Patent ID: 7261836

Claim:
A phenylethanediol derivative, characterized in that the phenylethanediol derivative comprises at least one photo-convertible group suitable for adjusting the helical twisting power of the phenylethanediol derivative, wherein the phenylethanediol has the formula wherein A stands for a bond or a p-phenylene group; B and B′ are independently (O) p —C o H 2o —O—CO—CR′═CH 2 , o being 2-12, p being 0 or 1, and R′ being H or CH 3 ; P stands for a CH 2 or a C═O group; Q and Q′ are independently selected from H, C1-C3 alkyl, C1-C3 alkoxy, halogen, and CN; n is an integer from 1 to 3; and m is an integer from 0 to 2.