DYE COMPOUNDS

Abstract

The present application relates to mixtures comprising at least one dye compound having a diketopyrrolopyrrole structure and at least one further liquid-crystalline compound. The application furthermore relates to the use of the mixtures in devices for regulating the entry of light into a space.

Claims

1. Mixture comprising at least one compound of the formula (I) ##STR00029## where the following applies to the symbols occurring: Y is on each occurrence, identically or differently, O or NR.sup.Y; Z.sup.1 is on each occurrence, identically or differently, a single bond or a group selected from CR.sup.3CR.sup.3 and CC, or two, three, four or five groups selected from the said groups combined with one another; Z.sup.2 is on each occurrence, identically or differently, a single bond or a group selected from O, S, C(R.sup.3).sub.2, C(R.sup.3).sub.2O, OC(R.sup.3).sub.2, CR.sup.3CR.sup.3 and CC, or two, three, four or five groups selected from the said groups combined with one another; Ar.sup.1 is on each occurrence, identically or differently, an aryl or heteroaryl group having 5 to 30 aromatic ring atoms, which may be substituted by one or more radicals R.sup.4; R.sup.Y, R.sup.1, R.sup.2, R.sup.3, R.sup.4 are on each occurrence, identically or differently, H, D, F, Cl, CN, N(R.sup.5).sub.2, an alkyl, alkoxy or thioalkoxy group having 1 to 15 C atoms or an alkenyl or alkynyl group having 2 to 15 C atoms, where the above-mentioned groups may each be substituted by one or more radicals R.sup.5 and where one or more CH.sub.2 groups in the above-mentioned groups may be replaced by R.sup.5CCR.sup.5, CC, CO, CS, C(O)O, O(CO), Si(R.sup.5).sub.2, NR.sup.5, O or S, or an aryl or heteroaryl group having 5 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.5; R.sup.5 is on each occurrence, identically or differently, H, D, F, Cl, CN, N(R.sup.6).sub.2, an alkyl, alkoxy or thioalkoxy group having 1 to 15 C atoms or an alkenyl or alkynyl group having 2 to 15 C atoms, where the above-mentioned groups may each be substituted by one or more radicals R.sup.6 and where one or more CH.sub.2 groups in the above-mentioned groups may be replaced by R.sup.6CCR.sup.6, CC, CO, CS, C(O)O, O(CO), Si(R.sup.6).sub.2, NR.sup.6, O or S, or an aryl or heteroaryl group having 5 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R.sup.6; R.sup.6 is on each occurrence, identically or differently, H, F or an aliphatic organic radical having 1 to 20 C atoms, in which one or more H atoms may be replaced by F, or an aryl or heteroaryl group having 5 to 20 C atoms, in which one or more H atoms may be replaced by F; i is on each occurrence, identically or differently, 0, 1, 2, 3 or 4; and at least one further compound selected from liquid-crystalline compounds.

2. Mixture according to claim 1, characterised in that Y in formula (I) is equal to O.

3. Mixture according to claim 1, characterised in that Z.sup.1 in formula (I) is a single bond.

4. Mixture according to claim 1, characterised in that Z.sup.2 in formula (I) is on each occurrence, identically or differently, a single bond or a group selected from CH.sub.2CH.sub.2, CF.sub.2CF.sub.2, OCH.sub.2, OCF.sub.2, CH.sub.2O, CF.sub.2O, CHCH, CFCF and CC.

5. Mixture according to claim 1, characterised in that Ar.sup.1 in formula (I) is on each occurrence, identically or differently, an aryl group having 6 to 13 aromatic ring atoms, which may be substituted by one or more radicals R.sup.4, or a heteroaryl group having 5 to 13 aromatic ring atoms, which may be substituted by one or more radicals R.sup.4.

6. Mixture according to claim 1, characterised in that Ar.sup.1 in formula (I) is selected on each occurrence, identically or differently, from benzene, fluorene, naphthalene, pyridine, pyrimidine, pyrazine, triazine, thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, indole, carbazole, thiazole, benzothiazole and quinoline, each of which may be substituted by one or more radicals R.sup.4.

