LIQUID CRYSTALLINE MEDIUM

Abstract

The present invention relates to liquid crystalline media comprising one or more benzothiadiazol derivatives of 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 the use of such liquid crystal media for optical, electro-optical and electronic purposes, in particular in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.

Claims

1. Liquid crystalline medium comprising a dye component A) comprising one or more compounds of formula I, ##STR00414## and a liquid-crystalline component B) comprising one or more mesogenic compounds, wherein in formula I of componen A) W denotes S, Se or O, R.sup.11, R.sup.12 identically or differently, denote H, 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, CO, COO, OCO or OCOO 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, CO, COO, OCO or OCOO 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 one or more 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, Br, 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, an aryl or heteroaryl group, which may be substituted by one or more radicals L, and alternatively two adjacent groups L 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 and in which one or more CH.sub.2CH.sub.2 groups can be replaced by CHCH, 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.

2. Liquid crystalline medium according to claim 1, characterised in that one or more compounds of formula I are selected from the compounds of formulae IA and IB ##STR00415## wherein the occurring groups and parameters have the meaning indicated for formula I.

3. Liquid crystalline medium according to claim 1, characterised in that it comprises one or more compounds of formula IA selected from the group of compounds of the sub-formulae IA-1 to IA-3 ##STR00416## wherein Z.sup.21, Z.sup.22 on each occurrence, identically or differently, denote a single bond, CR.sup.x1CR.sup.x2, CC or C(O).

4. Liquid crystalline medium according to claim 1, characterised in that A.sup.11 and A.sup.12 denote, independently of one another, 1,4-phenylene, 1,4-naphthylene, 2,6-naphthylene, thiazole-2,5-diyl, thiophene-2,5-diyl or thienothiophene-2,5-diyl, wherein one or more H atoms may be replaced by a group L.

5. Liquid crystalline medium according to claim 1, characterised in that it comprises one or more compounds of formula I wherein Z.sup.21 and Z.sup.22 denote a single bond.

6. Liquid crystalline medium according to claim 1, characterised in that it comprises one or more compounds of formula I wherein R.sup.11 and R.sup.12 denote a branched alkyl group having 3 to 25 C atoms, in which one or more H atoms can be replaced by F, one or more CH.sub.2 groups can be replaced by O and/or NH and one or more CH groups can be replaced by N.

7. Liquid crystalline medium according to claim 1, characterised in that it has negative dielectric anisotropy and comprises one or more compounds selected from the group of compounds of formulae CY, PY and AC ##STR00417## wherein ##STR00418## denotes ##STR00419## denote ##STR00420## denotes ##STR00421## R.sup.1, R.sup.2, R.sup.AC1, R.sup.AC2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by O, CHCH, CO, OCO or COO in such a way that O atoms are not linked directly to one another, Z.sup.x, Z.sup.y, Z.sup.AC each, independently of one another, denote CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, CFCF, CHCHCH.sub.2O or a single bond, L.sup.1-4 each, independently of one another, denote F, Cl, CN, OCF.sub.3, CF.sub.3, CH.sub.3, CH.sub.2F, CHF.sub.2. a is 1 or 2, b is 0 or 1, c is 0, 1 or 2, d is 0 or 1.

8. Liquid crystalline medium according to claim 1, characterised in that it has positive dielectric anisotropy and comprises one or more compounds selected from the group of compounds of formulae II to VIII ##STR00422## wherein ##STR00423## each, independently of one another, denote ##STR00424## R.sup.20 each, identically or differently, denote a halogenated or unsubstituted alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00425## OO or OCO in such a way that 0 atoms are not linked directly to one another, X.sup.20 each, identically or differently, denote F, Cl, CN, SF.sub.5, SCN, NCS, a halogenated alkyl radical, a halogenated alkenyl radical, a halogenated alkoxy radical or a halogenated alkenyloxy radical, each having up to 6 C atoms, and Y.sup.20-24 each, identically or differently, denote H or F; Z.sup.20 denotes C.sub.2H.sub.4, (CH.sub.2).sub.4, CHCH, CFCF, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CH.sub.2O, OCH.sub.2, COO or OCF.sub.2, in formulae V and VI also a single bond, in formulae V and VIII also CF.sub.2O, r denotes 0 or 1, and s denotes 0 or 1.

