AZO DYE

Abstract

The present invention relates to azo dye of formula I

##STR00001##

defined in claim 1, to a liquid crystalline medium comprising said azo dye, the use of said medium for optical, electrooptical 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. The invention further relates to a device containing the liquid crystalline medium according to the invention.

Claims

1. Compound of formula I ##STR00417## in which W.sup.11, W.sup.12 identically or differently, denote O, S or Se, ##STR00418##  on each occurrence, identically or differently, denotes ##STR00419## 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)—, —C≡C—, —N(R.sup.z)—, —O—, —S—, —CO—, —CO—O—, —O—CO— or —O—CO—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—, —CO—, —CO—O—, —O—CO— or —O—CO—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, 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 —CH═CH—, Z.sup.10, Z.sup.11, Z.sup.12 on each occurrence, identically or differently, denote a single bond, —N═N—, —CH═N—, —N═CH—, —N═N(O)—, —N(O)═N—, —CR.sup.x1═CR.sup.x2—, —(CR.sup.x1═CR.sup.x2).sub.2—, —C≡C—, —C(═O)—, —CH═CH—C(═O)—, —C(═O)—CH═CH—, —CH═CH—COO— or —OCO—CH═CH—, Z.sup.21, Z.sup.22 on each occurrence, identically or differently, have one of the meanings of Z.sup.10 or denote —O—, —S—, —CR.sup.y1R.sup.y2—, —CF.sub.2O—, —OCF.sub.2—, —C(O)—O—, —O—C(O)—, —O—C(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—, or —(CF.sub.2).sub.n1—, 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.sup.x11, R.sup.x12, R.sup.x13, R.sup.x14 independently of one another, denote H, F, Cl, CN, alkyl, alkenyl, alkoxy or alkenyloxy having 1-12 C atoms, r and t, independently of one another, denote 0, 1 or 2, s 0 or 1, and n1 denotes 1, 2, 3 or 4, and wherein one or more of Z.sup.10, Z.sup.11, Z.sup.12, Z.sup.21, Z.sup.22, denote —N═N—.

2. Compound according to claim 1, wherein W.sup.11 and W.sup.12 denote S.

3. Compound according to claim 1, wherein the compound is selected from the group of compounds of the following sub-formulae, ##STR00420## 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 and Z.sup.22 have the meanings defined in claim 1.

4. Compound according to claim 1, wherein A.sup.11 and A.sup.12, identically or differently, denote 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 are optionally replaced by a group L as defined in claim 1.

5. Compound according to claim 1, wherein ##STR00421## denotes ##STR00422## in which R.sup.x11, R.sup.x12, R.sup.x13, R.sup.x14 independently of one another, denote H, F, Cl, CN, alkyl, alkenyl, alkoxy or alkenyloxy each having 1-12 C atoms.

6. Compound according to claim 1, wherein Z.sup.11, Z.sup.12, Z.sup.22, identically or differently, denote a single bond, —CR.sup.x1═CR.sup.x2— or —C≡C—, in which R.sup.x1 and R.sup.x2 have the meanings given in claim 1.

7. Compound according to claim 1, wherein 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.

8. LC medium, characterised in that the medium comprises a dye component A) comprising one or more compounds of the formula I according to claim 1 and optionally further dichroic dyes, and a liquid-crystalline component B), also referred to as “LC host mixture”, comprising one or more mesogenic compounds.

9. LC medium according to claim 8, wherein the medium comprises an LC host mixture with negative dielectric anisotropy comprising one or more compounds selected from the group of compounds of the formulae CY, PY and AC ##STR00423## in which ##STR00424##  denotes ##STR00425##  denote ##STR00426##  denotes ##STR00427## 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—, —CH═CH—, —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—, —CH═CH—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CO—O—, —O—CO—, —C.sub.2F.sub.4—, —CF═CF—, —CH═CH—CH.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.

