WO1996000208A1

WO1996000208A1 - Oligomer liquid crystal triphenylene derivatives and their use as charge carrying substances in electrophotography

Info

Publication number: WO1996000208A1
Application number: PCT/EP1995/002484
Authority: WO
Inventors: Lukas HÄUSSLING; Karl Siemensmeyer; Karl-Heinz Etzbach; Helmut Ringsdorf; Peter Schumacher; Dietrich Haarer; Dieter Adam; Juergen Simmerer; Wolfgang Paulus
Original assignee: Basf Aktiengesellschaft
Priority date: 1994-06-27
Filing date: 1995-06-26
Publication date: 1996-01-04
Also published as: DE4422332A1; EP0767776A1; JPH10502065A

Abstract

Compounds have the general formula (I) Z[-Y?1-(A-Y2)¿m-X]n, in which the variables have the following meanings: Z stands for an n-valent aliphatic residue with 2 to 20 C atoms or for an n-valent three to seven-membered saturated or unsaturated carbocyclic or heterocyclic residue that may also be benzocyclised, or for an n-valent siloxane or cyclosiloxane residue with up to 10 Si atoms; Y1, Y2 stand for a chemical bond, oxygen, sulphur or a group -CO-O-, -O-CO-, -N(R)-CO- or -CO-N(R)-; m equals 0 or 1; A stands for an alkylene group with 2 to 20 C atoms in which non-adjacent C atoms may be substituted by oxygen, sulphur, -CO-O-, -O-CO- or -N(R)-; n equals 2 to 6; R stands for hydrogen or C¿1?-C4-alkyl; and X stands for a substituted triphenylene residue. Because they recur n times in the compounds, A, Y?1, Y2¿, m and X may be the same or different. These compounds are useful as charge carriers.

Description

Oligomeric liquid-crystalline triphenylene derivatives and their use as charge transport substances in electrophotography

5 Description

The present invention relates to compounds of general formula I.

Z [—Y ¹ - (A — γ2) _m _χ] _n i,

10 in which the variables have the following meaning:

Z is an n-valent aliphatic radical with 2 to 20 C atoms or an n-valent three- to seven-membered saturated or unsaturated carbocyclic or heterocyclic radical, which can also be benzo-fused or an n-valent siloxane or cyclosiloxane radical with up to 10 Si atoms

20 γi, γ2 a chemical bond, oxygen, sulfur or a group —CO — 0—, —0 — CO—, —N (R) —CO— or -NCR) -,

m 0 or 1,

25

A is an alkylene group with 2 to 20 carbon atoms, in which non-adjacent carbon atoms can be replaced by oxygen, sulfur, —CO — 0—, —0 — CO— or —N (R) -,

30 _n 2 to 6,

R is hydrogen or -CC ₄ alkyl and

X is a substituted triphenylene radical, 35 where A, Y ¹ , Y ² , m and X, because they occur n times in the compounds, can be the same or different and the use of these compounds as charge transport compounds in photocopiers and laser printers and in electrochemical cells, 40 electronic components and optical display devices.

Organic photoconductors have been known for a long time and are used primarily in xerography as electrophotographic recording materials (Schaffert, IBM J. Res. Develop., 45 1971, 75). Organic photoconductors are currently used in molecular dispersion in a neutral binder in photocopiers and laser printers (Borsenberger, J. Phys. Chem., 1993, 11314). Such arrangements have a typical maximum carrier mobility of 10 ^{~ 5} cm ² / Vs. Charge carrier mobility in this order of magnitude, however, limits the printing or copying speed of electrophotographic devices, so that a further increase in speed only appears possible by increasing the charge carrier mobility. However, this cannot be achieved with the conventional methods currently used.

In work by Closs et al. (Licjuid Crystals, 14 (3), 629 (1993), Bengs et al. (Liquid Crystals, 15 (5), 565 (1993) and Adam et al., Phys. Rev. Lett., 70 (4), 457 (1993) was able to show that hexapentyloxytriphenylene has photoconductive properties in the liquid-crystalline phase Since the operating temperatures of a photocopier are in a temperature range of 20 ° C to 50 ° C, the observed transport phenomena must also be in this range is not the case with hexapentyl oxytriphenylene.

Furthermore, a photoconductor layer must be able to withstand a certain mechanical load, such as occurs in individual process steps (concreting the charge image, transferring the toner image).

The object of the present invention was therefore to provide new liquid-crystalline materials which, in addition to photoconductive properties, have a liquid-crystalline phase in the temperature range between 20 ° C. and 50 ° C. and are mechanically loadable.

