JPS6154056B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel thiopyrylium dye and a method for producing the same. 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 of Davis et al., vanAllan.
as a spectral sensitizer for photoconductors, particularly as a spectral sensitizer for organic photoconductors, as described in US Pat. No. 3,250,615 to Reynolds et al., US Pat. Useful. Photoconductors sensitized with thiopyrylium and pyrylium dyes are used in a variety of applications, such as those disclosed in the above-mentioned patent specifications, but they are particularly important for xerography and electrofax electrophotography. be. However, such conventionally known thiopyrylium dyes have a drawback of having multiple absorption bands in the visible region. In particular, almost all dyes also exhibit absorption in the blue region. That is, this sensitizing dye spectrally sensitizes in multiple wavelength ranges. Therefore, when this thiopyrylium dye is used as a sensitizer for photoconductive particles to carry out color copying, for example, when obtaining color images with trichromatic mixed particles by photoelectrophoretic electrophotography, it poses a serious problem. Collide. Photoelectrophoresis electrophotography, as detailed in U.S. Pat. No. 3,384,448, is a process in which a suspension of photoconductive photosensitive particles is suspended in an insulating liquid, at least one of which is transparent to light. When placed between two electrodes and exposed to light through the transparent electrode by applying a differential voltage, the photoconductive photosensitive particles that have received this image exposure selectively move to one of the electrodes, producing a visible image. It is a photographic method. When this electrophotographic method is used for color copying, cyan particles that are sensitive to red light, magenta particles that are sensitive to green light, and yellow particles that are sensitive to blue light are used as photosensitive particles, and a mixture of these three color particles is used. When the suspension is exposed to white light through a multicolor original image, for example, a color slide, in the above-mentioned apparatus, a color positive or color negative image can be obtained on the transparent electrode by a subtractive color method with one exposure. As disclosed in U.S. Patent No. 3,384,448, Japanese Patent Publication No. 43-21781, Japanese Patent Application Laid-open No. 52-143827, and elsewhere, the main absorption band of these particles mainly coincides with the main photosensitivity response. In addition to the three-color photoconductive pigments of cyan, magenta, and yellow, as described in U.S. Pat. No. 3,384,448, the photoconductor contains a spectral sensitizer to make it sensitive to visible light. Photosensitive particles can also be used. When a color image is obtained using three-color mixed particles by such photoelectrophoretic electrophotography, if a known thiopyrylium dye is used as a spectral sensitizer for the photosensitive particles, spectral sensitization occurs in multiple wavelength ranges as described above. Therefore, only images with poor color separation could be obtained. In other words, known thiopyrylium dyes were unsuitable for color photography using photoelectrophoretic electrophotography. In order to solve the above-mentioned drawbacks, the inventor of the present invention has made repeated studies and found that it does not have the above-mentioned drawbacks and is more effective for photoconductors than conventional thiopyrylium dyes.
We have discovered a new thiopyrylium dye that provides high sensitizing ability and a method for producing the same, and have completed the present invention. An object of the present invention is to provide a thiopyrylium dye that provides high sensitizing ability to photoconductive substances and a method for producing the dye. Furthermore, the purpose of the present invention is to
An object of the present invention is to provide a thiopyrylium dye for obtaining images with excellent color separation and a method for producing the dye. The thiopyrylium dye of the present invention is a 2,6-di-t-butyl-4-[4-(diethylamino)phenyl]thiopyrylium salt represented by the following chemical structural formula (). The anion represented by Z includes known single atomic ions or atomic group ions consisting of a plurality of atoms having a negative charge, and is preferably a strong acid anion represented by HZ with a pKa of 5 or less, preferably a pKa of 2 or less. . Specific examples of anions include monatomic ions such as halogen anions, such as fluoride, chloride, bromide, and iodide. The atomic group ions include organic anions such as trifluoroacetate, trichloroacetate, p-toluenesulfonate, and perchlorate, periodate, tetrachloroaluminate, trichloroferrate (), tetrafluoroborate, hexafluorophosphate, Inorganic anions include sulfate, hydrogen sulfate, and nitrate. Among these, in the case of divalent anions, formally 1/2 of the anion
