Thiadiazoloquinoxaline derivatives

Abstract

The present invention relates to thiadiazoloquinoxaline derivatives of the formula I, ##STR00001##
in which R.sup.11, R.sup.12, A.sup.11, A.sup.12, A.sup.21, A.sup.22, Z.sup.11, Z.sup.12, Z.sup.21, Z.sup.22, W, X.sup.11, X.sup.12, r and s have the meanings indicated in Claim 1, to processes and intermediates for the preparation thereof, to the use of the compounds of the formula I for optical, electro-optical and electronic purposes, in particular in liquid-crystal media and in devices for regulating the passage of energy from an outside space into an inside space, and to these LC media and the devices comprising these media.

Claims

1. A guest-host liquid crystalline medium comprising a dye component A) which comprises one or more compounds of the formula I and a liquid-crystalline component B) which comprises one or more mesogenic compounds ##STR00199## in which W denotes S or Se, X.sup.11, X.sup.12, identically or differently, denote H, alkyl having 1-6 C atoms, in which one or more H atoms may be replaced by F and one or more CH.sub.2 groups may be replaced by O or S in such a way that no O or S atoms are adjacent, perfluoroalkyl having 1-6 C atoms, halogen, CN, SF.sub.5, an aryl or heteroaryl group, which may be substituted by one or more radicals L, and alternatively the groups X.sup.11 and X.sup.12 together also denote a straight-chain or branched alkylene group having 2 to 10 C atoms, in which one, several or all H atoms may be replaced by F, R.sup.11, R.sup.12, identically or differently, denote F, straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced, independently of one another, by C(R.sup.z)C(R.sup.z), CC, N(R.sup.z), O, S, C(O), C(O)O, OC(O) or OC(O)O in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, R.sup.z on each occurrence, identically or differently, denotes H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by O, S, C(O), C(O)O, OC(O) or OC(O)O in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F or Cl, A.sup.11, A.sup.12 each, independently of one another, denote an aryl or heteroaryl group, which may be substituted by one or more radicals L, A.sup.21, A.sup.22 are each, independently of one another, defined like A.sup.11 or denote a cyclic alkyl group having 3 to 10 C atoms, in which 1 to 4 CH.sub.2 groups may be replaced by O in such a way that no two O atoms are adjacent, L on each occurrence, identically or differently, denotes OH, CH.sub.2OH, F, Cl, I, CN, NO.sub.2, SF.sub.5, NCO, NCS, OCN, SCN, C(O)N(R.sup.z).sub.2, C(O)R.sup.z, N(R.sup.z).sub.2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, Z.sup.11, Z.sup.12 on each occurrence, identically or differently, denote a single bond, CR.sup.x1CR.sup.x2, CC or C(O), Z.sup.21, Z.sup.22 are on each occurrence, identically or differently, defined like Z.sup.11 or denote O, S, CR.sup.y1R.sup.y2, CF.sub.2O, OCF.sub.2, C(O)O, OC(O), OC(O)O, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2S, SCF.sub.2, (CH.sub.2).sub.n1, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, (CF.sub.2).sub.n1, CHCHCOO or OCOCHCH, R.sup.x1, R.sup.x2, independently of one another, denote H, F, Cl, CN or alkyl having 1-12 C atoms, R.sup.y1, R.sup.y2 each, independently of one another, denote H or alkyl having 1-12 C atoms, r, s, independently of one another, denote 0, 1, 2 or 3, n1 denotes 1, 2, 3 or 4, with the proviso that the compound of the formula ##STR00200## is excluded.

2. A liquid crystalline medium according to claim 1, wherein in formula I, if r and s are identical, at least one of the groups A.sup.11 and A.sup.12, or R.sup.11 and R.sup.12, or A.sup.21 and A.sup.22, or Z.sup.11 and Z.sup.12, or Z.sup.21 and Z.sup.22, or X.sup.11 and X.sup.12 is different from one another, where the parameters have the meanings indicated in claim 1.

3. A liquid crystalline medium according to claim 1, wherein in formula I, r denotes 0, 1 or 2 and s denotes r+1.

4. A liquid crystalline medium according to claim 1, wherein in formula I, W denotes S.

5. A liquid crystalline medium according to claim 1, wherein in formula I, X.sup.11 and X.sup.12 each, independently of one another, denote H, CH.sub.3, C.sub.2H.sub.5, F, Cl, CF.sub.3, OCF.sub.3, CN or together denote 1,4-butylene, 1,3-hexafluoropropylidene or 1,4-octafluorobutylidene.