10. LC medium according to claim 8, wherein the medium comprises an LC host mixture with positive dielectric anisotropy comprising one or more compounds selected from the group of compounds of formulae II to VIII ##STR00428## in which ##STR00429##  each, independently of one another, denote ##STR00430## 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 —C≡C—, —CF.sub.2O—, —CH═CH—, ##STR00431## —O—, —CO—O— or —O—CO— in such a way that O 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—, —CH═CH—, —CF═CF—, —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.

11. LC medium according to claim 8, wherein the medium comprises one or more compounds selected from the group of compounds of formulae DK and O ##STR00432## in which 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—, —CH═CH—, —CO—, —OCO— or —COO— in such a way that O atoms are not linked directly to one another, ##STR00433##  denotes ##STR00434##  denotes ##STR00435##  denotes ##STR00436##  denotes ##STR00437## Z.sup.O1 denotes —CH.sub.2CH.sub.2—, —CF.sub.2CF.sub.2—, —C═C— 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.

12. LC medium according to claim 11, 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 ##STR00438## in which 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.

13. LC medium according to claim 11, 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: ##STR00439## ##STR00440## 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.

14. A device or composition selected from 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 dyes for colouring polymers, which comprises a compound according to claim 1.

15. Device for regulating the passage of energy from an outside space into an inside space, wherein the device contains a switching layer comprising an LC medium according to claim 8.

16. Window containing a device according to claim 15.

Description

EXAMPLES

[0387] The present invention is described in detail by the following, non-restrictive examples.

[0388] 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 Δn is determined at 589 nm, and the value of Δε 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.

[0389] 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.

[0390] 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.

[0391] 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 Crystals—Applications and Uses, Vol. 3, 1992, World Scientific Publishing, Section 11.4.2.

Synthesis Examples

Example 1 [Azo-1]

[0392] ##STR00407##

[0393] 4,7-Bis-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)benzo[1,2,5]thiadiazole (50.0 mg) and (4-bromo-phenyl)-(4-propyl-phenyl)diazene (76.9 mg) water (3.20 ml; 0.178 mol), sodium (20.22 mg; 0.241 mmol) and THE (6 ml) are placed in a round bottom flask under argon and bis(tri-tert.-butylphosphin)palladium(0) (0.12 mg; 0.241 μmol) are added. The reaction is heated under reflux and stirred overnight at room temp. Aqeous work up and filtration of the crude product with toluene through silica yields (4-Propylphenyl)-[4-[4-[4-[(4-propylphenyl)azo]phenyl]-2,1,3-benzothiadiazol-7-yl]phenyl]diazene.

[0394] Phase sequence K 183 N 2901 (decomp.)

Example 2 [Azo-2]

[0395] ##STR00408##

[0396] In analogy to Example 1, from 4,7-bis-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-benzo[1,2,5]thiadiazole and (4-bromo-phenyl)-(2-fluoro-4-(3-ethylheptyl)-phenyl)-diazene, [4-(3-ethylheptyl)-2-fluoro-phenyl]-[4-[4-[4-[[4-(3-ethylheptyl)-2-fluoro-phenyl]azo]phenyl]-2,1,3-benzothiadiazol-7-yl]phenyl]diazene is obtained.

[0397] Phase sequence: K 102 SmA 164 N 208 I

Example 3 [Azo-3]

[0398] ##STR00409##

[0399] In analogy to Example 1, from 4,7-bis-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-benzo[1,2,5]thiadiazole and (4-bromophenyl)-[4-(2-ethylhexoxy)-1-naphthyl]diazene, [4-(2-ethylhexoxy)-1-naphthyl]-[4-[4-[4-[[4-(2-ethylhexoxy)-1-naphthyl]azo]phenyl]-2,1,3-benzothiadiazol-7-yl]phenyl]diazene is obtained. Phase sequence: K 188 N (168) I

Example 4 [Azo-4]

[0400] ##STR00410##

[0401] In analogy to Example 1, from 4,7-bis-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-benzo[1,2,5]thiadiazole and (4-bromophenyl)-[4-(2-ethylhexoxy)-1-phenyl]diazene, [4-(2-ethylhexoxy)-1-naphthyl]-[4-[4-[4-[[4-(2-ethylhexoxy)-1-phenyl]azo]phenyl]-2,1,3-benzothiadiazol-7-yl]phenyl]diazene is obtained.

