Synthesis and mesogenic properties of N′-(4-acylphenyl)-N-alkylpiperazines

Abstract

One synthesis of N-alkyl-N′-(4-acylphenyl)piperazines and their physical properties have been studied using calorimetric, optical, and X-ray crystallographic methods. The compounds exhibit only smectic phases, the higher-temperature phase being a probable smectic B. The lower-temperature smectic is uniaxial but relatively highly ordered and the measured layer spacing is equal to the calculated molecular length, indicating that the phase is orthogonal. This indicates that the phase is probably a smectic E with random orientational correlation between layers.