Butterfly-mesogens: para-cyclophane based macrocyclic metallomesogens forming smectic and columnar liquid crystalline phases

Abstract

The combination of two different molecular architectures, the rather rod-like para-cyclophanes and two half disc-like 1,3-diketonate units fused viaortho-palladation leads to new liquid crystalline materials with a quite unusual molecular shape. By increasing the number of attached alkyl chains a discontinuous transition from a lamellar to a columnar organisation of the molecules was observed. Compounds with twelve alkyl chains are the first para-cyclophane derivatives that show thermotropic columnar mesophase behaviour.