WO2012110402A1 - Trisazo compounds, processes for preparing them and use thereof - Google Patents

Abstract

The invention relates to new trisazo compounds which can be used as pigments, for example as photoconductors in the charge-generating layer of an electrophotographic device, to processes for preparing them and to the use thereof in an electrophotographic device. When used as photosensitive substances in a charge carrier generation layer, the new trisazo compounds lead to a massively increased photosensitivity at 400 to 480 nm.

Description

 Trisazo compounds, process for their preparation and their use

The invention relates to novel trisazo compounds which are used as pigments e.g. can be used as Fotoieiter in the charge-generating layer of an electrophotographic device, processes for their preparation and their use in an electrophotographic device.

Such electrophotographic apparatuses have been known for some time and in the simplest case consist of a layer containing an organic photogenerating compound and one provided with a conductive layer

Base material.

 However, the organic photoconductors used in such electrophotographic devices must meet a variety of partially exclusive criteria of photosensitivity, conductivity, and mechanical strength.

 The division of the photoconductive layer into a charge generating layer and an overlying charge transport layer enabled the use of new ones

Photosensitive materials regardless of the optimization of the

Charge transport properties and mechanical parameters.

As photosensitive substances, azo pigments are used in the charge-generating layer in addition to phthalocyanines, squarines, perylenes and a number of other substances. A wide range of diamines and naphtholic couplers have been used to prepare electrophotography

Bisazo pigments used. Later, trisazo pigments, e.g. tris (4-aminopheny!) amine as an amine component (Law, K.-Y. et al., US-A 5,422,211 1995). The synthesis of trisazo dyes by coupling the

Diazonium salt of the corresponding aromatic Triaminoverbundung with a variety of possible naphtholic couplers allows a broad optimization of the electrophotographic properties of the compounds by a suitable choice of triamines and couplers.

Trisazo dyes, the backbone of the 5H-tribenzo (a, f, k) trinden-5,10, 5-trione, are described in the patent DE 196 54 492 A1. Starting from the trinitro compound of the 5H-tribenzo (a, f, k), 5,10,15-trione, which has been reported by R. Seka et al. Already synthesized in 943, the corresponding tris-amino compound and the diazonium salt were prepared and trisazo compounds which absorb in the wavelength range above 500 nm with magenta couplers customary in the field of azochrome and for use as Charge generation Mater ^'tal suitable with green or red lasers for analog copiers with white light source or digital copiers and printers.

Modern digital printers or copiers use as their light source laser diodes which radiate in the near IR range. The charge-generating materials used in the OPC drums of these devices are predominantly phthalocyanine pigments and occasionally trisazo pigments. The bi-quality of the methods,

Characterized by the achievable resolution, was previously in

Essentially determined by the toner grain. At the present time, however, there are already toners of such small grain size that more and more the wavelength of the laser used becomes the limiting factor. Blue lasers would be e.g. able to ensure a higher resolution.

 So far, these have been too costly. But with the increasing popularity of the Blue ray DVD technology, a mass market for such has emerged

Laser diodes, so that their use in laser printers from a cost point of view is justifiable. Thus, charge generation materials with a pronounced absorption in the range of 400 to 450 nm are required.

Phthalocyanine pigments and azo compounds with magenta and cyan couplers are already described as charge generation materials for this range (US 2003049551A, Xerox) but have neither sufficient absorption in the short wavelength blue nor are they sufficiently active electrophotographically.

However, the use of commercially available azo-geibkuppiern revealed only a small hypsochromic shift.

The invention therefore an object of the invention to find new compounds that are used as dyes or charge-generating material in electrophotographic

Devices can be used in the short-wave (blue) range. Surprisingly, the coupling of truxenequinone diazonium salts with known yellow couplers used in the preparation of photographic films has resulted in corresponding compounds which are useful as pigments. The present invention relates to novel trisazo compounds of general formula 1:

Formula 1 wherein mean

R _4l R5 and RB are identical or different hydrogen, _{lower alkyl, lower alkoxy} or halogen and

 R-i, R2 and R3 are identical or different radicals (couplers) of the general formula 2

Formula 2 where

R _{A represents} a phenyl radical which is mono- or polysubstituted by lower alkyl

Lower alkoxy, phenoxy, phenylcarbonyl and / or halogen may be substituted, and

R is a lower alkyl radical, preferably methyl, ethyl or propyl, or an optionally mono- or polysubstituted by lower alkyl, lower alkoxy or halogen

represents substituted phenyl radical.

Preferably, R 1 to R 3 are the same or different per se

Coupling compounds of general formulas 2a and 2b:

Wherein the aryl group (R _a ) may be mono- or polysubstituted with R and the substituents for R - may be as defined under R _a -.