is interpreted to represent a monovalent anion. Among these anions, chloride, bromide, perchlorate, tetrafluoroborate, p-toluenesulfonate, and trifluoroacetate are preferred. Such thiopyrylium dyes are composed of 2,6-di-t-butyl-4H-thiopyran-4-one [compound ()] represented by the chemical structural formula () below and an organic metal represented by the general formula () below. It is obtained by reacting the compound [compound ()] and then treating with an acid. (Manufacturing method) In the formula, M represents a monovalent, divalent or trivalent metal; a monohalogenated divalent metal; or a dihalogenated trivalent metal, such as MgBr, MgI,
Preferred are MgCl, CaI, Li, Na, K, Be, and Al, and most preferred are MgBr and Li. Specific examples of compounds represented by the general formula () are 4-
diethylaminophenylmagnesium bromide,
4-diethylaminophenylmagnesium chloride, 4-diethylaminophenyl lithium, 4-
Diethylaminophenyl sodium, tri(4-
diethylaminophenyl) aluminum, di(4
-diethylaminophenyl) beryllium. The reaction is preferably carried out in a solvent, and a non-aqueous solvent substantially free of water can be used as the solvent. Examples of solvents include dimethyl ether, methyl ethyl ether, diethyl ether, dimethoxyethane, tetrahydrofuran,
Examples include ether compounds such as 1,4-dioxane, aromatic compounds such as benzene and toluene, and saturated hydrocarbon compounds such as pentane, hexane, cyclohexane, methylcyclohexane, and petroleum ether. Generally, the reaction temperature is preferably from -78°C to the heating reflux temperature of the reaction solvent used, and the reaction time is preferably from 10 minutes to 3 hours. However, the most preferred reaction temperature and reaction time largely depend on the type of organometallic compound and solvent used. For example, when diethyl ether is used as the solvent and 4-diethylaminophenylmagnesium bromide is used as the organometallic compound, the reaction time ranges from about -20°C to about +30°C, and the reaction time ranges from about 30 minutes to about 90 minutes.
It can be carried out within minutes. The amount of organometallic compound ranges from 1 mol to about 10 mol, preferably from 1 mol to about 3 mol, per mol of compound (). The reaction is preferably carried out under an oxygen-free atmosphere. An oxygen-free atmosphere means a rare gas such as helium or argon, or an inert gas such as nitrogen. These gases are used to replace air to form a substantially oxygen-free condition, and the reaction is allowed to proceed under this condition. The pressure of the rare gas or inert gas can be around 1 atm, but the pressure is not limited to this value and can be selected as appropriate. The compound obtained by reacting the compound () with an organometallic compound is 2,6-di-t-butyl-4-hydroxy-4-(4'-diethylaminophenyl)-
It is 4H-thiopyran and is represented by the structural formula (). In the process of producing the compound of the present invention, the dye of the present invention is produced in a high yield by immediately treating the compound () with an acid without isolating it, and precipitates it in the solvent. The method for producing the compound of the present invention is characterized by high yield and easy isolation of the target compound. To activate the organometallic compound, hexamethylphosphoric triamide, N.N.
N'・N'-tetramethylethylenediamine, 1.
4-Diazabicyclo[2.2.2]octane or the like may also be added. As acids that can be used to produce the compounds of the present invention, acids with a pKa of 5 or less, preferably acids with a pKa of 2 or less are useful, and specific examples of acids include hydrofluoric acid, hydrochloric acid, Hydrohydric acid, hydriodic acid, perchloric acid, periodic acid, tetrafluoroboric acid,
These are hexafluorophosphoric acid, sulfuric acid, nitric acid, trifluoroacetic acid, and p-toluenesulfonic acid. Z in the acid (HZ) becomes the anion of the compound (). The amount of acid used is sufficient to obtain compound () from compound (), and a large excess can be added. 2,6-di- which is one of the raw material compounds of the present invention
t-Butyl-4H-thiopyran-4-one [compound ()] is a new compound, 2,6-di-t-butyl-4-one represented by the chemical structural formula below.
(Methylthio)thiopyrylium salt or 2.
