Temperature Dependent Sign Reversal of the Optical Anisotropy in Pyramidic Mesophases

Abstract

Hexasubstituted tribenzocyclononene derivatives with R = -OC(O)C₆H₄C_nH_2n+i and R = -OC(O)C₆H₄OC_nH_2n+1 possess enantiotropic pyramidic mesophases. These mesophases exhibit an uncommon feature in that their optical anisotropy changes sign as function of temperature within the mesophase region. It is suggested that this effect reflects conformational changes involving the side chain benzene ring.