9. Liquid crystalline medium according to claim 1, characterised in that it additionally comprises one or more compounds selected from the group of compounds of formulae DK and O ##STR00426## wherein R.sup.5, R.sup.6, R.sup.O1 and R.sup.O2 each, independently of one another, denote alkyl having 1 to 12 C atoms, where, in addition, one or two non-adjacent CH.sub.2 groups may be replaced by O, CHCH, CO, OCO or COO in such a way that O atoms are not linked directly to one another, ##STR00427## denotes ##STR00428## denotes ##STR00429## denotes ##STR00430## denotes ##STR00431## Z.sup.O1 denotes CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, CC or a single bond, Z.sup.O2 denotes CH.sub.2O, C(O)O, CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, or a single bond, o is 1 or 2. e is 1 or 2.

10. Liquid crystalline medium according to claim 9, characterised in that it comprises one or more compounds of formula O, selected from the group of compounds of the sub-formulae O3 to O5 ##STR00432## wherein R.sup.O1 and R.sup.O2, identically or differently, denote straight-chain alkyl having 1 to 6 C atoms or straight-chain alkenyl having 2 to 6 C atoms.

11. Liquid crystalline medium according to claim 9, characterised in that it comprises one or more compounds of formula DK selected from the group of compounds of the sub-formulae DK1 to DK12: ##STR00433## in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2-6 C atoms.

12. In an electro-optical display, device regulating the passage of energy from an outside space into an inside space, electrical semiconductor, organic field-effect transistor (OFETs), printed circuit, radio frequency identification element (RFIDs), organic light-emitting diode (OLEDs), lighting element, photovoltaic device, optical sensor, effect pigment, decorative element or dye colouring a polymer comprising a liquid crystalline medium, the improvement wherein the liquid crystalline medium is one of claim 1.

13. Device for regulating the passage of energy from an outside space into an inside space, where the device contains a switching layer comprising a liquid crystalline medium according to claim 1.

14. Window containing a device according to claim 13.

15. Compound of formula I ##STR00434## wherein W denotes O, and R.sup.11, R.sup.12 identically or differently, denote H, 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, CO, COO, OCO or OCOO 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, CO, COO, OCO or OCOO 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, denoted 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 one or more 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, Br, I, CN, NO.sub.2, SF.sub.5, NCO, NCS, OCR, 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, an aryl or heteroaryl group, winch may be substituted by one or more radicals L, and alternatively two adjacent groups L 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 and in which one or more CH.sub.2CH.sub.2 groups can be replaced by CHCH, 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, or wherein the groups
R.sup.11A.sup.21-Z.sup.21.sub.rA.sup.11-Z.sup.11- and Z.sup.12-A.sup.12Z.sup.22-A.sup.22.sub.sR.sup.12 are different from one another, or R.sup.11 and R.sup.12, independently of one another, denote a branched alkyl group having 3 to 25 C atoms, in which one or more H atoms can be replaced by F, one or more CH.sub.2 groups can be replaced by O and/or NH and one or more CH groups can be replaced by N.

16. Compound according to claim 15, characterised in that R.sup.11 and R.sup.12, independently of one another, are selected from the group of radicals consisting of 2-ethylhexyl, 2-ethylheptyl, 2-ethyloctyl, 2-ethylnonyl, 2-ethyldecyl, 3-ethylhexyl, 3-ethylheptyl, 3-ethyloctyl, 3-ethylnonyl, 3-ethyldecyl and 2-octyldodecyl.

Description

EXAMPLES

[0402] The present invention is described in detail by the following, non-restrictive example.

[0403] 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.

[0404] 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 sub-tracted.

[0405] 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.

[0406] 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)],

[0407] 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.

[0408] Synthesis

Example 1: 4,8-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-benzo-[1,2-c;4,5c]bis[1,2,5]thiadiazole [BTD-1]

Step 1: 4,7-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-5,6-dinitro-2,1,3-benzothiadiazole [4]

[0409] ##STR00403##

[0410] A degassed mixture of 2 (2.1 g, 7.7 mmol), 3 (2.0 g, 3.65 mmol), tris(dibenzylidenacetone)dipalladium(0) (37 mg, 0.04 mmol), tris(o-tolyl)phosphine (50 mg, 0.16 mmol), toluene (65 mL) and 2 M aq. Na.sub.2CO.sub.3-solution (40 mL) are refluxed for 18 h under argon. The reaction is extracted with ether, the combined extracts are evaporated and the residue is purified by chromatography (SiO.sub.2; toluene/n-heptane 2:3) and recrystallised from toluene/n-heptane (2:3) to give 4,7-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-5,6-dinitro-2,1,3-benzothiadiazole (4) as a yellow solid.

