Synthesis and Mesogenic Properties of N-<i>n</i>-alkyl-N′-(4-<i>n</i>-Pentyloxyphenyl)-Piperazines

Abstract

Abstract The N-n-alkyl-N′-(4-n-pentyloxyphenyl)-piperazines (4) exhibit ordered smectic phases at temperatures below 100°C. For 3, 4, 5 and 6 carbons in the alkyl chain, two smectic phases are present and for 7, 8 and 9 carbons only one smectic phase is present. The ΔH values for 4, 5, 6 and 7 carbons are anomalous. From optical and X-ray data, the smectic phases are identified as probably smectic E and B phases.