| abstract |
Geminate dimethylalkyl compounds with general formula (I) can be used to good advantage in liquid crystalline mixtures. In the formula, R?1 is, for example, a straight or branched chain (with or without asymmetric C-atom) alkyl or alkenyl with 2 to 16 C-atoms; A?1, A?2, A?3 are the same or different and represent, for example, 1.4-phenylene, 1.4-cyclohexylene or pyrimidin-2.5-diyl; M?1, M?2 are the same or different and represent CO-O, O-CO; G is, for example, the same or different straight or branched chain alkylene with 1 to 16 C-atoms; k, l, m, n are zero or 1; and R?6 is straight-chain alkyl with 1 to 10 C-atoms. The compounds described offer a lower point of fusion in liquid crystalline mixtures, a shift in the thermal limit of the Sc?-phase in ferroelectric mixtures, and other improvements in important electro-optical characteristics. |