Step 2: 4,7-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-5,6-diamino-2,1,3-benzothiadiazole [5]

[0411] ##STR00404##

[0412] A solution of 4 (6.3 g, 7.5 mmol) in THF (65 mL) is hydrogenated on Sponge-Nickel-catalyst (Johnson-Matheson A-7000) under normal pressure at room temp. until one equivalent of hydrogen is consumed. The reaction is filtered, evaporated and the residue is used in the next step without purification.

Step 3: 4,8-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-benzo[1,2-c;4,5c]bis[1,2,5]thiadiazole

[0413] ##STR00405##

[0414] To a solution of 5 (6.3 g, 8.0 mmol) in CH.sub.2Cl.sub.2 (100 mL), triethylamine (4.5 mL, 32.5 mmol) followed by thionyl chlorid (1.2 mL, 16.5 mmol) are added dropwise under ice cooling. The reaction is refluxed for 18 h, quenched with water, extracted with ether and the combined extracts are evaporated. The crude product is purified by chromatography (SiO.sub.2; toluene/n-heptane 1:1) and recrystallised from toluene/n-heptane 1:1 to yield 4,8-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-benzo[1,2-c;4,5c]bis[1,2,5]thiadiazole (BTD-1) as dark green crystals, m.p. 246 C.

Example 2. 4,7-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-6.SUP.4..SUP.2.-[1,2,5]thiadiazolo[3,4-f]-2,1,3-benzoxadiazole

[0415] ##STR00406##

[0416] Compound 6 is prepared by Suzuki coupling of 4,7-dibromo-5,6-dinitro-2,1,3-benzothiadiazole with 2-[4-[4-(3-ethylheptyl)-2-fluoro-phenyl]phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in analogy to procedures known from the literature, for example described in US 2013/0037784.

[0417] A solution of 6 (2.1 g, 2.53 mmol) in THF (20 mL) is hydrogenated on Sponge-Nickel-catalyst (Johnson-Matheson A-7000, 1 g) under normal pressure at room temp. until 0.75 equivalents of hydrogen are consumed. The intermediate product is oxidised by exposure to air, and the solution is filtered, evaporated and the residue is purified by column chromatography to yield 4,7-bis[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-6.sup.4.sup.2-[1,2,5]thiadiazolo[3,4-f]-2,1,3-benzoxadiazole (BOD-1), m.p. 178 C.

[0418] The following compounds are obtained analogously to Example 1 (BTD-1):

##STR00407## ##STR00408## ##STR00409##

[0419] The following compounds are obtained analogously to Example 2:

##STR00410## ##STR00411##

Use Examples

[0420] 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.

[0421] Preparation of Liquid-Crystalline Dye Mixtures

[0422] Nematic LC host mixtures N-1 to N-19 are prepared as follows:

TABLE-US-00008 Mixture N-1: Composition Compound No. Abbreviation c [%] Physical properties 1 CY-3-O2 12.0 T(N, I) [ C.] = 91.5 2 CY-5-O2 12.0 n (20 C., 589.3 nm) = 0.078 3 CCY-3-O2 13.0 (20 C., 1 kHz) = 3.7 4 CCY-5-O2 13.0 LTS (20 C.) [d] = 27 5 CCY-3-1 8.0 6 CCZC-3-3 4.0 7 CCZC-3-5 3.0 8 CCZC-4-3 3.0 9 CC-3-4 6.0 10 CC-3-5 6.0 11 CC-3-O3 8.0 12 CC-5-O1 4.0 13 CC-5-O2 4.0 14 CP-3-O2 4.0 100