Accordingly, the triphenylene derivatives of the formula I identified above have been found.

The linking group Z is, especially for n = 2, preferably an alkylene radical with 2 to 20 C atoms, particularly preferably with 2 to 6 C atoms, for n = 3 preferably an alkylene radical or a three- to seven-membered saturated or unsaturated carbocyclic or heterocyclic radical or a cyclosiloxane radical and, especially for n = 4.5 or 6, preferably a cyclosiloxane radical or an optionally substituted tri-phenylene radical.

Preferred groups Z are furthermore the siloxane groups of the general formula for n = 2

in which r represents a number from 1 to 9, or

for n = 3 to 6 the cyclic siloxane groups of the formula

in which s is a number from 3 to 6.

Preferred groupings Z (—Y ¹ -) _n are those which are derived from the compounds Z (- ^ Y ¹ H) _n listed below:

1,3,5-cyclohexane tricarboxylic acid, 1,3,5-benzenetricarboxylic acid, maleic acid, fumaric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, ethylene glycol, propylene glycol, 1,3-dihydroxypropylene, 1,4- Dihydroxybutylene, 1, 5-dihydroxypentylene, 1,6-dihydroxyhexylene, 1, 8-dihydroxy octylene and 1, 10-dihydroxydecylene.

In particular when n ≥ 3, a preferred group Z is a triphenylene radical, particularly preferably an unsubstituted triphenylene radical.

The spacing-apart molecular part A is preferably an unbranched α, ω-alkylene group with 3 to 20 C atoms, particularly preferably with 4 to 12 C atoms. This applies in particular to the case where Z is a linear or cyclic siloxane radical. Preferred groupings —Y ¹ —A — Y ² - are for example

(CH ₂ ) _p 1 'O (CH ₂ ) _p <0— (CH ₂ ) _p 2 —CO 0 -

CO (CH ₂ ) 2 OO and 0 (CH ₂ ) 3 O,

where p ^{1 is} a number from 2 to 12, p ^{2 is} a number from 2 to 10 and p ^{3 is} a number from 2 to 11. If the central unit Z is also an al ylene group, m is preferably 0, ie the triphenylene radical X is linked directly to the central unit via Y ¹ .

The substituted triphenylene radicals X preferably have the following structure

where the radicals R ¹ to R ^{5 are} preferably fluorine, chlorine, bromine, iodine, nitro, cyano, C ₁ -C ₂ o -alkyl, C ₁ -C ₂ -alko y, C ₁ -C ₂ -alkylthio, C ₁ -C ₂ o-Alkanoyl, -C-C ₂ o-alkenyl, -C-C ₂ o-alkynyl mean, the carbon chains in these radicals also by non-adjacent oxygen or sulfur atoms or by —COO—, —OCO— or —N (R) - Groups can be interrupted.

The following radicals R ¹ to R ⁵ are in particular:

Alkyl radicals such as methyl, ethyl, propyl, butyl, pentyl, hexyl,

Heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl and hexadecyl. Of these, the alkyl radicals having 4 to 16 carbon atoms are preferred, particularly preferably the butyl, pentyl, hexyl, heptyl, octyl and nonyl radicals.

In all aliphatic radicals, carbon chains can be interrupted by non-adjacent oxygen or sulfur atoms or by —COO—, —OCO— or - (R) groups, in particular the latter by —NH— or - CH ₃ -.

Also suitable as substituents R ¹ to R ^{5 are} especially aliphatic groups which have double or triple bonds in their carbon chain, for example ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, dodecenyl, tetradecenyl, hexadecenyl , Ethynyl, propynyl,

Butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, dodecynyl, tetradecynyl or hexadecynyl, the double or triple conditions preferably being terminal. Aliphatic groups with double and triple bonds which are conjugated to the triphenylene nucleus are particularly preferred. In addition, radicals which have a polymerizable group P are also suitable as further radicals R ¹ to R ⁵ . These radicals R ¹ to R ⁵ preferably have a structure of the formula III

—Γ3 — A ^I —Y ⁴ —P III,

where the variables have the following meaning:

Y ³ , Y ^{4 is} a chemical bond, oxygen, sulfur or a group —CO — 0—, —0 — CO—, —N (R) —CO— or —CO — NCR) -,

A ^{1 is} an alkylene group with 2 to 20 C atoms, in which non-adjacent C atoms can be replaced by oxygen, sulfur, CO — 0—, —0 — CO—, or —N (R) -,

P is a polymerizable group of the formula

CH ₃ Cl R CH = CH ₂ , C — CH ₂ C = CH ₂ • C = CH ₂ -

0 CH ₂ - CH = CH ₂ , —CH = CH— CH ₃ or - _c -CH ₂ and

R has the meaning given above.

