JPH0341821B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to photoconductive compositions, particularly photoconductive compositions that are transparent to visible light. It has been known that thiopyrylium and pyrylium dyes are used for various purposes. For example, as disclosed in Japanese Patent Publication No. 46-40900, it is used directly as an electron-accepting compound in positive photographic silver halide emulsions.
U.S. Pat. No. 3,141,700 to VanAllan et al., U.S. Pat. No. 3,250,615 to vanAllan et al., and U.S. Pat. Fifth
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, it is an object of the present invention to provide a photoconductive composition comprising a photoconductive material containing a novel thiopyrylium compound as a sensitizer, which imparts a high sensitizing ability to a photoconductor. The thiopyrylium salt used in 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, and X represents hydrogen, halogen, an alkyl group, or an aryl group. ) The anion represented by Z includes 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, brocade 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, alpha 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 1
It is interpreted as representing a valent anion. Among these anions, chloride ion, bromide ion,
Perchlorate ion, tetrafluoroborate ion, p-toluenesulfonate ion, and trifluoroacetate ion are preferred. Examples of the halogen represented by X include fluorine, chlorine, bromine, and iodine, with chlorine and bromine being preferred. Alkyl group has 1 carbon number
~15, preferably 1 to 5, e.g. methyl groups,
In addition to straight chain or branched alkyl groups such as ethyl group, isopropyl group, t-butyl group and pentyl group, straight chain or branched alkyl groups having substituents are also included. Examples of this substituent include aryl groups having 6 to 15 carbon atoms, preferably 6 to 13 carbon atoms, such as phenyl, tolyl, ethyl phenyl, and naphthyl groups; halogens such as chlorine and bromine;
5, preferably 1 to 3 alkoxy groups, such as methoxy groups. Specific examples of alkyl groups having aryl substituents include benzyl group, (4-methylphenyl)methyl group, (2-methylphenyl)methyl group, phenethyl group, (1-methylphenyl)methyl group,
naphthyl) methyl group, etc. The aryl group has 6 carbon atoms and has a substituent other than the phenyl group.
-11, preferably 6-8 aryl groups are also included. Examples of this substituent include halogens such as chlorine and bromine; alkoxy groups having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, such as methoxy groups; and 1 to 1 carbon atoms.
-5, preferably 1-3 alkyl groups. Specific examples of aryl groups include phenyl group, o, m, p-tolyl group, 2,3-, 2,
Examples include 4- and 2,5-xylyl groups and ethyl phenyl groups. Preferred thiopyrylium salts used in the present invention are listed below, but the present invention is not limited to these compounds. The thiopyrylium salt used in the present invention has its main absorption in the far-infrared to near-infrared region (around 650 to 900 nm) and does not substantially absorb visible light. This salt is poly-
When used as a sensitizing dye for an organic photoconductor that does not absorb visible light, such as N-vinylcarbazole, a colorless and transparent photoreceptor can be produced. Therefore, even if a layer made of an organic photoconductor containing a thiopyrylium salt used in the present invention is provided on white paper, the white paper can have the appearance of plain paper without a coating layer. The photoreceptor made of an organic photoconductive substance containing a thiopyrylium salt used in the present invention is used in ordinary electrophotography using tungsten light as a light source, and is sensitive to far-infrared to near-infrared, so it can be used in this region. It is particularly effective in electrophotography using a light source (for example, a semiconductor laser).