7. Mixture according to claim 1, characterised in that R.sup.1 in formula (I) is on each occurrence, identically or differently, F or a straight-chain alkyl or alkoxy group having 3 to 12 C atoms, which may be substituted by one or more radicals R.sup.5, or a branched alkyl or alkoxy group having 3 to 12 C atoms, which may be substituted by one or more radicals R.sup.5, or a cyclic alkyl group having 6 C atoms, which may be substituted by one or more radicals R.sup.5, where one or more CH.sub.2 groups in the alkyl and alkoxy groups may be replaced by O or S.

8. Mixture according to claim 1, characterised in that R.sup.2 in formula (I) is on each occurrence, identically or differently, an alkyl group having 1 to 12 C atoms, which may be substituted by one or more radicals R.sup.5.

9. Mixture according to claim 1, characterised in that i in formula (I) is on each occurrence, identically or differently, 1 or 2.

10. Mixture according to claim 1, characterised in that the degree of anisotropy R of the compound of the formula (I) is greater than 0.6.

11. Mixture according to claim 1, characterised in that it comprises precisely one, two, three or four different compounds of the formula (I).

12. Mixture according to claim 1, characterised in that it comprises 3 to 25 different liquid-crystalline compounds.

13. Mixture according to claim 1, characterised in that it is a thermotropic liquid-crystalline material.

14. Mixture according to claim 1, characterised in that the at least one further compound selected from liquid-crystalline compounds contains two, three or four structural elements based on 1,4-phenylenes and 1,4-cyclohexylenes.

15. Mixture according to claim 1, characterised in that, in addition to the at least one compound of the formula (I) and the at least one compound selected from liquid-crystalline compounds, it comprises one or more dye compounds having a different structure than formula (I).

16. Mixture according to claim 15, characterised in that the dye compounds having a different structure than formula (I) are selected from perylenes, terrylenes, benzothiadiazoles and azo dyes.

17. A method for regulating the entry of light from one space into another space comprising passing said light through a device containing a switching layer wherein said switching layer contains a mixture according to claim 1.

18. Device for regulating the entry of light into a space, comprising a mixture according to claim 1.

19. The device according to claim 18, wherein said device comprises the following layer sequence, where further layers may additionally be present: substrate layer electrically conductive transparent layer alignment layer switching layer comprising said mixture, alignment layer electrically conductive transparent layer, and substrate layer.

20. Window containing a device according to claim 18.

Description

WORKING EXAMPLES

[0133] A) Syntheses of compounds of the formula (I)

[0134] A-1) Compound F1:

[0135] Compound F1 is prepared as shown in the following scheme:

##STR00010##

[0136] The first three synthesis steps here are carried out as indicated in S. P. Mishra et al, Synthetic Metals, 2010, 2422-2429.

[0137] For the final synthesis step, 2.0 g (2.93 mmol) of the diketopyrrolopyrrole precursor and 1.29 g (6.15 mmol) of the boronic acid and 2.84 g of Na.sub.2CO.sub.3 are dissolved in a toluene/water mixture. The solution is flushed with Ar and then heated to 50 C. 26.8 mg (0.03 mmol) of Pd.sub.2(dba).sub.3 and 35.7 mg (0.12 mmol) of tris(ortho-tolyl)phosphine are then added in one portion, and the solution is heated to 90 C. under reflux. After a reaction time of one hour, the mixture is worked up by filtration through Celite 545. The solution is washed with water. After removal of the solvent, the crude product is obtained as a dark-green solid. This is recrystallised from toluene, giving the product in a purity of 99.9% (HPLC) and in a yield of 69%.

[0138] A-2) The following compounds are prepared analogously from the starting material

##STR00011##

by reaction with the alternative boronic acid derivatives indicated below:

TABLE-US-00001 Name Starting material Yield Purity F2 [00012] 43% 99.7% (HPLC) F3 [00013] 51% 98.1% (HPLC) F3B [00014] not det. not det.