It is obtained by hydrolyzing 6-di-t-butyl-4H-thiopyran-4-thione. However, in the above hydrolysis reaction, 2.
2,6-di-t-butyl-4-(methylthio)thiopyrylium salt
It can be produced in higher yield than the method of hydrolyzing butyl-4H-thiopyran-4-thione, and is practical. This hydrolysis reaction is carried out in water or a water-miscible and highly polar solvent such as dimethyl sulfoxide, sulfolane, hexamethyl sulfolyl triamide. The above 2,6-di-t-butyl-4-(methylthio)thiopyrylium salt and 2,6
-di-tert-butyl-4H-thiopyran-4-thione is a new compound and is described in Reynolds et al., Journal of Heterocyclic Chemistry, Vol. 11.
It was synthesized through the following steps from 2,6-di-t-butyl-4H-pyran-4-one synthesized by the method described in Vol., p. 1075 (1974). That is, after heating 2,6-di-t-butyl-4H-pyran-4-one in the presence of phosphorus pentasulfide [step (1)], it is heated with an alkali sulfide such as sodium sulfide or water under an inert gas flow. React with an alkali hydrosulfide such as potassium sulfide [step (2)], and further react with a methylating agent [step (3)]. It is preferable that each step is carried out in batches rather than continuously. In the above chemical formula, ^-But represents -(C(CH3) _{3 )} . The compound () represented by the general formula (), which is another raw material compound for thiopyrylium dye, is generally obtained by the reaction of 4-diethylaminophenyl halide with a metal.For example, 4-diethylaminophenylmagnesium bromide is , Research Disclosure 15742 (p. 79) by the reaction of 4-diethylaminophenyl bromide with magnesium, and 4-diethylaminophenyl lithium was converted into 4-diethylaminophenyl bromide according to the method of May (1977). prepared by reaction with lithium.Other organometallic compounds ()
"Preparatire" by Weygand & Hilgetag
Organic Chemistry” John Wiley & Sons,
Inc., (1975) (pp. 748-809). Furthermore, the thiopyrylium dye of the present invention has 2.6
It can also be obtained by reacting -di-t-butyl-4H-thiopyran-4-one [compound (2)] with diethylaniline in the presence of phosphorus pentoxide and phosphorus oxychloride. In addition, as a method for obtaining the thiopyrylium dye of the present invention, 2,6-di-t-butyl-4-(methylthio)thiopyrylium salt and the organometallic compound represented by the general formula () used in the present invention described above can be used. It can also be produced by reacting with an acid after the reaction. However, production method (i) is most preferred in terms of yield and ease of handling. FIG. 1 shows the spectral sensitivity spectrum when the novel thiopyrylium dye according to the present invention is used as a spectral sensitizer for poly-N-vinylcarbazole.
FIG. 2 shows a spectral sensitivity spectrum when a conventional thiopyrylium dye is used. As is clear from a comparison of Figures 1 and 2, the new thiopyrylium dye has 2 and 6 thiopyran rings.
Because it has a t-butyl group in the t-butyl group, unlike conventional aryl group-containing dyes, there is no sub-absorption around 400 nm, and photoconductor compositions using this new thiopyrylium dye as a spectral sensitizer can be used in the visible range. It is not sensitive to light in the blue region, especially from 400 to 450 nm. Therefore, color photoelectrophoretic electrophotographic photosensitive particles containing this new thiopyrylium dye as a sensitizer are different from those made using known thiopyrylium dyes, and have improved color separation from blue-sensitive yellow particles. can do. Magenta particles containing compound () as a sensitizing dye in the green region also provide images with good color separation that do not mix with yellow particles. Furthermore, when the new thiopyrylium dye () is used as a sensitizer for photoconductors, especially organic photoconductors such as poly-N-vinylcarbazole, triarylamine, triarylmethane, etc. It has been found that this provides a highly sensitive photoconductor. The reason for this is not yet clear, but one of the reasons seems to be that the t-butyl substituent of compound () increases its compatibility with the organic photoconductor. Example 1 Preparation of 2,6-di-t-butyl-4-[4-(diethylamino)phenyl]thiopyrylium perchlorate [compound ()] (i) 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 or aqueous ammonia was added to the residue to decompose the phosphorus pentasulfide, and then extracted with ether. The benzene solution was dried using anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. After extraction with hexane and concentration, it becomes 16.0
A reddish crystal of g was obtained. 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. Total yield 22.8g, yield 61%, melting point 108-108.5
℃, 2.6- of flesh-colored crystals (hexaline recrystallization)
Di-t-butyl-4H-pyran-4-thione was obtained. 6.64 g of this compound was dissolved in 330 ml of hexamethylene phosphoric triamide and purged with argon gas for 20 minutes. Heat and stir on an oil bath at 85-90°C, and add 19.8 g of sodium bisulfide (Wako Pure Chemicals NaSH xH ₂ O about 70% to 70-80% of phosphorus pentoxide under an argon atmosphere).