In addition, the thiopyrylium salt used in the present invention can be incorporated into photoconductive photosensitive particles in photoelectrophoresis electrophotography and used effectively as photoconductive photosensitive particles. Further, one of the excellent characteristics of the compound of the present invention is that the photoreceptor using the compound used in the present invention has high sensitivity. The thiopyrylium salt used in the present invention can generally be produced by the following method. [Production method 1] 1-phenylamino-2-substituted-3-phenylimido-1-propene [compound ()] or compound ( ) and an acid salt. 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-phenylimido-1-propene, 2-phenyl-1-phenylamino-3-phenylimido-1-propene,
2-bromo or 2-chloro-1-phenylamino-3-phenylimido-1-propene, 2-
Examples include ethyl-1-phenylamino-3-phenylimido-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 a carbon number of 1 to 10, with a total number of carbon atoms of 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-methylthiopyrylium salt. The amount of carboxylic 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 in parentheses and () may be chemical equivalents, but 2,
6-di-t-butyl-methylthiopyrylium salt 1
1-phenylamino-2-substituted-3- per mole
From 0.3 to 1 mol of phenyl imido-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 (). Commonly used examples of compounds () include 2-methyl- and 2-ethyl-1,1,3,
Examples include 3-tetramethoxypropane, 2-bromo- and 2-chloro-1,1,3,3-tetraethoxypropane. 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 2,6-di-t
It is generally used in an amount of 0.5 to 200 mol, preferably 1 mol to 100 mol, per mol of -butyl-4-methylthiopyrylium salt. Reaction temperature is generally 50-200℃
It is preferably carried out at a temperature of 80 to 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 on (compound ()) through the following steps. That is, compound () is heated in the presence of phosphorus pentasulfide to obtain compound () [step (1)], which is then heated under an inert gas stream with an alkali sulfide such as sodium sulfide,
Alternatively, the compound () is obtained by reacting with an alkali hydrosulfide such as potassium hydrosulfide [Step (2)]. Next, compound () is hydrolyzed to obtain compound () directly [step (3)], or compound () is reacted with a methylating agent to obtain compound () [step (3)']
This is hydrolyzed to obtain the compound () [Step
(Four)〕. Compound () thus obtained is treated with a Grignard reagent and then treated to obtain compound () [Step (5)]. The compound () 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-
Publication No. 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. . 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, the inorganic photoconductive substance (e.g. zinc oxide) is mixed with 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 the inorganic photoconductive substance (e.g. zinc oxide). If an electrophotographic photoreceptor is manufactured by dispersing a conductive 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,
R ₁ , R ₂ and R ₃ are hydrogen, alkyl groups such as methyl, ethyl and propyl, and aryl groups such as phenyl and tolyl. ); fused aromatic ring compounds such as anthracene; aromatic compounds with unsaturated bonds such as tetraphenylbutadiene and tetraphenylhexatriene; and oxadiazole, thiadiazole, triazole, imidazole , pyrazoline and various derivatives thereof, and other unsaturated heterocycle-containing compounds, and examples of polymer compounds include poly-N-vinylcarbazole,
Examples include poly-N-vinylcarbazole derivatives such as brominated poly-N-vinylcarbazole; polyvinylanthracene; polyacenaphthylene; polyvinylacridine; polydinylphenothiazine. Among these photoconductive materials are poly-N-vinylcarbazole; triarylamines such as tri-p-tolylamine and triphenylamine; 4,4'-bis(diethylamino)-2,2'-
Unsaturated heterocycle-containing compounds represented by polyarylmethane such as dimethyltriphenylmethane; and pyrazoline derivatives such as 3-(4-dimethylaminophenyl)-1,5-diphenyl-2-pyrazoline are preferably used. It will be done. The photoconductive composition of the present invention containing the above-mentioned thiopyrylium salt as a sensitizer can be obtained by dispersing or dissolving these thiopyrylium dyes and a photoconductive substance in an organic solvent. It can be coated on the body by a commonly used method such as spin coating, blade coating, knife coating, reverse roll coating, dip coating, rod bar coating or spray coating and used as a photoreceptor, or it can be used as a photoreceptor by drying, or from the above-mentioned organic solvent solution. Particles are produced using a mini-spray device, etc., and used as a dispersion liquid in which the particles are dispersed in an insulating liquid for photoelectrophoresis. Examples of conductive supports include paper; aluminum paper laminate; 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, paper, cellulose acetate, polyethylene terephthalate, etc., on which a metal such as chromium, silver, nickel, aluminum, or indium oxide is vapor-deposited, is 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 0.001 to 30 parts by weight, preferably 0.001 to 10 parts by weight, per 100 parts by weight of the photoconductive substance. In particular, as a mode of use of the composition of the present invention, a sensitizer can be incorporated into particles used in photoelectrophoresis to obtain images by photoelectrophoresis. Particles used in the photoelectrophoresis method are produced from a solution consisting of a photoconductive substance such as poly-N-vinylcarbazole and the sensitizer of the present invention using a mini-spray apparatus. These particles further contain insulating liquids containing saturated hydrocarbons such as decane, dodecane, octane, paraffin, and isooctane, preferably long-chain alkyls such as Isopar E, Isopar H, and Isopar G (manufactured by Etsuo Kagaku Co., Ltd., trade name). It is dispersed in a hydrocarbon to form a dispersion, which is used for photoelectrophoresis. Isopar E, Isopar H and Isopar G contain saturated hydrocarbons of 99.9, 99.3 and 99.3 respectively.
99.8% by weight, 0.05% aromatic hydrocarbons,
Contains 0.2 and 0.2% by weight. However, isopar H
Contains 0.5% by weight or less of olefin. The respective boiling points are 115°C to 142°C, 174°C to 189°C and 158°C to 177°C. The amount of particles in the dispersion is 0.5-10% by weight, preferably 1-3% by weight of the dispersion.