Particular preference is given to using compounds in which the radicals R 1 to R 3 are identical. Preferred radicals R _a are phenyl, optionally mono- or polysubstituted with substituents R, which are selected from Cl, F, methoxy, phenoxy and / or phenylcarbonyl.

Preferred radicals R are phenyl or methyl.

The radicals R ₄ , R ₅ and R ₆ are preferably hydrogen.

By lower alkyl are meant alkyl radicals having 1-8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, pentyl, etc.

By lower alkoxy are meant alkoxy radicals having 1-8 carbon atoms, such as, methoxy, ethoxy, propoxy, butoxy, etc.

Halogen is a fluoro, chloro, bromo or iodo substituent.

The novel tnsazo compounds can be prepared by coupling a diazonium salt of an aromatic triamino compound of general formula 3

Formula 3 wherein R ₄ to R _{s is defined} as mentioned under formula 1, are prepared with the couplers of formula 2. The coupling is carried out under such well-known conditions for the coupling, for example by at room temperature in

 Dimethyl sulfoxide, the components of the formulas 2 and 3 together and after addition of sodium acetate trihydrate, the mixture 4-5 hours under

Exclusion of light stirs.

The trisdiazonium salts of formula 3 are prepared by diazotization of the corresponding triamines also under conditions known per se, e.g. by adding sodium nitrite to the hydrochloric acid solution of the respective

Triamino compound at below 5 ° C and addition of an aqueous alkali or

Ammoniumtetrafluoroboratlösung. The triamino compounds are prepared in a known manner from the trinitro compounds by reduction, e.g. under

Use of activated Raney nickel in dimethylformamide at 100 ° C to 120 ° C and addition of hydrazine hydrate (98%). The trinitro compounds are obtained by nitration (Seka, R. et al., Monatsheft 74 (1943), p. 212) of trichloroquinones prepared by trimerization of indane-1, 3-dione (Ionescu, Chem. Ber

(1927), p. 1232).

The coupler compounds of general formula 2 are commercially available, e.g. by Acros Organics, Belgium.

The preparation of the new compounds is simple, so that very effective and durable systems can be obtained, which, as low cost, too

economically very interesting.

According to the invention, the abovementioned new trisazo dyes are used as pigments individually or as a mixture of at least two components in different mixing ratios, each component being able to be up to 90% in the charge generation layer

introduced electrophotographic device. The layer composite of this

The electrophotographic device comprises at least one surface provided with a conductive surface, an overlying charge generator layer containing the abovementioned trisazo compounds, optionally applied as a dispersion, and an overlying charge transport layer comprising at least one applied conventional charge transport compound, such as N, N ^" -Bis (3 methylphenyl -N, N ^{'bis-containing} ipheny ^ benzidine. The new trisazo compounds lead when used as photosensitive

Substances in a carrier generation layer of an electrophotographic device surprisingly result in drastically increased photosensitivity at 400 to 480 nm, preferably at 400 to 450 nm, in the emission of blue

Laser diodes. With this they can e.g. find use in laser printers.

The invention will be explained in more detail by examples: embodiment

Preparation of trisazo dyes of the general formula 1 in which R 1 to R ₃ = K in accordance with Table 1 and R ₅ to R ₅ = H are:

Beispiel 1

example 1

 Preparation of 2,7,2-triamino-5H-tribenzo (a, f, k) trinde-5,10,15-trione a) Trimerization of indane-1,3-dione 3,5g indane-1,3-dione Stir in concentrated sulfuric acid at room temperature for 15 min, allow to stand for 3 h, then pour into 500 g of ice-water, suction and wash until pH = 7 with water. Suspend the 5H-tribenzo (a, f, k) t-5, 0, 5-trione in water, boil and siphon off hot, then boil in glacial acetic acid and suction hot, stir in chloroform, suction, wash with acezone and Recrystallize from nitrobenzene. b) Nitration of 5H-tribenzo (a, f, k) triene-5,10,15-trione

0.01 mole (3.84 g) of 5H-tribenzo (a, f, k) trinde-5, 0.15-trione are dissolved in 150 ml

concentrated sulfuric acid at -10 ° C -5 ° C and stirred until everything is solved. Then added dropwise 0.036 mol of 100% nitric acid and stirred for one hour at this temperature and then 12 h at room temperature. Thereafter, the 2,7,12-trinitro-5H-tribenzo (a, f, k) trindene-5 ₎ 10,15-trione is poured onto 1000 g of ice, filtered off with suction, washed several times with water and finally with acetone. After drying, crystallized from nitrobenzene. c) Reduction of 2,7,12-trinitro-5H-tribenzo (a, f, k) trindee-5,10 _l 15-trione

A mixture of 0.01 mol (5.19 g) of 2,7,12-trinitro-5H-thbenzo (a ₎ f, k) trindee-5,10,15-trione and activated Raney nickel is dissolved in 1000 ml of DMF at 100 - 120 ° C suspended. Then added dropwise with stirring and Stickstoffeinieitung at this temperature, 25 ml of hydrazine hydrate (98%) slowly. The mixture is then stirred for one hour at 130-140 ° C., then filtered off with suction, the filtrate is concentrated to 40 ml and the 2,7,12-triamino-5H-tribenzo (a, f, k) is trindene-5,10,15- precipitated with ether.