TABLE-US-00009 Mixture N-2: Composition Compound No. Abbreviation c [%] Physical properties 1 CY-3-O2 12.0 T(N, I) [ C.] = 79.5 2 CY-5-O2 13.0 n (20 C., 589.3 nm) = 0.100 3 CCY-3-O2 11.0 (20 C., 1 kHz) = 3.1 4 CCY-5-O2 10.0 LTS (20 C.) [d] >42 5 CCY-2-1 9.0 6 CPP-3-2 6.0 7 CPP-5-2 4.0 8 CGP-3-2 6.0 9 CC-3-4 6.0 10 CC-3-5 6.0 11 CP-3-O2 17.0 100

TABLE-US-00010 Mixture N-3: Composition Compound No. Abbreviation c [%] Physical properties 1 CC(CN)-4-7 20.0 T(N, I) [ C.] = 100.5 2 CC(CN)-5-5 21.0 n (20 C., 589.3 nm) = 0.044 3 CC-3-O1 11.0 (20 C., 1 kHz) = 4.8 4 CC-5-O1 5.0 LTS (20 C.) [d] >42 5 CC-5-O2 5.0 6 CCZC-3-3 4.0 7 CCZC-3-5 4.0 8 CCZC-4-3 4.0 9 CCZC-4-5 4.0 10 CC(CN)C-5-5 22.0 100

TABLE-US-00011 Mixture N-4: Composition Compound No. Abbreviation c [%] Physical properties 1 CC(CN)-3-3 10.0 T(N, I) [ C.] = 106.0 2 CC(CN)-4-7 10.0 n (20 C., 589.3 nm) = 0.118 3 CC(CN)-5-7 10.0 (20 C., 1 kHz) = 6.0 4 CY-3-O2 5.0 LTS (20 C.) [d] >73 5 PPC(CN)-5-3 13.0 6 CCY-3-O2 5.0 7 CCY-3-O3 5.0 8 CCY-4-O2 6.0 9 CPY-2-O2 9.0 10 CPY-3-O2 8.0 11 PYP-2-3 7.0 12 PYP-2-4 6.0 13 CGPC-3-3 2.0 14 CGPC-5-3 2.0 15 CGPC-5-5 2.0 100

TABLE-US-00012 Mixture N-5: Composition Compound No. Abbreviation c [%] Physical properties 1 CC(CN)-3-3 8.0 T(N, I) [ C.] = 113.5 2 CC(CN)-4-7 8.0 n (20 C., 589.3 nm) = 0.127 3 CC(CN)-5-5 9.0 (20 C., 1 kHz) = 6.0 4 CY-3-O2 5.0 LTS (20 C.) [d] >100 5 PPC(CN)-5-3 12.0 6 CCY-3-O2 5.0 7 CCY-3-O3 5.0 8 CCY-4-O2 6.0 9 CPY-2-O2 9.0 10 CPY-3-O2 8.0 11 PYP-2-3 7.0 12 PYP-2-4 6.0 13 CGPC-3-3 2.0 14 CGPC-5-3 2.0 15 CGPC-5-5 2.0 16 CPP-3-2 3.0 17 CPP-5-2 3.0 100

TABLE-US-00013 Mixture N-6: Composition Compound No. Abbreviation c [%] Physical properties 1 CC(CN)-3-3 13.0 T(N, I) [ C.] = 107.5 2 CC(CN)-4-7 15.0 n (20 C., 589.3 nm) = 0.103 3 CC(CN)-5-5 12.0 (20 C., 1 kHz) = 4.9 4 PPC(CN)-5-3 10.0 LTS (20 C.) [d] >83 5 CPY-2-O2 5.0 6 CPY-3-O2 5.0 7 CCY-4-O2 5.0 8 PYP-2-3 10.0 9 CP-3-O1 8.0 10 CGPC-3-3 4.0 11 CGPC-5-3 3.0 12 CGPC-5-5 3.0 13 CCZPC-3-3 3.0 14 CCZPC-3-4 2.0 15 CCZPC-3-5 2.0 100

