(R)- and (S)-enantiomer composition represented by the formula (I) having sufficient high optical purity for exhibiting optically tristable states in S*(3) phase; ##STR1## wherein Ra means a C.sub.5 -C.sub.14 alkyl group or a C.sub.5 -C.sub.14 alkoxy group, preferably a C.sub.5 -C.sub.14 alkyl group, Rb means a C.sub.4 -C.sub.12 normal alkyl group or a C.sub.4 -C.sub.12 branched alkyl group, X means a ##STR2## group or a ##STR3## group, Z means a fluorine containing alkyl group, preferably a trifluoromethyl group and * shows an optically active carbon.
Liquid crystal compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 each is a C.sub.1-18 alkyl group or an aralkyl group, R' is a haloalkyl group, X is --0--, --CO--, --COO-- or direct bond, Y is --COO--, --OCO-- or --CH.sub.2 O--, (A) and (B) each is ##STR2## and p and l each is zero or one.
Photochromic antiferroelectric liquid crystals containing a diazene moiety were synthesized for the first time, and their photochemical switching behaviors were studied.
首次合成了含有二氮烯基团的彩色光致抗铁电液晶,并研究了它们的光化学开关行为。
Partially fluorinated liquid crystal material
申请人:——
公开号:US20030017278A1
公开(公告)日:2003-01-23
The invention provides LC compositions that exhibit V-shaped switching when aligned in an analog device configuration and exhibit bistability when aligned in a bookshelf-type device configuration. The invention more specifically provides LC compositions of formula 1 and particularly chiral nonracemic compounds of formula 1 which exhibit bistable switching as well as V-shaped switching when aligned in appropriate device configurations. The invention also provides methods of using the compounds of the invention in making LC compositions and electooptical devices comprising an aligned layer of the compositions of this invention.
Highly Enantioselective Transfer Hydrogenation of Fluoroalkyl Ketones
作者:Damjan Šterk、Michel Stephan、Barbara Mohar
DOI:10.1021/ol062358r
日期:2006.12.1
[Structure: see text] The asymmetric transferhydrogenation of fluoroalkyl ketones mediated by [Ru(eta6-arene)((S,S)-R2NSO2DPEN)] catalysts using HCO2H-Et3N afforded the corresponding alcohols with high ee's and in excellent yields.