) 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. Recrystallized from hexane. Red crystals of 2,6-di-t-butyl-4H-thiopyran-4-thione with a melting point of 162° C. were obtained in an amount of 1.78 g and a yield of 25%. Then this compound 1.55
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. The product was 2,6-di-t-butyl-4-(methylthio)thiopyrylium iodide with a yield of 63% and a melting point of 150°C to 155°C (decomposed). 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 passed through an alumina column using a 1:1 mixed solvent of benzene diethyl ether to obtain 740 mg of crystals. Yield 97%, recrystallized from cyclohexane.
Colorless crystals of 2,6-di-t-butyl-4H-thiopyran-4-one with a melting point of 97-98°C were obtained. Elemental analysis value Calculated value as C ₁₃ H ₂₀ SO C = 69.59%, H =
8.99%, S = 14.29%, measured value C = 69.13%, H
= 9.06%, S = 14.41% Mass spectrometry value (m/e) 224 (30%), 181 (100
%) Infrared absorption spectrum (wave number cm ^-1 ) 1610, 1348, 880, 730, nuclear magnetic resonance spectrum (chemical shift, unit ppm, trimethylsilane reference) (proton) 99.6MHz Area in singlet 1.38, 6.90 in deuterated chloroform, respectively The ratio is 9:1 (carbon-13) 183.00 in 25.5MHz deuterium chloroform;
165.38, 124.32, 38.38, 30.54 Visible/ultraviolet absorption spectra (wavelength nm, log ε in brackets, in cyclohexane 222 (3.85), 285 (4.17), 329 (1.57), 363
(0.96) (ii) 2,6-di-t-butyl-4H-thiopyran- prepared in this way under an argon atmosphere
A solution of 0.206 g of 4-one dissolved in 30 ml of diethyl ether was cooled to 0°C, and 4 ml of a tetrahydrofuran solution containing 2 mmole of 4-diethylaminophenylmagnesium bromide was added.
was instilled for 30 minutes. After the addition was completed, stirred at room temperature for 1 hour, poured the reaction solution into 100ml of 2% perchloric acid aqueous solution,
The resulting crystals were filtered, washed with water, and dried. Recrystallization from ethyl acetate gave compound (). Yield 0.327g, needle crystal melting point 217-218℃ Elemental analysis value Calculated value as C ₂₃ H ₃₄ NSClO ₄ C = 60.57%, H
=7.51%, N=3.07%, S=7.03%, Measured value C
=60.59%, H=7.58%, N=3.05%, S=7.12
% Infrared absorption spectrum (wave number cm ^-1 ) 1560, 1275, 1213, 1090 Nuclear magnetic resonance spectrum (chemical shift, unit ppm, in deuterated chloroform based on trimethylsilane) (S, d, t, and q in the cutout are singlets, respectively) , represents a doublet, triplet, or quartet, and the number before H represents the area ratio or J represents the coupling constant (in Hertz) 1.28 (t, 6H, J = 7.08), 1.60 (S ,
18H), 3.56 (q, 4H, J = 7.08), 6.93 (d,
2H, J=9.28) 8.06 (d, 2H, J=9.28),
8.34 (S, 2H) Ultraviolet/visible spectrum (wavelength nm, ε in cutlet, in acetonitrile)
532 (62, 200), 288 (11, 300), 259 (7,
700) Example 2 1 g of poly-N-vinylcarbazole and 3 mg of compound () were dissolved in 10 g of 1,2-dichloroethane, and the mixture was placed on a polyester film deposited with aluminum.