TABLE-US-00014 Mixture N-7: Composition Compound No. Abbreviation c [%] Physical properties 1 CC(CN)-4-7 10.0 T(N, I) [ C.] = 111.5 2 CC(CN)-5-5 10.0 n (20 C., 589.3 nm) = 0.124 3 CY-3-O2 6.0 (20 C., 1 kHz) = 4.7 4 CP-3-O1 10.0 LTS (20 C.) [d] >73 5 PPC(CN)-5-3 10.0 6 CPY-2-O2 7.0 7 CPY-3-O2 7.0 8 CCY-3-O2 6.0 9 CCY-5-O2 7.0 10 PYP-2-3 10.0 11 CGP-3-2 6.0 12 CGPC-3-3 3.0 13 CGPC-5-3 3.0 14 CGPC-5-5 2.0 15 CCZPC-3-3 3.0 100

TABLE-US-00015 Mixture N-8: Composition Compound No. Abbreviation c [%] Physical properties 1 CC(CN)-3-3 8.0 T(N, I) [ C.] = 107.5 2 CC(CN)-4-7 10.0 n (20 C., 589.3 nm) = 0.129 3 CC(CN)-5-5 10.0 (20 C., 1 kHz) = 5.5 4 CY-3-O2 10.0 LTS (20 C.) [d] >73 5 CPP(F,CN)-5-O2 10.0 6 CPY-2-O2 6.0 7 CPY-3-O2 9.0 8 CCY-4-O2 5.0 9 PYP-2-3 10.0 10 PYP-2-4 10.0 11 CGPC-3-3 3.0 12 CGPC-5-3 3.0 13 CGPC-5-5 3.0 14 CCZPC-3-3 3.0 100

TABLE-US-00016 Mixture N-9: Composition Compound No. Abbreviation c [%] Physical properties 1 CY-3-O2 9.0 T(N, I) [ C.] = 110.5 2 CY-3-O4 9.0 n (20 C., 589.3 nm) = 0.132 3 CY-5-O2 12.0 (20 C., 1 kHz) = 4.9 4 CY-5-O4 8.0 LTS (20 C.) [d] >76 5 CCY-3-O2 5.0 6 CCY-3-O3 5.0 7 CCY-4-O2 5.0 8 CPY-2-O2 7.0 9 CPY-3-O2 6.0 10 PYP-2-3 12.0 11 CCP-V-1 6.0 12 CCZPC-3-3 3.0 13 CCZPC-3-4 3.0 14 CGPC-3-3 5.0 15 CGPC-5-3 5.0 100

TABLE-US-00017 Mixture N-10: Composition Compound No. Abbreviation c [%] Physical properties 1 CC-3-V 41.5 T(N, I) [ C.] = 74.0 2 CCY-3-O1 5.0 n (20 C., 589.3 nm) = 0.101 3 CCY-3-O2 11.0 (20 C., 1 kHz) = 3.5 4 CCY-4-O2 6.0 LTS (20 C.) [d] 13 5 CPY-2-O2 5.0 6 CPY-3-O2 11.0 7 CY-3-O2 3.5 8 PY-3-O2 12.0 9 B-3-O2 5.0 100

TABLE-US-00018 Mixture N-11: Composition Compound No. Abbreviation c [%] Physical properties 1 CC-3-V 40.5 T(N, I) [ C.] = 74.0 2 CCY-3-O1 5.0 n (20 C., 589.3 nm) = 0.101 3 CCY-3-O2 11.0 (20 C., 1 kHz) = 3.6 4 CCY-4-O2 6.0 LTS (20 C.) [d] 15 5 CPY-2-O2 5.5 6 CPY-3-O2 11.0 7 CY-3-O2 5.0 8 PY-3-O2 12.0 9 B-3-O2 4.0 100

TABLE-US-00019 Mixture N-12: Composition Compound No. Abbreviation c [%] Physical properties 1 CY-3-O2 12.5 T(N, I) [ C.] = 110.5 2 CCY-3-O1 9.0 n (20 C., 589.3 nm) = 0.132 3 CCY-3-O2 11.0 (20 C., 1 kHz) = 4.9 4 CCY-4-O2 7.0 LTS (20 C.) [d] >76 5 CPY-3-O2 3.0 6 CC-3-V 31.0 7 B-2O-O5 4.0 8 PY-V2-O2 5.5 9 CPY-V-O2 6.0 10 CPY-V-O4 5.0 11 CCY-V-O2 6.0 100