[0402] Phase sequence: K 129 SmX 203 N 246 I

Example 5 [Azo-5]

[0403] ##STR00411##

[0404] In analogy to Example 1, from 4,7-bis-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-benzo[1,2,5]thiadiazole and 0.5 equivalents each of (4-bromophenyl)-[4-(2-ethylhexoxy)-1-naphthyl]diazene and 2-bromo-5-[4-(3-ethylheptyl)-2-fluoro-phenyl]thiophene, [4-[4-[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-2,1,3-benzothiadiazol-7-yl]phenyl]-[4-(2-ethylhexoxy)-1-naphthyl]diazene is obtained.

[0405] Phase sequence: Tg −5 K 92 N (85.2) I

Example 6 [Azo-6]

[0406] ##STR00412##

[0407] In analogy to Example 1, from 4,7-bis-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-benzo[1,2,5]thiadiazole and 0.5 equivalents each of (4-bromophenyl)-[4-(2-ethylhexoxy)-1-phenyl]diazene and 2-bromo-5-[4-(3-ethylheptyl)-2-fluoro-phenyl]thiophene, [4-[4-[5-[4-(3-ethylheptyl)-2-fluoro-phenyl]-2-thienyl]-2,1,3-benzothiadiazol-7-yl]phenyl]-[4-(2-ethylhexoxy)-1-phenyl]diazene is obtained.

[0408] Phase sequence: K 124 SmX (121) I

[0409] In analogy to the above described procedures, the following examples are obtained:

##STR00413##

Use Examples

[0410] 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 BTD-1 to BTD-3 and AD-1 to AD-3 known from the state of the are given.

##STR00414##

[0411] Optionally, a stabiliser ST-1 or ST-2 is added to the medium.

##STR00415## ##STR00416##

Preparation of Liquid-Crystalline Dye Mixtures

[0412] Nematic LC host mixtures N-1 to N-20 are prepared as follows:

TABLE-US-00008 Mixture N-1: Composition Compound No. Abbreviation c [%] 1 CY-3-O2 12.0 2 CY-5-O2 12.0 3 CCY-3-O2 13.0 4 CCY-5-O2 13.0 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 Σ 100 Physical properties T(N, I) [° C.] = 91.5 Δn (20° C., 589.3 nm) = 0.078 Δε (20° C., 1 kHz) = −3.7 LTS (−20° C.) [d] 27

TABLE-US-00009 Mixture N-2: Composition Compound No. Abbreviation c [%] 1 CY-3-O2 12.0 2 CY-5-O2 13.0 3 CCY-3-O2 11.0 4 CCY-5-O2 10.0 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 Σ 100 Physical properties T(N, I) [° C.] = 79.5 Δn (20° C., 589.3 nm) = 0.100 Δε (20° C., 1 kHz) = −3.1 LTS (−20° C.) [d] >42

TABLE-US-00010 Mixture N-3: Composition Compound No. Abbreviation c [%] 1 CC(CN)-4-7 20.0 2 CC(CN)-5-5 21.0 3 CC-3-O1 11.0 4 CC-5-O1 5.0 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 Σ 100 Physical properties T(N, I) [° C.] = 100.5 Δn (20° C., 589.3 nm) = 0.044 Δε (20° C., 1 kHz) = −4.8 LTS (−20° C.) [d] >42

TABLE-US-00011 Mixture N-4: Composition Compound No. Abbreviation c [%] 1 CC(CN)-3-3 10.0 2 CC(CN)-4-7 10.0 3 CC(CN)-5-7 10.0 4 CY-3-O2 5.0 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 Σ 100 Physical properties T(N, I) [° C.] = 106.0 Δn (20° C., 589.3 nm) = 0.118 Δε (20° C., 1 kHz) = −6.0 LTS (−20° C.) [d] >73