6. A liquid crystalline medium according to claim 1, wherein in formula I, A.sup.11, A.sup.12, A.sup.21, A.sup.22 are selected on each occurrence, identically or differently, from groups, optionally substituted by radicals L, derived from the parent substances benzene, fluorene, naphthalene, pyridine, pyrimidine, thiophene, thiazole, dihydrothienodioxin, benzothiophene, dibenzothiophene, benzodithiophene, cyclopentadithiophene, thienothiophene, indenothiophene, furan, benzofuran, dibenzofuran and quinoline, where L is selected from the groups F, Cl, CN, NO.sub.2, CH.sub.3, C.sub.2H.sub.5, OCH.sub.3, OC.sub.2H.sub.5, COCH.sub.3, COC.sub.2H.sub.5, COOCH.sub.3, COOC.sub.2H.sub.5, CF.sub.3, OCF.sub.3, OCHF.sub.2, OC.sub.2F.sub.5 and phenyl.

7. A liquid crystalline medium according to claim 1, wherein the compounds of formula I, are selected from the following sub-formulae: ##STR00201## ##STR00202## ##STR00203## ##STR00204## in which R.sup.11, R.sup.12, independently of one another, denote F, a straight-chain alkyl or alkoxy group having 1 to 15 C atoms or a branched alkyl or alkoxy group having 3 to 20 C atoms, in which, in addition, one or more H atoms may be replaced by F, A.sup.11, A.sup.12, A.sup.21, A.sup.22 each, independently of one another, denote 1,4-phenylene, 2,6-naphthylene, thiophene-2,5-diyl or thiazole-2,5-diyl, Z.sup.21, Z.sup.22, independently of one another, denote CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, CHCH, CFCF, OCH.sub.2, CH.sub.2O, OCF.sub.2, CF.sub.2O or a single bond, L on each occurrence, identically or differently, denotes OH, CH.sub.2OH, F, Cl, I, CN, NO.sub.2, SF.sub.5, NCO, NCS, OCN, SCN, C(O)N(R.sup.z).sub.2, C(O)R.sup.z, N(R.sup.z).sub.2, optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, a, independently of one another, denotes 0, 1, 2, 3 or 4, b, independently of one another, denotes 0, 1 or 2, c, independently of one another, denotes 0 or 1, and d, independently of one another, denotes 1, 2, 3, 4, 5 or 6.

8. A liquid crystalline medium according to claim 1, wherein in formula I, Z.sup.21 and Z.sup.22 denote a single bond.

9. A method which comprises including a liquid crystalline medium according to claim 1 in electro-optical displays, devices for regulating the passage of energy from an outside space into an inside space, electrical semiconductors, organic field-effect transistors (OFETs), printed circuits, radio frequency identification elements (RFIDs), organic light-emitting diodes (OLEDs), lighting elements, photovoltaic devices, optical sensors, effect pigments, decorative elements or as dye for colouring polymers.

10. A process wherein compounds of the formula III are converted into compounds of the formula I according to claim 1, ##STR00205## in which W, R.sup.11, R.sup.12, A.sup.11, A.sup.12, A.sup.21, A.sup.22, Z.sup.11, Z.sup.12, Z.sup.21, Z.sup.22, r and s have the meanings indicated for formula I in claim 1.

11. A process for the preparation of the LC media according to claim 1, wherein two or more mesogenic compounds are mixed with one another, and one or more dyes of the formula I are added in a further process step.

12. A device for regulating the passage of energy from an outside space into an inside space, where the device contains a switching layer comprising an LC medium according to claim 1.

13. A window containing a device according to claim 12.

Description

EXAMPLES

(1) The present invention is described in detail by the following, non-restrictive example.

(2) All physical properties are determined in accordance with Merck Liquid Crystals, Physical Properties of Liquid Crystals, Status November 1997, Merck KGaA, Germany, and apply for a temperature of 20 C. The value of n is determined at 589 nm, and the value of is determined at 1 kHz, unless explicitly indicated otherwise in each case. n.sub.e and n.sub.o are in each case the refractive indices of the extraordinary and ordinary light beam under the conditions indicated above.

(3) The degree of anisotropy R is determined from the value for the extinction coefficient E(p) (extinction coefficient of the mixture in the case of parallel alignment of the molecules to the polarisation direction of the light) and the value for the extinction coefficient of the mixture E(s) (extinction coefficient of the mixture in the case of perpendicular alignment of the molecules to the polarisation direction of the light), in each case at the wavelength of the maximum of the absorption band of the dye in question. If the dye has a plurality of absorption bands, the strongest absorption band is selected. The alignment of the molecules of the mixture is achieved by an alignment layer, as known to the person skilled in the art in the area of LC display technology. In order to eliminate influences by liquid-crystalline medium, other absorptions or reflections, each measurement is carried out against an identical mixture comprising no dye, and the value obtained is subtracted.

