The stabilization of smectic A phases in mixtures of twinned-calamitic, metal organic complexes with 2,4,7-trinitro-9-fluorenone

The liquid crystal properties of binary mixtures of copper- and palladium-containing, twinnedcalamitic, metal organic complexes with the electron acceptor 2,4,7-trinitro-9-fluorenone (TNF) are reported. The smectic A to isotropic transition temperature of the pure metal organic component is increased on mixing. Furthermore, only smectic A behaviour is exhibited by the mixtures compared with smectic A and C phases for the pure metal organic complexes. The stabilization of the smectic A phase in these mixtures is found to be due to a weak charge transfer type interaction.