Patent ID: 7462427

Claim:
A method of decreasing the melting point, increasing the clearing point, increasing the speed of switching and/or increasing the tilt angle of a liquid crystal mixture, which comprises adding to the mixture a mesogenic compound of formula (I) having a terminal end chain (X,Y) comprising carbon, oxygen or sulphur, which has at least one pendent C 1-4 alkyl or C 1-4 alkoxy groups, or a cycloalkyl or cycloalkoxy ring, arranged no more than 6 atoms from the end of the chain wherein M is a mesogenic core group, and X and Y are selected from a functional group, an optionally substituted alkyl chain, an optionally substituted alkenyl chain, an optionally substituted alkynyl chain or a group of sub-formula (i), provided that at least one of X or Y is a group of sub-formula (i) where R 1 is an alkylene chain optionally interposed with one or more oxygen or sulphur atoms; Z 1 and Z 2 are independently selected from oxygen or sulphur; s and q are independently selected from 0 or 1; m is 1; R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen, C 1-4 alkyl, C 1-4 alkoxy; or R 5 and R 6 or R 2 and R 3 together with the carbon atom to which they are attached form a C 3-7 cycloalkyl or C 3-7 cycloalkoxy group, provided that at least one of the groups R 2 , R 3 , R 5 and R 6 is other than hydrogen, n is 0 or an integer of from 1 to 4, and each group R 4 is independently selected from oxygen, sulphur or a group CR 8 R 9 where R 8 and R 9 are independently selected from hydrogen, C 1-4 alkyl or C 1-4 alkoxy; and R 7 is hydrogen or methyl, provided that where R 7 is methyl, n is other than 4, further provided that neither R 2 nor R 3 are hydrogen when only one of X or Y is a group of sub formula (i) or when R 6 and R 7 do not form a C 3-7 cycloalkyl or C 3-7 cycloalkoxy group.