The compounds are prepared by customary methods. The preparation of the differently substituted triphenylene derivatives is, for example, by W. reuder, H. Ringsdorf, Makromol. Chem. Rap. Commun, 4, 807 (1983) and in the earlier German patent application 19517208.6. The introduction of pre-spacers and polymerizable groups can be carried out analogously to literature regulations, such as are described, for example, in DE-A-39 17 196 and the literature cited therein.

The triphenylene derivatives of the formula I according to the invention are suitable as organic charge transport compounds and photoconductors and can be used, for example, in photocopiers, laser printers and laser fax machines, in electrochemical and photo-electrochemical cells and electronic components and in compensation layers of optical display devices. Examples

The examples are synthesized according to the instructions given. The phase behavior was determined by polarization microscopy in a Leitz polarization microscope (Leitz Ortholux II ^® ) in connection with a Mettler heating table. The optically determined phase sequence was verified by differential scanning calorimetry with a Mettler DSC 7.

The photoconductive properties were determined in an apparatus as described in Closs et al. (Liquid Crystals, 14 (3), 629 (1993)). The following abbreviations are used throughout:

I isotropic phase

D o discotic hexagonal phase

K ¹ , K ₂ , K different crystalline phases G glass state

example 1

2- (10 'bromo) decyloxy-3, 6, 7, 10, 11 pentakis (pentyloxy) - triphenylene da)

15 g (49.98 mmol) 1, 10-dibromodecane and 5 g (7.41 mmol) 3, 6, 7, 10, 11-pentakispentyloxy-2-hydroxy-triphenylene are dissolved in 12 ml pentanone-2 and after addition of 6 g (43.41 mmol) of potassium carbonate was stirred at 70 ° C. for 15 h. Thereafter, the reaction mixture is allowed to cool, and the precipitated potassium bromide and excess potassium carbonate are suctioned off. After the first flash chromatography (CH C1 ₂ / PE 1/2), a crude product is obtained which is subjected to a further flash chromatography. Recrystallization from acetonitrile / acetone (1/1) gives the pure product la.

Yield: 5.21 g b) Connection 1

1.5 g (2.22 mmol) of monohydroxytriphenylene and 2.0 g (2.24 mmol) of compound la are dissolved in 15 ml of methyl propyl ketone under argon. After adding 4 g (28.94 mmol) of potassium carbonate and the potassium iodide (50 mg), the mixture is heated to boiling for 20 h. After the reaction mixture has cooled, the product is filtered off with suction. The dimer is isolated by twice flash chromatography (CH ₂ CI2 / PE 1/1) and subsequent recrystallization from acetone.

Yield: 2.58 g

Example 2

a)

5 g (6.97 mmol) 3,6,7,10, ll-pentakispentyloxy-2-acetyloxy-triphenylene and 1.41 g (10.46 mmol) 4-bromobutene are dissolved in 10 ml toluene. After adding 2 g (35.71 mmol) of potassium hydroxide and 0.2 ml of tetrabutylammonium hydroxide, the mixture is stirred at 40 ° C. for 20 h. It is then filtered with 50 ml of water and 50 ml of petroleum ether. The organic phase is extracted with 2N H ₂ S0 ₄ saturated NaCl solution and water. By drying over sodium sulfate and distilling off the solvents, the crude product is obtained, which can be purified by repeated recrystallization from ethanol or acetonitrile. For highly pure product, flash chromatography (CH ₂ CI ₂ / PE 1/1) is carried out before recrystallization.

Yield: 4.33 g b)

200 mg (0.274 mmol) of compound ___ and 18.42 mg (0.137 mmol) of tetramethyldisiloxane are dissolved in a polymerization vessel under argon in 1 ml of absolute toluene. After the addition of the catalyst (2 μl SLM 86005, catalyst solution from Wacker Chemie Burghausen), the mixture is stirred at 50 ° C. for 48 h. It is then precipitated in 100 ml of toluene. The crude product obtained is subjected to flash chromatography (CH ₂ Cl ₂ / PE 1/1) in order to separate off the excess monomer. In conclusion, that will

Dimers dissolved in 1 ml methylene chloride, filtered through a white rim filter (pore diameter = 0.2 μ) and precipitated in 100 ml methanol.