[0139] A-3) Compound F3C is prepared analogously to the synthesis of F1 (cf. S. P. Mishra et al, Synthetic Metals, 2010, 2422-2429) by the following synthesis route:

##STR00015##

[0140] A-4) Compound F3A is prepared by an analogous synthesis route using

##STR00016##

as nitrile component and dimethyl sulfate as alkylating agent in the final step:

##STR00017##

[0141] A-5) The following compound F3D, for example, is commercially available (Aldrich) as a further compound of the formula (I):

##STR00018##

[0142] B) Mixtures comprising compounds of the formula (I) and their properties

[0143] B-1) A solution of each of compounds F1, F2, F3, F3A and F3B in accordance with the invention and a compound F4 as comparison (structures see Table 1) in host mixture H1 (composition see Table 2) was prepared.

TABLE-US-00002 TABLE 1 [00019] F1 [00020] F2 [00021] F3 [00022] F3A [00023] F3B [00024] F4

TABLE-US-00003 TABLE 2 H1 Composition Compound % CPG-3-F 5 CPG-5-F 5 CPU-3-F 15 CPU-5-F 15 CP-3-N 16 CP-5-N 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

[0144] The mixtures with dye F1, F2, F3, F3A, F3B or F4 are each characterised with respect to their absorption maximum, their degree of anisotropy of the absorption R, their fluorescence intensity, their light stability and the stability of the solution at high and low temperature.

[0145] For the determination of R, a method familiar to the person skilled in the art is used. It is disclosed in detail in WO 2014/090367. For better comparability, the fluorescence intensity (arbitrary units) is determined at a concentration c* of the dye at which a TN cell containing the mixture with a cell thickness of 25 pm has a dark state with 35% transmission. The light stability (fading) is determined by continuous exposure. The stability of the solution is determined by storing a solution of the dye in the concentration indicated until spectroscopically detectable precipitation occurs.

TABLE-US-00004 TABLE 3 Iso- Sol. Sol. tropic stability stability ext. Aniso- Fluores- +20 C. 20 C. Dye in Absorp. coeff. tropy cence at Fading (weeks (weeks mixture max./nm .sub.iso R c* (a.u.) (weeks) at conc.) at conc.) F1 in H1 617 810 0.78 2485 >29 12 at 12 at (98%) 2.6% 1.5% F2 in H1 623 877 0.78 2802 17 not det. not det. (80%) F3 in H1 624 770 0.74 2983 10 12 at 12 at (80%) 1.4% 0.8% F3A in 506 628 0.41 not det. not det. not det. not det. H1 F3B in 620 870 0.79 not det. not det. not det. not det. H1 F4 in H1 657 832 0.76 2360 26 8 at 8 at (comp.) (98%) 0.4% 1.3%

[0146] B-2) Further mixtures according to the invention were prepared. These each comprise one of the dyes F1, F2 and F3 in liquid-crystalline mixture H2 or H3 (composition see Table 4).

TABLE-US-00005 TABLE 4 H2 H3 Composition CY-3-O2 12 CCN-33 10 CY-5-O2 12 CCN-47 10 CCY-3-O2 13 CCN-57 10 CCY-5-O2 13 CY-3-O2 5 CCY-3-1 8 NCB-53 13 CCZC-3-3 4 CCY-3-O2 5 CCZC-3-5 3 CCY-3-O3 5 CCZC-4-3 3 CCY-4-O2 6 CC-3-4 6 CPY-2-O2 9 CC-3-5 6 CPY-3-O2 8 CC-3-O3 8 PYP-2-3 7 CC-5-O1 4 PYP-2-4 6 CC-5-O2 4 CGPC-3-3 2 CP-3-O2 4 CGPC-5-3 2 CGPC-5-5 2

[0147] The following results are obtained for the solubility stability (the data in % here denote % by weight):

TABLE-US-00006 TABLE 5 Dye in Sol. stability Sol. stability mixture +20 C. (weeks at conc.) 20 C. (weeks at conc.) F1 in H2 12 at 12 at 1.2% 1.4% F3 in H2 12 at 12 at 0.8% 0.9% F1 in H3 12 at 12 at 2.2% 1.7% F3 in H3 12 at 12 at 1.3% 0.8%

[0148] The mixtures comprising dye F1, F2 or F3 are distinguished by very strong fluorescence. Furthermore, they have a high degree of anisotropy and high light and solution stability. This is shown for the three liquid-crystalline mixtures H1, H2 and H3.