(4) The measurement is carried out using linear-polarised light whose vibration direction is either parallel to the alignment direction (determination of E(p)) or perpendicular to the alignment direction (determination of E(s)). This can be achieved by a linear polariser, where the polariser is rotated with respect to the device in order to achieve the two different vibration directions. The measurement of E(p) and E(s) is thus carried out via the rotation of the vibration direction of the incident polarised light.

(5) The degree of anisotropy R is calculated from the resultant values for E(s) and E(p) in accordance with the formula
R=[E(p)E(s)]/[E(p)+2*E(s)],
as indicated, inter alia, in Polarized Light in Optics and Spectroscopy, D. S. Kliger et al., Academic Press, 1990. A detailed description of the method for the determination of the degree of anisotropy of liquid-crystalline media comprising a dichroic dye is also given in B. Bahadur, Liquid CrystalsApplications and Uses, Vol. 3, 1992, World Scientific Publishing, Section 11.4.2.

SYNTHESIS EXAMPLES

Example 1

4,9-Bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]thiophen-2-yl}-6,7-dimethyl-2-thia-1,3,5,8-tetraazacyclopenta[b]naphthalene [TDC-1]

1.1. 5,6-Dinitro-4,7-bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]thiophen-2-yl}-benzo-1,2,5-thiadiazole [12]

(6) ##STR00186##

(7) A carefully degassed mixture of 4-(3-ethylheptyl)-2-fluorobenzeneboronic acid (2.1 g, 7.7 mmol), 4,7-bis-(5-bromothiophen-2-yl)-5,6-dimethylbenzo-1,2,5-thiadiazole (2.0 g, 3.65 mmol), tris(dibenzylideneacetone)dipalladium(0) (37 mg, 0.04 mmol), tris(o-tolyl)phosphine (50 mg, 0.16 mmol), toluene (65 ml) and 2 M aqueous Na.sub.2CO.sub.3 solution (40 ml) is heated under reflux under an argon atmosphere for 18 h. The batch is allowed to cool, subjected to conventional work-up, and the crude product is purified by chromatography (SiO.sub.2; toluene/n-heptane 2:3). Subsequent crystallisation from toluene/n-heptane 1:1 gives 5,6-dinitro-4,7-bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]thiophen-2-yl}benzo-1,2,5-thiadiazole (11) as a yellowish solid.

1.2. 5,6-Diamino-4,7-bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]thiophen-2-yl}-benzo-1,2,5-thiadiazole [13]

(8) ##STR00187##

(9) A solution of 5,6-dinitro-4,7-bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]-thiophen-2-yl}benzo-1,2,5-thiadiazole (6.3 g, 7.5 mmol) in THF (65 ml) is hydrogenated in the presence of nickel sponge catalyst (Johnson-Matheson A-7000) at atmospheric pressure and room temperature until the equivalent amount of hydrogen has been taken up. Filtration and evaporation to dryness gives 5,6-diamino-4,7-bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]thiophen-2-yl}benzo-1,2,5-thiadiazole (13) as a brownish resin, which is employed in the next step without further purification.

1.3. 4,9-Bis-{5-[4-(3-ethylheptyl)-2-fluorophenyl]thiophen-2-yl}-6,7-dimethyl-2-thia-1,3,5,8-tetraazacyclopenta[b]naphthalene [TDC-1]

(10) ##STR00188##

(11) Diacetyl (1.3 ml, 15 mmol) is added to a solution of 13 (5.8 g, 7.5 mmol) in methanol (300 ml), and the mixture is heated under reflux for 18 h. The mixture is subjected to conventional aqueous work-up, and the crude product is purified by chromatography (SiO.sub.2; n-heptane/toluene 1:1). Subsequent crystallisation from n-heptane gives 5,6-diamino-4,7-bis-{5-[4-(3-ethyl-heptyl)-2-fluorophenyl]thiophen-2-yl}benzo-1,2,5-thiadiazole as a blue solid of m.p. 160 C.

(12) The following compounds are obtained analogously to Example 1:

(13) ##STR00189## ##STR00190## ##STR00191## ##STR00192## ##STR00193## ##STR00194## ##STR00195## ##STR00196##

USE EXAMPLES

(14) The dyes prepared are investigated with respect to their physical properties in order to establish their suitability for use in devices for regulating energy transmission. For comparison, the corresponding properties for compounds D-1 and D-2 (structure see below) are indicated.

(15) Preparation of Liquid-Crystalline Dye Mixtures

(16) An LC base mixture G-1 is prepared as follows:

(17) TABLE-US-00007 CPG-3-F 5% Clearing point [ C.] 114.5 CPG-5-F 5% n 0.1342 CPU-3-F 15% n.sub.e 1.6293 CPU-5-F 15% n.sub.o 1.4951 PCH-3 16% PCH-5 16% CCGU-3-F 7% CGPC-3-3 4% CGPC-5-3 4% CGPC-5-5 4% CCZPC-3-3 3% CCZPC-3-4 3% CCZPC-3-5 3%

(18) The following dyes in the proportions indicated are dissolved in base mixture G-1:

Mixture Example M-1

(19) TABLE-US-00008 G-1 99.75% TDC-1 0.25%

(20) Correspondingly, mixtures M-2 to M-7 are obtained from in each case 99.75% of base mixture G-1 and in each case 0.25% of the dyes TDC-3, TDC-7, TDC-21, TDC-28, TDC-36 and TDC-39.