Yield: 65 mg

Phase behavior: D _h0 110 i

Example 3

OC5H ₁ 1 OC5H11

200 mg (0.274 mmol) of compound 2__ and 28 mg (0.137 mmol) of hexamethyltrisiloxane are dissolved in a polymerization vessel under argon in 1 ml of absolute toluene. After adding the catalyst (2 μl SLM 86005, catalyst solution from Wacker Chemie Burghausen), the mixture is stirred at 60 ° C. for 48 h. It is then precipitated in 100 ml of toluene. The crude product obtained is subjected to flash chromatography (CH C1 ₂ / PE 1/1) to remove the excess monomer subject. Finally, the dimer is dissolved in 1 ml of methylene chloride, filtered through a white rim filter (pore diameter = 0.2 μm) and precipitated in 100 ml of methanol.

Yield: 149 mg

Phase behavior: ki 7 k ₂ 27.5 D _h0 90 i

Example 4

OC5H11

500 mg (0.68 mmol) of compound 2a and 41.23 mg (1.71 mmol) of tetramethylcyclosiloxane are dissolved in a polymerization vessel under argon in 1 ml of absolute toluene. After adding the catalyst (2 μl SLM 86005, catalyst solution from Wacker Chemie Burghausen), the mixture is stirred at 60 ° C. for 24 h. It is then precipitated in 100 ml of toluene. The crude product obtained is subjected to flash chromatography (CH2Cl2 / PE 3/1) to remove the excess monomer. Finally, the cyclosiloxane is dissolved in 1 ml of methylene chloride, filtered through a white rim filter (pore diameter = 0.2 μm) and precipitated in 100 ml of methanol.

Yield: 402.2 mg

Phase behavior: g - 48 D _h o 141 i

Example 5

OC ₅ H _n The following were used as in Example 2a:

6 g (8.37 mmol) 3, 6,7,10, ll-pentakispentyloxy-2-acetyloxy-triphenylene 3 g (15.7 mmol) 8-bromoctene

2 g (35.71 mmol) potassium hydroxide 0.2 ml tetrabutylammonium hydroxide

The reaction and working up corresponded to the procedure given in Example 2a).

Yield: 5.29 g

400 mg (0.509 mmol) of compound 5 and 30.63 mg (1.27 mmol) of tetramethylcyclosiloxane are dissolved in a polymerization vessel under argon in 1 ml of absolute toluene. After adding the catalyst 2 μl SLM 86005, the mixture is stirred at 60 ° C. for 18 h. It is then precipitated in 100 ml of toluene. The received

Crude product is subjected to flash chromatography (CH ₂ CI ₂ / PE 3/1) to remove the excess monomer. Finally, the cyclosiloxane is dissolved in 1 ml of methylene chloride, filtered through a white rim filter (pore diameter = 0.2 μ) and precipitated in 100 ml of methanol.

Yield: 357 mg phase behavior: g - 50 D _x 98.5 i Example 6

a)

OC5H11

1.88 g (2.79 mmol) monohydroxytriphenylene, 0.51 g (2.79 mmol) 6-bromohexanol, 1.07 g (8.37 mmol) finely powdered, freshly annealed potassium carbonate and 0.46 g (2, 79 mmol) of potassium iodide in 25 ml of 2-pentanone are heated under reflux under argon for 2 days. The cooled mixture is filtered, washed with dichloromethane and the crude product obtained is purified by flash chromatography twice (CH ₂ C1 ₂ ).

Yield: 1.52 g

b)

30 mg (0.0354 mmol) 2,3,6,7,10, 11-hexakis (ethoxycarbonyl-methyleneoxy) triphenylene and 246.9 mg (0.3185 mmol) compound are added after adding a little dry dichloro mixed methane (molecular sieve 4Ä) in a Schlenk vessel. The homogeneous solution is stirred for a few minutes and then the solvent is driven off as completely as possible with nitrogen (dried over P ₂ O ₅ ). The apparatus is briefly flushed with argon (dried over P ₂ O ₅ ) and heated to 110 ° C. Also under argon are 2 drops of the catalyst solution (10% by volume of tetra (isopropyl) orthotitanate (Merck) in dry diethenglycol dimethyl ether (molecular sieve 4 A) added to the melt. The beginning of the development of bubbles indicates the escape of ethanol and thus the start of the transesterification. It becomes one hour 120 ° C under normal pressure, 1.5 h at 125 ° C in a water jet vacuum and 12 h in an oil pump vacuum (0.007 bar), the temperature having to be raised to 140 ° C after one hour in an oil pump vacuum in order to freeze the melt Although an isolated formation of bubbles which suggests that the reaction has not been completely completed can be observed, the condensation is terminated after a total of 15 hours.