TABLE-US-00020 Mixture N-13: Composition Compound No. Abbreviation c [%] Physical properties 1 CCGU-3-F 6.0 T(N, I) [ C.] = 109.5 2 CCQU-3-F 12.0 n (20 C., 589.3 nm) = 0.0986 3 CCQU-5-F 10.0 (20 C., 1 kHz) = +9.0 4 CCU-3-F 10.0 LTS (20 C.) [d] >42 5 CGPC-3-3 6.0 6 CP-3-O1 10.0 7 CCZU-3-F 15.0 8 CCZU-5-F 1.5 9 PGUQU-3-F 2.5 10 CPGU-3-OT 4.0 11 CPG-3-F 4.0 12 CPP-3-2 5.0 13 CC-3-4 4.0 14 CC-3-5 5.0 15 CC-3-O1 5.0 100

TABLE-US-00021 Mixture N-14: Composition Compound No. Abbreviation c [%] Physical properties 1 CPU-3-F 11.0 T(N, I) [ C.] = 124.0 2 CPU-5-F 11.0 n (20 C., 589.3 nm) = 0.1695 3 CGU-2-F 7.0 (20 C., 1 kHz) = +12.4 4 CGU-3-F 8.0 LTS (20 C.) [d] n/a 5 PGU-2-F 9.0 6 PGU-3-F 9.0 7 PGU-5-F 7.0 8 CCGU-3-F 8.0 9 CCP-V-1 6.0 10 CPPC-3-3 3.0 11 CGPC-3-3 5.0 12 CGPC-5-3 5.0 13 CGPC-5-5 5.0 14 PGIGI-3-F 6.0 100

TABLE-US-00022 Mixture N-15: Composition Compound No. Abbreviation c [%] Physical properties 1 CC-3-O1 8.0 T(N, I) [ C.] = 108.5 2 CCP-3-1 4.0 n (20 C., 589.3 nm) = 0.1082 3 CCP-3-3 7.0 (20 C., 1 kHz) = +13.4 4 CP-3-O1 8.0 LTS (20 C.) [d] >42 5 CCP-3-OT 9.0 6 CCP-5-OT 5.0 7 CPU-3-F 10.0 8 CCQU-3-F 20.0 9 CCGU-3-F 2.5 10 PUQU-3-F 3.0 11 APUQU-2-F 5.0 12 APUQU-3-F 8.0 13 PGUQU-3-F 5.0 14 CPGU-3-OT 3.5 15 CPGP-4-3 2.0 100

TABLE-US-00023 Mixture N-16: Composition Compound No. Abbreviation c [%] Physical properties 1 CC-3-V1 10.0 T(N, I) [ C.] = 114.3 2 PGUQU-3-F 4.0 n (20 C., 589.3 nm) = 0.0861 3 CCGU-3-F 5.5 (20 C., 1 kHz) = +11.2 4 CCG-3-OT 9.0 LTS (20 C.) [d] >28 5 CPU-3-F 11.0 6 CPU-5-F 4.0 7 CCQU-3-F 10.0 8 CCQU-5-F 7.5 9 CCZU-2-F 4.0 10 CCZU-3-F 12.0 11 CCZU-5-F 4.0 12 CCEG-3-F 12.0 13 CCEG-5-F 7.0 100

TABLE-US-00024 Mixture N-17: Composition Compound No. Abbreviation c [%] Physical properties 1 CPG-3-F 5.0 T(N, I) [ C.] = 114.5 2 CPG-5-F 5.0 n (20 C., 589.3 nm) = 0.1342 3 CPU-3-F 15.0 (20 C., 1 kHz) = 11.3 4 CPU-5-F 15.0 LTS (20 C.) [d] >1049 5 CP-3-N 16.0 6 CP-5-N 16.0 7 CCGU-3-F 7.0 8 CGPC-3-3 4.0 9 CGPC-5-3 4.0 10 CGPC-5-5 4.0 11 CCZPC-3-3 3.0 12 CCZPC-3-4 3.0 13 CCZPC-3-5 3.0 100