Weight%. The photoelectrophoresis method and its apparatus are described in Japanese Patent Publication No. 1983-20640. Necessary additives may be appropriately added to the photoconductive layer and particles to improve the properties of the photoconductive layer and particles. For example, an electrically insulating binder component can also be present in the photoconductive compositions of the present invention. Preferred binders for use in making the photoconductive compositions of the present invention are film-forming, hydrophobic polymeric binders with substantial dielectric strength and good electrical insulation. Representative examples of such substances include: natural resins such as vinyl resins, gelatin, cellulose ester derivatives, and cellulose nitrate; polycondensates including polyesters and polycarbonates; silicone resins; styrene-alkyd resins alkyd resins, including paraffin; and various mineral waxes; etc. Examples of specific polymeric materials useful as binders are described in Research Disclosure, Volume 109, pages 61-67 under the heading "Electrophotographic Elements, Materials and Methods." Generally, the amount of binder present in the photoconductive compositions of the present invention can vary. Typically, useful amounts of binder are from about 10 to about 100%, based on the total amount of the photoconductive material and binder mixture.
Within the range of 90% by weight. When producing photoconductive particles, a charge control agent,
Dispersion stabilizers may also be added. In particular, a copolymer of lauryl methacrylate and styrene (copolymerization ratio 4-2:
1) or a copolymer of 2-ethylhexyl methacrylate and styrene (copolymerization ratio 4:2-1
(weight ratio)) etc. are advantageously used. In addition, in order to improve flexibility and strength, plasticizers such as chlorinated diphenyl, dimethyl phthalate, and epoxy resin (trade name Epicoat) are added to 100 parts by weight of the photoconductive material.
It is also possible to add up to 60 parts by weight, preferably from 10 to 40 parts by weight. The coating thickness of the photoconductive composition of this invention on a suitable support can vary widely. Usually about 10
Forming a substantially colorless and transparent photoconductive composition layer that can be coated within a range of from microns to approximately 300 microns (before drying), has an optical density of approximately 0.05 or less for visible light; Can be done. It has been found that a preferred range of coating thickness before drying is within the range of about 50 microns to about 150 microns. However, useful results can be obtained even outside this range. The dry thickness of this coating may range from about 2 microns to about 50 microns. However, even if the thickness of the dried coating is between about 1 and about 200 microns, the photoconductive composition layer is colorless and transparent to visible light and is sensitive only to the far-infrared to near-infrared region. Obtainable. Production example of compound () which is a raw material compound (1) 2,6-di-t-butyl-4H-pyran-4
-Production of thione [compound ()]. 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 (). The ether extract and the oil not extracted with exane were combined and purified through a silica gel column using benzene, yielding an additional 6.8 g of crystals. (2) Production of 2,6-di-t-butyl-4H-thiopyran-4-thione [compound ()]. Dissolve 6.64 g of compound () in 330 ml of HMPA (hexamethylphosphoric triamide) and add 20
Argon gas was passed through for a minute. Heat and stir on an oil bath at 85 to 90°C, and under an argon atmosphere 19.8 g of water-fluidized sodium (Wako _Pure Chemical's NaSH.
) 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. The resulting crystals were filtered and dried. Recrystallization from hexane gave compound (). Yield 1.78g Yield 2.5% (3) 2,6-di-t-butyl-4-(methylthio)
Method for producing thiopyrylium iodide [compound ()]. 1.55 g of compound () 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 the compound (). Yield: 63% (4) Method for producing 2,6-di-t-butyl-4H-thiopyran-4-one [Compound ()]. 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. The reaction solution 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 mixed with benzene-diethyl ether in a ratio of 1:1 (volume ratio).
When passed through an alumina column using a mixed solvent of
740 ml of crystals of compound () 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-di-t under argon atmosphere
550 mg of -butyl-4H-thiopyran-4-one (compound) was dissolved in 20 ml of diethyl ether, and while cooling to about -10°C, 8.6 ml of a diethyl ether solution (2.7 mmole) of methylmagnesium iodide was added dropwise. . 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. filter the crystals,
Washed with cold water, further washed with diethyl ether and dried. The yield was 470 ml (yield 63%). Next, it was recrystallized from ethanol to obtain a colorless and transparent 2,6-di-t-butyl-4-methylthiopyrylium perchlorate (compound) with a melting point of 192-193°C.