(21) A Comparative Mixture V-1 is Prepared as Follows:

(22) TABLE-US-00009 G-1 99.75% D-1 0.25%

(23) Mixture Example M-8 is Prepared as Follows:

(24) TABLE-US-00010 G-1 99.75% D-2 0.25% TDC-41 1.00%

(25) Structures of the further dyes used:

(26) TABLE-US-00011 TABLE 2 D-1 D-2

(27) Table 3 shows absorption maximum, degree of anisotropy and solubility of the dyes TDC-1, TDC-3, TDC-7, TDC-21, TDC-28, TDC-36 and TDC-39. The absorption maximum of comparative substance D-1 is comparable to that of TDC-1.

(28) TABLE-US-00012 TABLE 3 Absorption Solubility in maximum/ Degree of % by weight Dye Mixture nm anisotropy R in M-1 TDC-1 M-1 679 0.69 >1.00 TDC-3 M-2 676 0.71 TDC-7 M-3 670 0.71 TDC-21 M-4 705 0.70 TDC-28 M-5 694 0.65 TDC-36 M-6 742 0.67 TDC-39 M-7 777, 0.67 420 0.63 D-1 V-1 675

(29) FIG. 1 shows the UV-VIS spectrum of dyes TDC-1 and D-1, measured in base mixture G-1.

(30) The measurements show that the thiadiazoloquinoxaline compounds according to the invention have excellent properties with respect to degree of anisotropy and solubility in liquid-crystalline media. Comparison of the UV-VIS spectrum of TDC-1 (mixture M-1) with that of the rylene dye D-1 (mixture V-1), which has a comparable absorption range, additionally shows that no bands are present in the range 500-550 nm in the case of TDC-1. This enables applications to be achieved which remain significantly better within their colour type, i.e. bright and dark are closer in their colour types on use of TDC-1 than on use of D-1. Furthermore, the narrower band also enables significantly better colour saturations to be achieved.

(31) Use of Liquid-Crystalline Media Comprising the Dyes in Devices for Regulating the Passage of Energy

(32) In order to produce the device, liquid-crystal mixture M-8 is introduced into the interspace of the following layer arrangement: substrate layer ITO layer polyimide alignment layer interspace held open using spacers polyimide alignment layer ITO layer substrate layer.

(33) The liquid-crystal layer in this arrangement is aligned in a planar manner with antiparallel pretilt angle. This alignment is achieved by two polyimide layers rubbed antiparallel to one another. The thickness of the liquid-crystalline layer is defined by spacers and is usually 25 m.

(34) Values for the degree of light transmission .sub.v for both the dark and bright switching states of the device are determined and are shown below. The bright switching state is achieved by application of a voltage, while the dark switching state is present without voltage. Furthermore, the colour location of the device (in CIE coordinates) in the dark and bright states is determined.

(35) The measurement is carried out with the device comprising the liquid-crystalline medium with dyes in the measurement beam and a device of the same construction correspondingly without the dyes in the reference beam. Reflection and absorption losses of the cell are thereby eliminated.

(36) The value .sub.v and the CIE coordinates (x,y) are defined as follows: .sub.v=degree of light transmission, determined in accordance with DIN EN410

(37) The colour location (for white, grey, black) of the basic standard illuminant D65 here is at x=0.3127 and y=0.3290 (Manfred Richter, EinfUhrung in die Farbmetrik [Introduction to Colorimetry], second edition 1991, ISBN 3-11-008209-8). The colour locations (x,y) indicated all relate to the standard illuminant D65 and the 2 standard observer in accordance with CIE 1931.

(38) Measurement values obtained for the device (double cell): dark state: x=0.148; y=0.160; .sub.v=12.6% bright state: x=0.256; y=0.305; .sub.v=56.5%

(39) Good stability of the liquid-crystalline medium and good solubility of the dyes in the liquid-crystalline medium are evident in the example.

(40) Furthermore, the example shows that the device can be switched from a dark state having significantly lower light transmission to a bright state having significantly increased light transmission by application of a voltage.

(41) It is furthermore observed that, by means of dye TDC-1 in combination with dye D-2, a mixture having particularly good colour saturation in the blue is obtained.

BRIEF DESCRIPTION OF DRAWING

(42) FIG. 1 is a graph.