Liquid crystals
AssigneeHoffmann-La Roche Inc.
InventorMartin Petrzilka
Life of this patent
Estimating the term…
Abstract
Compounds of the formula ##STR1## wherein, inter alia, R.sup.1 is hydrogen or straight-chain alkyl; R.sup.2 is --CN, --R, --COR, --COOR; R is alkyl; A is a group with 1 to 4 six-membered rings, these rings being linked directly with one another and with ring B in each case via a single covalent bond or being linked at one or two positions also via ester or ether groups; the six-membered rings in A and ring B each are 1,4-phenylene or trans-1,4-cyclohexylene or one of these rings also is trans-2,5-disubstituted m-dioxane; m can be 0 when ring B is trans-1,4-cyclohexylene or trans-2,5-disubstituted m-dioxane, liquid crystalline mixtures which contain these compounds as well as their use for electro-optical purposes are described.
Claims27
A compound of the formula:
- ##STR21## wherein R.sup.1 is hydrogen or straight-chain alkyl;
- R.sup.2 is --CN, --R, --COR, --COOR or when R.sup.2 is positioned on an aromatic ring R.sup.2 also can be --OR or --OOCR;
- R is alkyl;
- A is a group with 1 to 4 six-membered rings, these rings being linked directly with one another and with ring B in each case via a single covalent bond or being linked at one or two positions also via --COO--, --OOC-- or --CH.sub.2 --CH.sub.2 --;
- ring B is trans-1,4-cyclohexylene and the six-membered rings in A each are 1,4-phenylene or trans-1,4-cyclohexylene or one of these rings in A also is trans-2,5-disubstituted m-dioxane, 2,5-disubstituted pyrimidine or 3,6-disubstituted pyridazine;
- or ring B is trans-2,5-disubstituted m-dioxane and the six membered rings in A each are 1,4-phenylene or trans-1,4-cyclohexylene;
- with the proviso that a maximum of two adjacent trans-1,4-cyclohexylene rings are linked directly via a single covalent bond and with the further proviso that ring B or one of the rings in group A is a heterocyclic ring when ring B and group A are linked directly via a single covalent bond;
- and m is the integer 0 or 2.
A liquid crystalline mixture comprising at least two components, wherein at least one component is a compound of the formula:
- ##STR28## wherein R.sup.1 is hydrogen or straight-chain alkyl;
- R.sup.2 is --CN, --R, --COR, --COOR or when R.sup.2 is positioned on an aromatic ring R.sup.2 also can be --OR or --OOCR;
- R is alkyl;
- A is a group with 1 to 4 six-membered rings, these rings being linked directly with one another and with ring B in each case via a single covalent bond or being linked at one or two positions also via --COO--, --OOC-- or --CH.sub.2 --CH.sub.2 --;
- ring B is trans-1,4-cyclohexylene and the six-membered rings in A each are 1,4-phenylene or trans-1,4-cyclohexylene or one of these rings in A also is trans-2,5-disubstituted m-dioxane, 2,5-disubstituted pyrimidine or 3,6-disubstituted pyridazine;
- or ring B is trans-2,5-disubstituted m-dioxane and the six membered rings in A each are 1,4-phenylene or trans-1,4-cyclohexylene;
- with the proviso that a maximum of two adjacent trans-1,4-cyclohexylene rings are linked directly via a single covalent bond and with the further proviso that ring B or one of the rings in group A is a heterocyclic ring when ring B and group A are linked directly via a single covalent bond;
- and m is the integer 0 or 2.
An electro-optical cell comprising:
- (a) two plate means;
- (b) liquid crystal means disposed between the two plate means and including a compound of the formula;
- ##STR32## wherein R.sup.1 is hydrogen or straight-chain alkyl;
- R.sup.2 is --CN, --R, --COR, --COOR or when R.sup.2 is positioned on an aromatic ring R.sup.2 also can be --OR or --OOCR;
- R is alkyl;
- A is a group with 1 to 4 six-membered rings, these rings being linked directly with one another and with ring B in each case via a single covalent bond or being linked at one or two positions also via --COO--, --OOC-- or --CH.sub.2 --CH.sub.2 --;
- ring B is trans-1,4-cyclohexylene and the six-membered rings in A each are 1,4-phenylene or trans-1,4-cyclohexylene or one of these rings in A also is trans-2,5-disubstituted m-dioxane, 2,5-disubstituted pyrimidine or 3,6-disubstituted pyridazine;
- or ring B is trans-2,5-disubstituted m-dioxane and the six membered rings in A each are 1,4-phenylene or trans-1,4-cyclohexylene;
- with the proviso that a maximum of two adjacent trans-1,4-cyclohexylene rings are linked directly via a single covalent bond and with the further proviso that ring B or one of the rings in group A is a heterocyclic ring when ring B and group A are linked directly via a single covalent bond;
- and m is the integer 0 or 2;
- and
- (c) means for applying an electrical potential to said plate means.
Dependencies are inferred from the claim text.