TABLE-US-00012 Mixture N-5: Composition Compound No. Abbreviation c [%] 1 CC(CN)-3-3 8.0 2 CC(CN)-4-7 8.0 3 CC(CN)-5-5 9.0 4 CY-3-O2 5.0 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 Σ 100 Physical properties T(N, I) [° C.] = 113.5 Δn (20° C., 589.3 nm) = 0.127 Δε (20° C., 1 kHz) = −6.0 LTS (−20° C.) [d] >100

TABLE-US-00013 Mixture N-6: Composition Compound No. Abbreviation c [%] 1 CC(CN)-3-3 13.0 2 CC(CN)-4-7 15.0 3 CC(CN)-5-5 12.0 4 PPC(CN)-5-3 10.0 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 Σ 100 Physical properties T(N, I) [° C.] = 107.5 Δn (20° C., 589.3 nm) = 0.103 Δε (20° C., 1 kHz) = −4.9 LTS (−20° C.) [d] >83

TABLE-US-00014 Mixture N-7: Composition Compound No. Abbreviation c [%] 1 CC(CN)-4-7 10.0 2 CC(CN)-5-5 10.0 3 CY-3-O2 6.0 4 CP-3-O1 10.0 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 Σ 100 Physical properties T(N, I) [° C.] = 111.5 Δn (20° C., 589.3 nm) = 0.124 Δε (20° C., 1 kHz) = −4.7 LTS (−20° C.) [d] >73

TABLE-US-00015 Mixture N-8: Composition Compound No. Abbreviation c [%] 1 CC(CN)-3-3 8.0 2 CC(CN)-4-7 10.0 3 CC(CN)-5-5 10.0 4 CY-3-O2 10.0 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 Σ 100 Physical properties T(N, I) [° C.] = 107.5 Δn (20° C., 589.3 nm) = 0.129 Δε (20° C., 1 kHz) −5.5 LTS (−20° C.) [d] >73

TABLE-US-00016 Mixture N-9: Composition Compound No. Abbreviation c [%] 1 CY-3-O2 9.0 2 CY-3-O4 9.0 3 CY-5-O2 12.0 4 CY-5-O4 8.0 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 Σ 100 Physical properties T(N, I) [° C.] = 110.5 Δn (20° C., 589.3 nm) = 0.132 Δε (20° C., 1 kHz) = −4.9 LTS (−20° C.) [d] >76

TABLE-US-00017 Mixture N-10: Composition Compound No. Abbreviation c [%] 1 CC-3-V 41.5 2 CCY-3-O1 5.0 3 CCY-3-O2 11.0 4 CCY-4-O2 6.0 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 Σ 100 Physical properties T(N, I) [° C.] = 74.0 Δn (20° C., 589.3 nm) = 0.101 Δε (20° C., 1 kHz) = −3.5 LTS (−20° C.) [d] 13

TABLE-US-00018 Mixture N-11: Composition Compound No. Abbreviation c [%] 1 CC-3-V 40.5 2 CCY-3-O1 5.0 3 CCY-3-O2 11.0 4 CCY-4-O2 6.0 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 Σ 100 Physical properties T(N, I) [° C.] = 74.0 Δn (20° C., 589.3 nm) = 0.101 Δε (20° C., 1 kHz) = −3.6 LTS (−20° C.) [d] 15

TABLE-US-00019 Mixture N-12: Composition Compound No. Abbreviation c [%] 1 CY-3-O2 12.5 2 CCY-3-O1 9.0 3 CCY-3-O2 11.0 4 CCY-4-O2 7.0 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 Σ 100 Physical properties T(N, I) [° C.] = 110.5 Δn (20° C., 589.3 nm) = 0.132 Δε (20° C., 1 kHz) = −4.9 LTS (−20° C.) [d] >76

TABLE-US-00020 Mixture N-13: Composition Compound No. Abbreviation c [%] 1 CCGU-3-F 6.0 2 CCQU-3-F 12.0 3 CCQU-5-F 10.0 4 CCU-3-F 10.0 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 Σ 100 Physical properties T(N, I) [° C.] = 109.5 Δn (20° C., 589.3 nm) = 0.0986 Δε (20° C., 1 kHz) = +9.0 LTS (−20° C.) [d] >42

