Use of liquid-crystal 5-phenylpyrimidine derivatives as components of smectic liquid-crystal mixtures

摘要

The compounds of the general formula (I) ##STR1## are particularly highly suitable as components of smectic, liquid-crystal mixtures, the symbols having the following meaning: R.sup.1 and R.sup.2 denote identical or different, straight-chain or branched alkyl or alkenyl groups which can contain asymmetric carbon atoms, containing 2 to 16 carbon atoms, in which one or more non-adjacent --CH.sub.2 -- groups can be replaced by --O-- and/or --S--, --A and --B each denote group ##STR2## in which the radicals R.sup.1, R.sup.2, in each case, are situated at the phenylene part of --A, --B and m and n denote 0 or 1, but m+n is always zero or 1.