The residue is dissolved in absolute THF and the heptamer from the excess monomer via preparative GPC

Triphenylene alcohol separated (column material Sephadex LH 60, eluent = THF distilled over potassium). The desired product is obtained with the first high-intensity peak. Immediately afterwards, the elugram has several, very low-intensity peaks which cannot be assigned to fully converted low-molecular-weight oligomers; the excess triphenylene alcohol is eluted last. The heptamer is obtained as pure substance by spinning in the corresponding fractions. Since residues of THF are still occluded in the glassy oligomer even after drying for several days in an oil pump vacuum, freeze-drying must be carried out from benzene in order to remove the remaining THF.

Yield: 154.8 mg

Example 7

The reaction was carried out analogously to Example 6.a) Approach:

10.087 g (14.94 mmol) 3, 6, 7, 10, 11-pentakispentyloxy-2-hydroxy-triphenylene

3.334 g (14.94 mmol) 9-bromononanol

6.2 g (44.85 mmol) potassium carbonate

2.48 g (2.09 mmol) potassium iodide 40 ml pentanone-2

Yield: 7.61 g

Batch: 71.10 mg (0.0846 mmol) 2,3,6,7,10, 11-hexakis (ethoxy carbonyl-methyleneoxy) riphenylene 510.4 mg (0.6246 mmol) compound 7

5 drops of catalyst solution (10% by volume tetra (isopropyl) orthotitanate in dry diethylene glycol diethyl ether (molecular sieve 4 A). The reaction was carried out analogously to Example 6.b), but at a somewhat elevated temperature.

Yield: 428.8 mg Example 8

OC5H11

The reaction was carried out analogously to Example 6a).

Approach:

1.412 g (2.09 mmol) 3, 6.7.10, ll-pentakispentyloxy-2-hydroxy-triphenylene 0.525 g (2.09 mmol) 11-bromundecanol 0.87 g (6.27 mmol) potassium carbonate 0.347 g ( 2.09 mmol) potassium iodide 25 ml pentanone-2

Yield: 1.28 g

£

The reaction was carried out analogously to Example 6b) at a slightly elevated temperature compared to that given in 6b). There were 20.0 mg (0.0236 mmol) 2,3,6,7,10,11-hexakis (ethoxy carbonyl-methyleneoxy) triphenylene [71.10 g]

174.2 mg (0.1572 mmol) of compound £ a

2 drops of catalyst solution (10 vol% tetra (isopropyl) orthotitanate in dry diethylene glycol dimethyl ether (molecular sieve 4 A)

used.

Yield: 120.1 mg

Example 9

50 ml of toluene and 0.6 ml (7.3 mmol) of pyridine were added to 4.7 g (7.3 mmol) of 3, 6,7,10, ll-pentakispentyloxy-2- (hydroxyethyloxy) triphenylene under nitrogen . 2.2 ml of a 1 M solution of 1,3,5-cyclohexanetricarboxylic acid chloride in toluene were added dropwise to this mixture at 0.degree. This mixture was stirred for 5 hours at room temperature and 2 hours at 40 ° C and then washed with water. The organic phase was dried with sodium sulfate. The solvent was distilled off under reduced pressure. The purification was carried out by column chromatography.

Yield: 3.4 g

Phase behavior: heating: K 105 D 150 I cooling: no crystallization Example 10

OC ₅ H ₁₁ OC5H11 lü

Analogously to Example 9, the example compound ___ was obtained by reaction with 1, 3, 5-benzenetricarboxylic acid. manufactured.

For application examples 11 to 13, the discotically liquid-crystalline compounds between two indium tin oxide (ITO) coated glass plates were prepared. The electrode area is 2 * 2 mm ² . The layer thickness of the sample is approx. 10 μ, set by a spacer film of 6 μm. A voltage of 9 V is applied to this cell. The temperature of the sample takes place in a special heating table operated with direct current. For photocurrent measurement, the sample is exposed to a periodic light signal with a frequency of 10 Hz and the difference between light and dark current is measured using the lock-in technique. 17th

Example 11

For this example, the compound from Example 1 was prepared in accordance with the general instructions given above and examined for photoconductive properties. The result is summarized in Table 1.

