, 50 ml of diethyl ether was added, and the precipitated crystals were filtered. Recrystallization from ethanol yielded 68 mg of crystals with a melting point of 224-226°C. Yield 55% Elemental analysis C ₃₁ H ₄₄ S ₂ Cl ₂ O ₄ Calculated value C = 60.47% H = 7.20% S = 10.41% Actual value C = 60.49% H = 7.31% S = 10.27% Infrared absorption spectrum (wave number cm ^-1 ) 1488, 1150, 743 Electron spectrum (nm), in cutlet: log ε ε is extinction coefficient (in acetonitrile) 806 (5.29), 746 (4.84), 438 (3.86), 360 (4.19)
，
310 (3.96) Example 6 2,6-di-t-butyl-4-[3-ethyl-
5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]
A method for synthesizing thiopyrylium perchlorate [compound (2)] according to [manufacturing method 1]. 61 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 50 mg of 2-ethyl-1-phenylamino-3-phenylimide-1
-propene was heated in 1 ml of acetic anhydride on an oil bath at 115°C for 5 minutes. After heating, 60 mg of 2,6-di-t-butyl-4-methylthiopyrylium perchlorate and 100 mg of sodium acetate were added and heated for 10 minutes on an oil bath at 115°C. After cooling, 50 ml of diethyl ether was added, and the precipitated crystals were filtered. Recrystallization from ethanol yielded 40 mg of crystals with a melting point of 239-240°C. Yield 35% Elemental analysis C ₃₃ H ₄₉ S ₂ ClO ₄ Calculated value C = 65.05% H = 8.11% S = 10.53% Actual value C = 65.33% H = 8.08% S = 10.65% Infrared absorption spectrum (wave number cm ^{- 1} ) 1488, 1170, 1060, 740 Electron spectrum (nm), in cutlet: log ε ε is extinction coefficient (in acetonitrile) 807 (5.30), 748 (4.87), 446 (3.78), 360 (4.28)
，
309 (3.99) Application example 1 1 g of poly-N-vinylcarbazole and 1.5 mg of compounds (1) to (6) shown in the table below are dissolved in 10 g of 1,2-dichloroethane, and a load bar is placed on an aluminum-deposited polyethylene terephthalate film. It was used and applied. A photoreceptor with a photoconductive layer was produced by drying at 55°C for one day. The thickness of the photoconductive layer is approximately 2 μm. Since this photoconductive layer is colorless and transparent to visible light, a photoreceptor in which this photoconductive layer is provided on an aluminum vapor-deposited layer may at first glance appear to be the aluminum vapor-deposited layer itself, even though the photoconductive layer is provided thereon. It has the appearance of something. For this photoreceptor, use a commercially available device to generate +6KV.
After corona discharge and charging to +400V, the surface is irradiated with light using a tungsten lamp at an illuminance of 5 lux to raise the surface potential.
The exposure amount was obtained by determining the time (seconds) it took for the voltage to reach 200V. The result was E1/2 = 25 lux seconds. 【table】

Claims (1)

[Claims] 1. 2,6-di- represented by the chemical structural formula ()
t-Butyl-4-[3-substituted-5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)
Penta-1,3-dienyl]thiopyrylium salt. Here, Z represents an anion, and X represents a halogen atom, a lower alkyl group having 1 to 5 carbon atoms, a phenyl group, or a benzyl group.