It was applied using a No. 16 rod bar. A photoreceptor was prepared by drying at 55°C for one day. This photoreceptor was charged to +450V by performing a +6kV corona discharge using a commercially available device, and then the surface was irradiated with light using a tungsten lamp at an illuminance of 4.5 lux to raise its surface potential.
The exposure amount was obtained by determining the time (seconds) it took for the voltage to reach 225V. The result was E1/2 = 47 lux seconds. Comparative Example 1 A photoreceptor was prepared according to the same photoreceptor manufacturing method as in Example 2, except that the compound () shown in Table 1 below was used instead of the compound () in Example 1, and these photoreceptors are described below. The same measurements as in Example 2 were carried out, and the results shown in Table 1 were obtained. This Comparative Example 1, using a known thiopyrylium dye (), is a control for comparison with Example 2.

[Table] The embodiments are shown below. (1) 2,6-di- expressed by chemical structural formula ()
t-Butyl-4-[4-(diethylamino)phenyl]thiopyrylium salt. (2) 2,6-di- expressed by the chemical structural formula ()
t-Butyl-4H-thiopyran-4-one and After reacting with an organometallic compound represented by the following general formula (), 2,6-di-t-butyl- represented by the chemical structural formula (), which is treated with an acid.
Method for producing 4-[4-(diethylamino)phenyl)thiopyrylium salt. In the above formula, Z represents an anion and M is 1
represents a valent, divalent or trivalent metal, a monohalogenated divalent metal; or a dihalogenated trivalent metal, and n is an integer of 1 to 3. (3) The thiopyrylium salt according to embodiment (1), wherein Z is an anion of a strong acid with a pKa of 5 or less. (4) Z is a halogen anion, an organic anion such as trifluoroacetate, trichloroacetate, p-toluenesulfonate, perchlorate, periodate tetrachloroaluminate, trichloropherate (), tetrafluoroborate, Hexafluorophosphate, sulfate, hydrogen sulfate,
Embodiment (1) where the anion is selected from the group consisting of inorganic anions such as nitrate.
thiopyrylium salt. (5) The acid is hydrofluoric acid, hydrochloric acid, hydrobromic acid,
The production method according to embodiment (2), which uses hydriodic acid, perchloric acid, periodic acid, tetrafluoroboric acid, hexafluorophosphoric acid, sulfuric acid, nitric acid, trifluoroacetic acid, and p-toluenesulfonic acid. (6) The method according to embodiment (2), wherein the reaction with the organometallic compound represented by the general formula () is carried out in a solvent between -78°C and the reflux temperature of the solvent. (7) The amount of the organometallic compound represented by the general formula () is 2,6-di-t-butyl-4H-thiopyran-4-one 1 represented by the chemical structural formula ().
The production method of embodiment (2) in which the ratio is 1 to 10 moles to moles.

[Brief explanation of the drawing]

Figure 1 shows the spectral sensitivity spectrum when the novel thiopyrylium dye of the present invention is used as a spectral sensitizer for poly-N-vinylcarbazole.
The figure shows a conventionally known thiopyrylium dye dyed with poly-N-
This is a spectral sensitivity spectrum when vinyl carbazole is used as a spectral sensitizer.

Claims (1)

[Claims] 1. 2,6-di- represented by the chemical structural formula ()
t-Butyl-4-[4-(diethylamino)phenyl]thiopyrylium salt. 2 2,6-di- represented by chemical structural formula ()
t-butyl-4H-thiopyran-4-one, After reacting with an organometallic compound represented by the following general formula (), Chemical structure characterized by treatment with acid ()
2,6-di-t-butyl-4-[4
-Production method of (diethylamino)phenyl]thiopyrylium salt. In the above formula, Z represents an anion and M is 1
represents a valent, divalent or trivalent metal; a monohalogenated divalent metal; or a dihalogenated trivalent metal, and n is an integer of 1 to 3.