TABLE-US-00021 Mixture N-14: Composition Compound No. Abbreviation c [%] 1 CPU-3-F 11.0 2 CPU-5-F 11.0 3 CGU-2-F 7.0 4 CGU-3-F 8.0 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 Σ 100 Physical properties T(N, I) [° C.] = 124.0 Δn (20° C., 589.3 nm) = 0.1695 Δε (20° C., 1 kHz) = +12.4 LTS (−20° C.) [d] n/a

TABLE-US-00022 Mixture N-15: Composition Compound No. Abbreviation c [%] 1 CC-3-O1 8.0 2 CCP-3-1 4.0 3 CCP-3-3 7.0 4 CP-3-O1 8.0 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 CPG P-4-3 2.0 Σ 100 Physical properties T(N, I) [° C.] = 108.5 Δn (20° C., 589.3 nm) = 0.1082 Δε (20° C., 1 kHz) = +13.4 LTS (−20° C.) [d] >42

TABLE-US-00023 Mixture N-16: Composition Compound No. Abbreviation c [%] 1 CC-3-V1 10.0 2 PGUQU-3-F 4.0 3 CCGU-3-F 5.5 4 CCG-3-OT 9.0 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 Σ 100 Physical properties T(N, I) [° C.] = 114.3 Δn (20° C., 589.3 nm) = 0.0861 Δε (20° C., 1 kHz) = +11.2 LTS (−20° C.) [d] >28

TABLE-US-00024 Mixture N-17: Composition Compound No. Abbreviation c [%] 1 CPG-3-F 5.0 2 CPG-5-F 5.0 3 CPU-3-F 15.0 4 CPU-5-F 15.0 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 Σ 100 Physical properties T(N, I) [° C.] = 114.5 Δn (20° C., 589.3 nm) = 0.1342 Δε (20° C., 1 kHz) = 11.3 LTS (−20° C.) [d] >1049

TABLE-US-00025 Mixture N-18: Composition Compound No. Abbreviation c [%] 1 PZG-2-N 0.936 2 PZG-3-N 0.936 3 PZG-4-N 2.184 4 PZG-5-N 2.184 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 Σ 100 Physical properties T(N, I) [° C.] = 108.5 Δn (20° C., 589.3 nm) = 0.1082 Δε (20° C., 1 kHz) = +13.4 LTS (−20° C.) [d] n/a

TABLE-US-00026 Mixture N-19: Composition Compound No. Abbreviation c [%] 1 CP-5-3 20.0 2 CC-3-5 10.0 3 CCU-2-F 12.0 4 CCU-3-F 10.0 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 Σ 100 Physical properties T(N, I) [° C.] = n/a Δn (20° C., 589.3 nm) = 0.0730 Δε (20° C., 1 kHz) = n/a LTS (−20° C.) [d] n/a

TABLE-US-00027 Mixture N-20 CPG-3-F 11.4% T.sub.(N, I). [° C.]: CPG-5-F 9.5% Δn (589.3 nm, 20° C.) CCEP-3-OT 4.75% n.sub.e (589.3 nm, 20° C.) CCEP-5-OT 4.75% n.sub.o (589.3 nm, 20° C.) CGPC-3-3 1.9% Δε (1 kHz, 20° C.): CGPC-5-3 1.9% ε.sub.∥ (1 kHz, 20° C.): CGPC-5-5 1.9% ε.sub.⊥ (1 kHz, 20° C.): CP-6-F 7.6% γ.sub.1 [mPa .Math. s], (20° C.): CP-7-F 5.7% K.sub.1 [pN], (20° C.): CCP-2-OT 7.6% K.sub.3 [pN], (20° C.): CCP-3-OT 11.4% V.sub.0 [V], (20° C.): CCP-4-OT 6.65% CCP-5-OT 10.45% CP-7-F 9.5% PM-5-N 5.0% Σ 100.0%

[0413] To the host mixtures given above, the dyes according to the invention are added in the concentration given in table 1 below.

