Columnar propeller-like 1,3,5-triphenylbenzenes: the missing link of shape-persistent hekates

Soft Matter. 2016 Apr 20;12(16):3730-6. doi: 10.1039/c5sm02489g.

Abstract

Triphenylbenzenes with different substitution patterns at the outer phenyl rings have been successfully synthesised. Sixfold n-alkoxy substitution was insufficient for mesomorphism, but already increasing the number of side chains by three methoxy groups led to liquid crystalline behaviour and mesophase formation. Symmetrical triphenylbenzenes with nine n-alkoxy side chains (≥C9) formed broad enantiotropic mesophases. The symmetry of the liquid crystalline phases was unambiguously determined by X-ray diffraction measurements as Colh and Colho for symmetry-reduced methoxy-alkoxy derivatives and symmetrical nona-alkoxy-triphenylbenzenes, respectively. Based on X-ray diffraction data a stacking model was proposed in which the single molecules aggregate to helical columns forming a mesophase.

Publication types

  • Research Support, Non-U.S. Gov't