Example 2

 Preparation of the 2,7,2-tris-diazonium-5H-tennobenzo (a, f, k) trindee-5,15-tri- intratra- trifluoroborate diazotization

0.01 Mo! (4.29 g) 2 ₎ 7,12-triamino-5H-thbenzo (a, f, k) thnden-5,10,15-trione is suspended in a mixture of 70 ml of water and 70 ml of concentrated hydrochloric acid and allowed to stand at a Temperature below 5 ° C a solution of 0.075 mole (5.17 g)

Sodium nitrite in 30ml of water slowly dropwise, the temperature does not exceed

5 ° C may rise. Subsequently, the reaction mixture is stirred at this temperature for 30 min and then added dropwise a solution of 0.045 mol (4.71 g) of ammonium tetrafluoroborate in 30 ml of water. The mixture is then stirred for 30 minutes at this temperature, sucks the 2,7,12-thsdiazonium-5H-tribenzo (a, f, k) trinden-5,10,15-trione tristetrafluoroborat, washed with a mixture of ethanol / ether ( 1: 1) and it dries.

Example 3

Preparation of the Target Compound 1 by Coupling Reaction with Compounds K 0.003 mol (2.19 g) of the 2,7,12-trisdiazonium-5H-tribenzo (a, f, k) trindee-5,10,15-tri- intratrafluoroborate are dissolved in 180 ml DMSO dissolved at room temperature. A solution of 0.0091 mol (2.7 g) of coupler K in accordance with the following Table 1 and 80 ml of DMSO is added dropwise rapidly and then 0.08 mol (2.448 g) of sodium acetate are added dropwise. added trihydrate. The mixture is stirred at room temperature with Lichtausschiuss five hours. Thereafter, the trisazo dye (according to Table 1) is precipitated with 11 water, filtered off, washed three times with boiling water and twice with Methanoi and dried.

To purify the dye, it is heated five times with 100 ml of methanol for 30 min and filtered off with suction. The mixture is then stirred five times with 100 ml of a mixture of DMF and methanol (1: 1) for 30 min and filtered off with suction while hot. Finally, the product is washed again with acetone and dried. Subsequent trisazo pigments were synthesized according to Example 3, wherein the couplers K were commercially available (acros) and were used according to the invention:

Table 1

Product No .: Structure of coupler (K) Name of trisazo dye

 1 2,7,12-tris (2-hydroxy-2-phenyl-1-phenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) triene-5,10, 5-trione

2,7,12-tris- (2-hydroxy-2-phenyl-1- (2-chloro-phenylcarbarnoyl-vinylazo)) - 5H-tribenzo (a, f, k) -trinde-5, 10, 15- trione

2,7,12-Tris-{2- ydroxy-2-phenyl-1-(2- methoxy-phenylcarbamoyl-vinylazo))-5H- Tribenzo-(a,f,k)trinden-5, 10, 15-trion 3 2,7,12-tris- (2-hydroxy-2-phenyl-1 - (2,4-dichloro-phenylcarbamoyl-vinylazo)) - 5H-thbenzo- (a, f, k) -trinde-5, 10, 15-trione

2,7,12-Tris {2-ydroxy-2-phenyl-1- (2-methoxyphenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) triene-5, 10, 15-trione

 HN

CH ₃ 0 ^^>

2,7,12-tris- (2-hydroxy-2-phenyl-1- (2-fluoro-phenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) -trinde-5, 10, 15-trione

2,7,12-tris- (2-hydroxy-2-phenyl-1 - (4-phenoxyphenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) triene-5, 10, 5 trione

 2,7-tris (2-hydroxy-2-phenyl-1- (2-hydroxy)

HO v benzoyl-phenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f _t k) -trene-5, 0, 15-trione

HN

2,7,12-tris - (2-hydroxy-2-phenyl-1- (2-benzoyl-4-chloro-phenylcarbamoyl-vinyl-azo)) - 5H-tribenzo (a, f, k) triene-5,10 , 15-trione

Example 4

 Proof of the electrophotographic properties The electrophotographic properties of the tabular images

 Trisazo dyes 1 to 8 were determined in a bilayer system. For this purpose, an aluminized polyester substrate was coated with a dispersion which contains the respective trisazo compound as pigments in a polyvinyl butyral solution in methylene chloride. The obtained in this way after drying

Carrier generation layers were coated (with a solution of N, N ^"-bis- 3- methylphenylJ-NN ^'-bis-ipheny ^ benzidine in polycarbonate Z200 in methylene chloride and measured after drying.