TABLE-US-00025 Mixture N-18: Composition Compound No. Abbreviation c [%] Physical properties 1 PZG-2-N 0.936 T(N, I) [ C.] = 108.5 2 PZG-3-N 0.936 n (20 C., 589.3 nm) = 0.1082 3 PZG-4-N 2.184 (20 C., 1 kHz) = +13.4 4 PZG-5-N 2.184 LTS (20 C.) [d] n/a 5 CP-3-O1 7.488 6 CC-3-4 3.120 7 CPP-3-2 2.496 8 CCZGI-3-3 2.496 9 CCZGI-3-5 2.496 10 CCZPC-3-3 1.248 11 CCZPC-3-4 1.248 12 CCZPC-3-5 0.936 13 CPZG-3-N 1.248 14 CGPC-5-3 1.248 15 CPPC-5-3 0.936 16 CPU-3-F 34.400 17 CPU-5-F 34.400 100

TABLE-US-00026 Mixture N-19: Composition Compound No. Abbreviation c [%] Physical properties 1 CP-5-3 20.0 T(N, I) [ C.] = n/a 2 CC-3-5 10.0 n (20 C., 589.3 nm) = 0.0730 3 CCU-2-F 12.0 (20 C., 1 kHz) = n/a 4 CCU-3-F 10.0 LTS (20 C.) [d] n/a 5 CCU-5-F 8.0 6 CCEG-3-F 10.0 7 CCEG-5-F 10.0 8 CCG-3-OT 10.0 9 CCG-5-OT 10.0 100

Device Examples

[0423] For the following device examples, the nematic host mixture N-17 is used and mixtures with the following dyes are prepared:

##STR00412## ##STR00413##

Comparative Example 1

[0424] The following comparative mixture C-1 which is known from the state of the art is prepared and investigated.

TABLE-US-00027 concentration Component c [%] N-17 99.077 Dye-1 0.279 Dye-2 0.049 Dye-3 0.195 Dye-4 0.400

TABLE-US-00028 TABLE 1 Properties of mixture C-1 in a device. Light Light transmittance transmittance (off-state) (on-state) .sub.v .sub.v .sub.v (on) .sub.v (off) single 46.2 79.9 33.7 cell.sup.[1] double 10.0 63.9 53.9 cell.sup.[1] Solar direct Solar direct transmittance transmittance (off-state) (on-state) .sub.e .sub.e .sub.e (on) .sub.e (off) single 66.5 84.3 17.8 cell.sup.[1] double 47.1 76.0 28.9 cell.sup.[1] .sup.[1]layer thickness = 25 m each Chromaticity coordinate of double cell in the off-state: X = 0.3129, y = 0.3290

[0425] The values shown in table 1 as well as the corresponding values below are measured according to norm EN410.

Example 1

[0426] A mixture M-1 containing 99.9% of nematic host mixture N-17 and 0.1% of BTD-1 is prepared and investigated.

[0427] The mixture M-1 shows two absorption maxima at 393 nm and 822 nm. At a wavelength of 822 nm the mixture M-1 shows a degree of anisotropy of 0.69. At 393 nm the degree of anisotropy is 0.65. This means, that both absorption bands have the same direction of polarisation. The extinction coefficients are shown in table 2.

TABLE-US-00029 TABLE 2 Extinction coefficients of mixture M-1 in a device. Wavelength 1/[% * cm] 822 nm _parallel 814 822 nm _perpendicular 114 393 nm _parallel 1466 393 nm _perpendicular 230

Example 2

[0428] A mixture M-2 is prepared as follows:

TABLE-US-00030 concentration Component c [%] N-17 99.35 BTD-1 0.17 BTD-2 0.17 BTD-3 0.17 BTD-7 0.14

TABLE-US-00031 TABLE 3 Properties of mixture M-2 in a device. Light Light transmittance transmittance (off-state) (on-state) .sub.v .sub.v .sub.v (on) .sub.v (off) single 93.0 95.7 2.7 cell.sup.[1] double 86.6 91.6 5.0 cell.sup.[1] Solar direct Solar direct transmittance transmittance (off-state) (on-state) .sub.e .sub.e .sub.e (on) .sub.e (off) single 73.5 84.6 11.1 cell.sup.[1] double 59.7 77.0 17.3 cell.sup.[1] .sup.[1]layer thickness = 25 m each

[0429] From table 3 can be seen that the mixture is switchable, as shown by the differences of transmittance values for the on and off states. Surprisingly, the switching in the NIR region of the electromagnetic spectrum is much higher than in the visible region which can be seen from the bigger difference between on and off state of the solar direct transmittance than of the corresponding values of the light transmittance.