Table 1

Temperature [° C] photocurrent [pA] phase

50 91 Dho

60 88 //

70 86

80 86

90 88 n

100 91

110 94

120 85

130 16 D o

135 8 I

Example 12

For this example, the compound from Example 2 was prepared in accordance with the general instructions given above and examined for photoconductive properties. The result is summarized in Table 2.

Table 2

Temperature [° C] photocurrent [pA] phase

30 95 DhO

40 58

50 38

55 35 n

60 33

65 33 n

70 35 n

75 36

80 36

85 37 n

90 16 Dho

91 5 I Example 13

For this example, the compound from Example 4 was prepared in accordance with the general instructions given above and examined for photoconductive properties. The result is summarized in Table 3.

Table 3

Temperature [° C] photocurrent [pA] phase

25 1648 Dho

30 1571

35 1615

40 1604

45 1473

50 1220

55 1033 //

60 758

65 549

70 429 a

75 357 n

80 330

90 308

100 296

110 308

120 247

130 209 Dho

135 44 I

Claims

1. Compounds of the general formula I

5

Z [—γi— (A — Y) _m —X] _n I,

in which the variables have the following meaning:

0 Z is an n-valent aliphatic radical with 2 to

20 carbon atoms or an n-valent three- to seven-membered saturated or unsaturated carbocyclic or heterocyclic residue, which can also be benzo-fused or an n-valent siloxane 5 or cyclosiloxane residue with up to 10 Si atoms,

Y ¹ , Y ^{2 is} a chemical bond, oxygen, sulfur or a group —CO — 0—, —0 — CO—, —N (R) - or —CO — N (R) -, 0 m 0 or 1,

A is an alkylene group with 2 to 20 C atoms, in which non-adjacent C atoms can be replaced by oxygen, sulfur, 5 —CO — 0—, —0 — CO—, or - (R) -,

n 2 to 6,

0 R is hydrogen or Cχ-C ₄ alkyl and

X is a substituted triphenylene radical,

where A, Y ¹ , Y ² , m and X, because they occur n times in the compounds 5, can be the same or different.

2. Compounds according to claim 1, in which Z represents a substituted or unsubstituted triphenylene radical.

°

3. Compounds according to claim 1, in which Z represents a linear or branched alkylene group having 2 to 20 C atoms.

5

4. Compounds according to claim 1, in which Z is a siloxane group of the formula

in which r represents a number from 1 to 9, or a cyclosiloxane group of the formula

in which s stands for a number from 3 to 6 means.

5. Compounds according to claims 1 to 4, in which X triphenylene radicals of the formula II

are, in which the radicals R ¹ to R ⁵ are identical or different Cι-C ₂ crAlkylreste, _{Cι-C2o-alkoxy,} Cι-C ₂ o-alkylthio, Cι-C o-alkanoyl, _{Cι-C2o-alkenyl} radicals , Cχ-C ₂ o-alkynyl radicals, fluorine, chlorine, bromine, iodine, cyano or nitro mean, the carbon chains in these ^' radicals also by non-neighboring oxygen or sulfur atoms or by COO, OCO or N (R) Groups can be interrupted.

6. Compounds according to claim 5, in which one or more of the radicals R ¹ to R ^{5 is} a polymerizable group of the general formula III

—Y ³ —Al — Y —P III

mean, where the variables have the following meaning:

Y ³ , Y ^{4 is} a chemical bond, oxygen, sulfur or a group —CO — 0—, —0 — CO—, - (R) —CO— or —CO — N (R) -,

A ^{1 is} an alkylene group with 2 to 20 C atoms, in which non-adjacent C atoms can be replaced by oxygen, sulfur, —co — 0—, —0 — CO—, or - (R) -,

P is a polymerizable group of the formula

CH ₃ Cl CH = CH ₂ , C = CH ₂ C = CH ₂ • C = CH ₂ ,

O CH ₂ CH = CH ₂ , CH = CH CH ₃ or c -CH ₂ and

R R has the meaning given in claim 1.

7. Use of the compounds according to claims 1 to 6 as charge transport compounds.

8. Use of the compounds according to claims 1 to 6 as charge transport compounds in photocopiers, laser printers and laser fax machines.

9. Use of the compounds according to claims 1 to 6 in electrochemical cells, photoelectrochemical cells and electronic components.

10. Use of the compounds according to claims 1 to 6 in compensation layers of optical display devices.