Organosilylalkyl or organosilylalkenyl compounds, process for preparing them and their use in liquid-crystalline mixtures

摘要

The novel silylalkyl or silylalkenyl compounds correspond to the general formula (I) <IMAGE> (I) Here the symbols A1, A2, A3 denote aromatic or heteroaromatic molecular units such as 1,4-phenylene or pyrimidine-2,5-diyl which are combined via a single bond (for k, m=0) or via functional groups M1,M2 such as CO-O or CH2-O; j, k, l, m, n are zero or 1 (j+l+n=2 or 3). The radicals R2, R3, R4, R5 are hydrogen or alkyl/alkenyl, cycloalkyl, and the radicals R6, R7, R8 have a comparable meaning (hydrogen); R1 is alkyl/alkenyl or one of the substituents known from LC chemistry such as an alpha -haloalkanoic radical. In some cases compounds have wide and polymorphous liquid crystalline phases.