[0430] The mixture M-2 is very well suitable for the use in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.

Example 3

[0431] A mixture M-3 is prepared as follows:

TABLE-US-00032 concentration Coponent c [%] N-17 99.077 Dye-1 0.218 Dye-2 0.028 Dye-3 0.328 BTD-1 0.170 BTD-2 0.170 BTD-3 0.170 BTD-7 0.091

TABLE-US-00033 TABLE 4 Properties of mixture M-3 in a device. Light Light transmittance transmittance (off-state) (on-state) .sub.v .sub.v .sub.v (on) .sub.v (off) single 44.7 76.5 31.8 cell.sup.[1] double 10.0 58.6 48.6 cell.sup.[1] Solar direct Solar direct transmittance transmittance (off-state) (on-state) .sub.e .sub.e .sub.e (on) .sub.e (off) single 58.5 78.4 19.9 cell.sup.[1] double 36.2 66.5 30.3 cell.sup.[1] .sup.[1]layer thickness = 25 m each Chromaticity coordinate of double cell in the off-state: X = 0.3131, y = 0.3293

[0432] As can be seen from the transmittance data in table 4, the mixture M-3 is very well switchable. The mixture M-3 is very well suitable for the use in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.

[0433] The comparison of the mixture M-3 with the comparative example C-1 from the state of the art shows that surprisingly, M-3 has an advantageously higher difference between on-state and off-state for the solar direct transmittance.

Example 4

[0434] A mixture M-4 is prepared as follows:

TABLE-US-00034 concentration Component c [%] N-17 98.803 Dye-1 0.187 Dye-2 0.069 Dye-3 0.241 Dye-4 0.130 Dye-5 0.130 Dye-6 0.130 Dye-7 0.110 Dye-8 0.200

TABLE-US-00035 TABLE 5 Properties of mixture M-4 in a device Light Light transmittance transmittance (off-state) (on-state) .sub.v .sub.v .sub.v (on) .sub.v (off) single 45.3 77.8 32.5 cell.sup.[1] double 10.0 60.5 50.5 cell.sup.[1] Solar direct Solar direct transmittance transmittance (off-state) (on-state) .sub.e .sub.e .sub.e (on) .sub.e (off) single 58.3 78.9 20.6 cell.sup.[1] double 35.6 67.1 31.5 cell.sup.[1] .sup.[1]layer thickness = 25 m each Chromaticity coordinate of double cell in the off-state: X = 0.3126, y = 0.3290

[0435] As can be seen from the transmittance data in table 5, the mixture M-4 is very well switchable. The mixture M-4 is very well suitable for the use in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.

[0436] The comparison of the mixture M-4 with the comparative example C-1 from the state of the art shows that surprisingly, M-4 has an advantageously higher difference between on-state and off-state for the solar direct transmittance.

Mixture Examples

[0437] To the host mixtures given above, the dyes according to the invention are added in the concentration given in the table below.

TABLE-US-00036 Mixture Host concentration example Mixture Dye of dye [%] .sub.max [nm] R M-1 N-17 BTD-1 0.1 822 0.69 M-2 N-1 BTD-1 0.1 N/A N/A M-3 N-2 BTD-1 0.1 N/A N/A M-4 N-3 BTD-1 0.1 N/A N/A M-5 N-4 BTD-1 0.1 N/A N/A M-6 N-5 BTD-1 0.1 N/A N/A M-7 N-6 BTD-1 0.1 N/A N/A M-8 N-7 BTD-1 0.1 N/A N/A M-9 N-8 BTD-1 0.1 N/A N/A M-10 N-9 BTD-1 0.1 N/A N/A M-11 N-10 BTD-1 0.1 N/A N/A M-12 N-11 BTD-1 0.1 N/A N/A M-13 N-12 BTD-1 0.1 N/A N/A M-14 N-13 BTD-1 0.1 N/A N/A M-15 N-14 BTD-1 0.1 N/A N/A M-16 N-15 BTD-1 0.1 N/A N/A M-17 N-16 BTD-1 0.1 N/A N/A M-18 N-18 BTD-1 0.1 N/A N/A M-19 N-19 BTD-1 0.1 N/A N/A

[0438] The mixtures M-1 to M-19 are very well suitable for the use in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.