X-ray diffraction study of n-(alkyloxybenzilidene)-n'-toluidines

Abstract

Liquid crystal n-(alkyloxybenzilidene)-n'-toluidines R−O−C6H4−CH = N−C6H4−CH3 (R = C9H20 1 and C10H21 2) have been investigated by single crystal X-ray structural analysis. The investigation of 2 has been performed at different temperatures (120, 295, 320, and 333 K). Both compounds undergo the crystal–smectic–nematic–isotropic phase transitions. Crystal packing of the compounds consists of alternating loosely packed aliphatic and closely packed aromatic areas that involve weak directional π…π stacking interactions and weak O…H−C hydrogen bonds. A possible mechanism of the phase transitions in these compounds based on peculiarities of their crystal packings is discussed.