was gotten. Below, a production example of the thiopyrylium salt used in the present invention will be shown as a reference example. Reference 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 electronic spectrum (nm), in cut: logε ε is extinction coefficient (in acetonitrile) 803 (5.34), 742 (4.89), 442 (3.82), 364 (4.35)
),
310 (3.98) Reference example 2 2,6-di-t-butyl-4-[3-phenyl-5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3 -dienyl]
- Synthesis method of thiopyrylium perchlorate [compound (4)] according to [manufacturing 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 ₃₉ 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 (wave number cm ^{- 1} ) 1480, 1160, 740 electronic spectrum (nm), in cutlet: logε ε is extinction coefficient (in acetonitrile) 806 (5.32), 744 (4.88), 444 (3.79), 364 (4.39)
),
310 (3.97) Reference example 3 2,6-di-t-butyl-4-[3-methyl-
5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]thiopyrylium perchlorate [(5) of compound (2)]
Synthesis method using [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 an oil bath at 110°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 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 (wave number cm ^{- 1} ) Synthesis method using 1482, 1180, 1135, 738 [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 cut: logε ε is extinction coefficient (in acetonitrile) 809 (5.33), 744 (4.90), 446 (3.77), 360 (4.30)
),
311 (4.01) Reference example 4 2,6-di-t-butyl-4-[3-bromo-
Synthesis method of 5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]thiopyrylium perchlorate [compound (7)] according to [Production 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 on an oil bath at 110°C for 15 minutes. After cooling, 50 ml of diethyl ether was added, and the precipitated crystals were filtered. Recrystallization from ethanol gave 5 mg of crystals with a melting point of 224-225°C. Yield 3
% Elemental analysis C ₃₁ H ₄₄ S ₂ ClBrO ₄ Calculated value C = 56.40% H = 6.72% S = 9.71% Actual value C = 56.51% H = 6.68% S = 9.55% Infrared absorption spectrum (wavenumber cm ^-1 ) 1485 , 1140, 740 Electron spectrum (nm), in cut: logε ε is extinction coefficient (in acetonitrile) 804 (5.35), 746 (4.92), 438 (3.88), 356 (4.22)
),
308 (3.98) Reference example 5 2,6-di-t-butyl-4-[3-chloro-
A method for synthesizing 5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]thiopyrylium perchlorate [compound (6)] according to [Production 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 further added and heated on an oil bath at 110°C for 10 minutes. 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 Electronic spectrum (nm), in Katsuko: logε ε is extinction coefficient (in acetonitrile) 806 (5.29), 746 (4.84), 438 (3.86), 360 (4.19)
),
310 (3.96) Reference example 6 2,6-di-t-butyl-4-[3-ethyl-
A method for synthesizing 5-(2,6-di-t-butyl-4H-thiopyran-4-ylidene)penta-1,3-dienyl]thiopyrylium perchlorate [compound (3)] according to [Production 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 on an oil bath at 115°C for 10 minutes. 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 Cl ₂ O 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), inside: logε ε is extinction coefficient (in acetonitrile) 807 (5.30), 748 (4.87), 446 (3.78), 360 (4.28
),
309 (3.99) [Example] 1 g of poly-N-vinylcarbazole and 1.5 mg of compounds (1) to (7) shown in the table below were dissolved in 10 g of 1,2-dichloroethane, and a rod bar was placed on an aluminum-deposited polyethylene terephthalate film. It was used and applied. Seven photoreceptors with photoconductive layers were prepared by drying at 55° C. for one day. The thickness of the photoconductive layer is approximately 2 μm. Since all of these photoconductive layers are transparent to visible light, a photoreceptor in which this photoconductive layer is provided on an aluminum vapor-deposited layer looks like the aluminum vapor-deposited layer itself, even though the photoconductive layer is provided thereon. It has the appearance of For this photoconductor, +6KV was obtained using a commercially available device.
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. As a result, the half-reduction exposure amount (E1/2) was as shown in the following table.

[Table] As described above, the photoconductive composition of the present invention is transparent to visible light and exhibits good photoconductive properties, and is suitable as a transparent photoconductive composition. Example 2 A high-quality paper made conductive by applying a 5% aqueous solution of polyvinyl alcohol and polyvinylbenzyltrimethylammonium chloride (weight ratio 1:1) to each side at a dry weight of 3 g/m ² on both surfaces of the high-quality paper. An electrophotographic paper having a transparent photoconductive layer was prepared by coating one side of the paper with a dispersion of a photoconductive composition having the following composition to a dry thickness of about 8 μm. Zinc oxide (SAZEX 2000 manufactured by Sakai Chemical) 100g Styrene-butadiene copolymer (PLIOLITE S-5D manufactured by Gutdeyer) 16g (as a solvent) Toluene 64g 2,6-di-t-butyl-4-[5-(2,6 −
di-t-butyl-4H-thiopyran-4-ylidene)pent-1,3-dienyl]thiopyrylium perchlorate (compound ()) 10 mg (as a solvent) dichloromethane 10 g After being charged to -400V by electric discharge, it was exposed to light using a spectrophotometer and developed using a magnetic brush method, and a spectral sensitivity peak was observed at a wavelength of 830 nm in the near-infrared region.

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)
A photoconductive composition comprising a penta-1,3-dienyl]thiopyrylium salt and a photoconductive substance. (Z represents an anion, and X represents a hydrogen atom, halogen, alkyl group, or aryl group.)