The Secretary of State for Defence in Her Britannic Majesty's Government

Imperial Chemical Industries Limited

David J Thompson

Edward P Raynes

Kenneth J Harrison

Frances C Saunders

Damien Gerard McDonnell

David F Newton

Paul F Gordon

Anthony J Hughes

A metal dithiene of the formula: ##STR1## wherein R.sup.1 is C.sub.3 to C.sub.20 alkyl;

Dithiene derivative

A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye characterized in that the dye comprises at least one anthraquinone compound free from water-solubilizing and ionic substituents and having the formula: ##STR1## wherein each of R and R.sup.1 independently represents an n-alkyl group having from 4 to 7 carbon atoms inclusive and wherein each of R.sup.2 and R.sup.3 is independently selected from hydrogen and alkyl groups having from 1 to 4 carbon atoms inclusive.

Liquid crystal materials containing pleochroic anthraquinone dyes

A material suitable for a guest-host liquid crystal device comprises a soion of a liquid crystal material and a pleochroic dye where in the pleochroic dye comprises at least one anthrquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein Q is NH.sub.2, OH, alkyl, aryl, NO.sub.2 or halo;

Liquid crystal compositions with pleochroic anthraquines dyes

New pleochroic anthraquinones, suitable for use in colored liquid crystal displays based upon the guest-host effect, of the formula: ##STR1## wherein R & R.sup.1, each independently, represents C.sub.4-7 -n-alkyl; and

Anthraquinone compounds

A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein one of X and Y is OH and the other is NHR wherein R is H or lower alkyl; each of R.sub.1 and R.sub.2 independently represents alkyl, aryl, aralkyl, alkoxy or --NR.sub.3 R.sub.4 wherein each of R.sub.3 and R.sub.4 is independently H or lower alkyl, provided that R.sub.2 is always adjacent to an OH group.

A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one anthraquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein P is OH or NH.sub.2 ; each group X.sup.A is independently selected from OH, NO.sub.2, SR and NZ.sub.1 Z.sub.2 provided that one group X.sup.A is SR and the other group X.sup.A is OH, NO.sub.2 or NZ.sub.1 Z.sub.2 is 1 or 2; each group Q.sub.1 is independently alkyl having from 1 to 20 carbon atoms; each group R is independently selected from alkyl having from 1 to 20 carbon atoms, aryl having up to 15 carbon atoms and cycloalkyl having from 4 to 8 carbon atoms.

Organic materials

An anthraquinone dye free from water-solubilizing and ionic substituents of the general formula: ##STR1## wherein Q is NH.sub.2, OH, alkyl, aryl, NO.sub.2 or halo;

Pleochroic anthraquinone dyes

An anthraquinone dye from water-solubilizing and ionic substituents of the general formula: ##STR1## wherein Q is NH.sub.2, OH, alkyl, aryl, NO.sub.2 or halo;

A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein: R represents a group selected from optionally substituted alkyl and optionally substituted monocyclic aryl;

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Whitefield, United Kingdom

David J Thompson