The results are shown in Table 2. All connections emit in the blue range.

Table 2

In this mean:

You = dark waste

 Uo = Aufladepotentiai

E0,5 = 1 / amount of light necessary to reduce Uo to 50% Ur = residual potential at 6 μϋ / cm ² for white light

 λ = measuring wavelength

Claims

claims 1. Trisazo compounds of the general formula 1

Formula 1 wherein mean R, R5 and R _{6 are} identical or different and are hydrogen, lower alkyl (Ci to CB), lower alkoxy (Ci to C _a ) and / or halogen and Ri, R ₂ and R _{3 are the} same or different compounds of general formula 2

Formula 2 where R _{a represents} a phenyl radical which is mono- or polysubstituted by lower alkyl (C 1 to C _B ), lower alkoxy (C 1 to C _e ), phenoxy, phenylcarbonyl and / or Halogen may be substituted, and R _{b is} a lower alkyl radical (Ci to C _a ) or an optionally mono- or polysubstituted by lower alkyl (Ci to C _a ), lower alkoxy (Ci to C ₈ ) and / or Represents halogen-substituted phenyl radical. 2. trisazo compound according to claim 1, characterized in that the radicals Rt to R _{3 are} identical or different coupler compounds of the general formulas 2a and 2b

Formula 2a Formula 2b where R _a Pheny! is, which may be mono- or polysubstituted with R, wherein the substituents for R represent the substituents defined under R _a and R _{b is} phenyl or methyl. 3. trisazo compound according to claim 1 or 2, characterized in that the radicals Ri to R3 are the same. 4. trisazo compound according to any one of claims 1 to 3, characterized in that the radicals R ₄ to Re are hydrogen. 5. trisazo compound according to any one of claims 1 to 4, characterized in that R _{a is} phenyl, optionally mono- or polysubstituted with substituents selected from the group Cl, F, methoxy, phenoxy and / or phenylcarbonyl. 6. trisazo compound according to one of claims 1 to 5 selected from  2,7,12-tris- (2-hydroxy-2-phenyl-1-phenylcarbamoyl-viny! Azo)) - 5H-tribenzo (a, f, k) triene-5,10,15-trione;  2,7,12-Tris (2-hydroxy-2-phenyl-1- (2-chloro-oro-phenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) triene-5, 10, 15 -trione;  2,7,12-Tris (2-hydroxy-2-phenyl-1- (2,4-dichloro-phenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) triene-5, 10, 15 -trione; 2,7 ₎ 12-Tris (2-hydroxy-2-phenyl-1- (2-methoxyphenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) -trione-5,15-trione ; 2,7,12-tris- (2-hydroxy-2-phenyl-1 - (2-fluoro-phenylcarbamoyl-vinyiazo)) - 5H-tribenzo-fa.f.k.-jindlene-S, 10, 15-trione;  2,7, 12-Tris {2-hydroxy-2-phenyl-1- (4-phenoxy-phenyl [carbamoyl-vinylazo)] - 5H-tribenzo (a, f, k) triene-5,10,15 -trione;  2,7,12-Tris (2-hydroxy-2-phenyl-1- (2-benzoyl-phenylcarbamoyl-vinylazo)) - 5H-tribenzo (a, f, k) triene-5, 10, 15-trione ;  2,7,12-Tris- (2-hydroxy-2-phenyl-1- (2-benzoyi-4-chloro-phenylcarbamoyl-vinyl-azo)) - 5H-tribenzo (a, f, k) triene-5, 0 , 5-trion. 7. A process for preparing trisazo compounds of general formula 1, according to any one of claims 1 to 6, characterized in that a diazonium salt of the corresponding aromatic triamino compound of the general formula! 3

Formula 3 wherein R ₄ to R _{6 have} the meaning mentioned under formula 1, at room temperature in dimethyl sulfoxide with a compound of the general Formula 2 mixed and with the addition of sodium acetate trihydrate, the mixture is stirred for 4-5 hours under Ausausschiuss until the  Target connection has arisen. 8. Electrophotographic device consisting of one with a conductive  Surface provided underlay, at least one overlying  A charge generation layer and a charge transport layer above, characterized in that the charge generation layer  Trisazo compounds according to any one of claims 1-6, individually or in admixture.