[0149] Owing to these properties, the compounds are highly suitable for use as liquid-crystalline media in displays or in devices for regulating the entry of light into a space (smart windows).

[0150] B-3) As a further investigation method, compounds F1, F3 and F4 were dissolved in liquid-crystalline mixtures H1, H2 and H4 (composition see below). The mixtures obtained were investigated by a new method (spectroscopic investigation of the solubility in supersaturated solutions). The following results were obtained (the data in % here denote % by weight):

TABLE-US-00007 F4 (comp.) F1 F3 +20 C. 20 C. +20 C. 20 C. +20 C. 20 C. H1 0.74% 1.37% 2.75% 1.98% 2.04% 1.22% H2 0.11% 0.28% 1.55% 2.14% 1.07% 1.87% H4 0.06% 0.04% 1.45% 1.64% not det. not det.

TABLE-US-00008 H4 Composition CY-3-O2 9 CY-3-O4 9 CY-5-O2 12 CY-5-O4 8 CCY-3-O2 5 CCY-3-O3 5 CCY-4-O2 5 CPY-2-O2 7 CPY-3-O2 6 PYP-2-3 12 CCP-V-1 6 CCZPC-3-3 3 CCZPC-3-4 3 CGPC-3-3 5 CGPC-5-3 5

[0151] The results clearly show the advantages of the mixtures according to the invention comprising material F1 or F3 compared with mixtures comprising comparative material F4. In the above table, the lowest value determined for the solubility at 20 C. or at -20 C. in each case denotes the highest concentration that can be employed technically.

[0152] In detail, the above results illustrate that F1 and F3 can be employed in significantly higher concentrations in H1 and H2 than F4. In mixture H4, F4 cannot be employed at all, since it has only negligible solubility. By contrast, F1 is soluble in mixture H4 and can thus be employed.

[0153] C) Production of devices according to the invention (smart windows)

[0154] Dyes F1, F4, F5 and F6 shown in Table 6 below are dissolved in liquid-crystalline mixture H1 (see above) in the amounts indicated therein.

TABLE-US-00009 TABLE 6 [00025] F1: 0.152% by weight [00026] F4: 0.118% by weight [00027] F5: 0.138% by weight [00028] F6: 0.277% by weight

[0155] The mixture comprising the four dyes F1, F4, F5 and F6 is introduced into a single host/guest cell, as described in WO 2014/090373. The cell has a thickness of 23.6 m. The cell is switched from bright to dark, and the light transmissivity .sub.v, calculated in accordance with European Standard EN410, equation (1), is determined for both states. The colour location of the device is also determined in CIE x,y coordinates.

[0156] Furthermore, the mixture comprising the four dyes F1, F4, F5 and F6 is introduced into a host/guest double cell, as described in the as yet unpublished application EP13002445.8. The cell has a thickness of 23.6 m. The same parameters are determined as for the single host/guest cell.

[0157] The results of the measurements are summarised in Table 7 below.

TABLE-US-00010 TABLE 7 State CIE x CIE y .sub.v Single cell dark 0.311 0.333 51.8% bright 0.313 0.331 84.3% Double cell dark 0.306 0.345 16.3% bright 0.312 0.332 71.1%

[0158] The results show that the dye mixture according to the invention enables the production of devices for regulating the entry of light into a space which have a high range of light transmission on switching from bright to dark, combined with a virtually ideal colour location (black/white).