TABLE-US-00028 TABLE 1 Mixture Host concentration example Mixture Dye of dye [%] M-1 N-1 Azo-1 0.20 M-2 N-2 Azo-1 0.25 M-3 N-3 Azo-1 0.30 M-4 N-4 Azo-1 0.35 M-5 N-5 Azo-1 0.15 M-6 N-6 Azo-1 0.20 M-7 N-7 Azo-1 0.24 M-8 N-8 Azo-1 0.23 M-9 N-9 Azo-1 0.27 M-10 N-10 Azo-1 0.35 M-11 N-11 Azo-1 0.20 M-12 N-12 Azo-1 0.20 M-13 N-13 Azo-1 0.25 M-14 N-14 Azo-1 0.25 M-15 N-15 Azo-1 0.30 M-16 N-16 Azo-1 0.30 M-17 N-17 Azo-1 0.32 M-18 N-18 Azo-1 0.25 M-19 N-19 Azo-1 0.25 M-20 N-17 Azo-2 0.25 M-21 N-17 Azo-3 0.25 M-22 N-17 Azo-4 0.25 M-23 N-17 Azo-5 0.25 M-24 N-17 Azo-6 0.25

[0414] For the mixtures M-25 to M-29 comprising the dyes Azo- to Azo-5, respectively, the maximum absorption wavelength (λ.sub.max), the extinction coefficient at the absorption maximum (ε (λ.sub.max)) and the degree of anisotropy (R) are determined as follows (table 2):

TABLE-US-00029 TABLE 2 Mixture Host Compound λ.sub.max [nm] ε (λ.sub.max) R M-25 N-20 Azo-1 417 776 0.79 M-26 N-20 Azo-2 420 542 0.80 M-27 N-20 Azo-3 442 635 0.71 M-28 N-20 Azo-4 424 655 0.78 M-29 N-20 Azo-5 475 470 0.72

[0415] For comparison, the following comparative Mixtures C-1 to C-4 are prepared (table 3).

TABLE-US-00030 TABLE 3 conc. of conc. of Mixture Host dyes Stabiliser λ.sub.max example Mixture Dyes [%] Stabiliser [%] [nm] R C-1 N-17 BTD-1 0.25 — — 534 0.70 C-2 N-17 BTD-2 0.25 — — 412 0.69 C-3 N-17 BTD-3 0.25 — — 505 0.76 C-4 N-9 AD-1 0.16 ST-1 0.08 AD-2 0.35 AD-3 0.43

[0416] In Table 3, the given concentration of the one or more dyes and optionally stabiliser and of the host mixture add up to a total concentration of 100%.

[0417] It can be seen, that the compounds Azo-1 to Azo-5 have similar absorption characteristics and R values as the compounds BTD-1 to BTD-3 and are equally well suitable for the applications according to the invention, especially in devices for regulating the passage of energy from an outside space into an inside space, preferably in windows.

[0418] The compounds according to the invention are distinguished by a surprisingly high solubility in liquid crystalline media and a high degree of anisotropy (R).

[0419] Fluorescence spectra are measured using an Ocean Optics USB-400 fluorescence spectrometer with a Monoscan 2000 monochromator and a UV/Vis/NIR DH-2000-BAL light source in a THE solution at a concentration of 10 mg/l.

[0420] Surprisingly, the dyes of formula I according to the invention show acceptably low fluorescence in the visible region of the electromagnetic spectrum compared to compounds of the state of the art. As the emission of light by fluorescence of the dyes is unwanted in applications for example in windows because of the resulting coloration, the dyes according to the invention are particularly suitable for window applications.

[0421] The following fluorescence values are observed (table 4):

TABLE-US-00031 TABLE 4 Dye λ.sub.max [nm] BTD-1 519 BTD-2 536 BTD-3 509 Azo-1 — Azo-2 — Azo-3 — Azo-4 — Azo-5 — Azo-6 —

[0422] The dyes BTD-1, BTD-2 and BTD-3 show strong emissions in the visible range with a peak emission at the respective wavelength given in table 4. Under the same conditions, for the compounds Azo-1 to Azo-6 no fluorescence is detectable.