LIQUID-CRYSTALLINE PALLADIUM-ISONITRILE AND PLATINUM-ISONITRILE COMPLEXES - SYNTHESIS, MESOMORPHIC PROPERTIES AND MOLECULAR-STRUCTURE

Three series of mesogenic isonitrile derivatives and their platinum(II) (4-6) and palladium(II) (7-9) complexes have been synthesized as a new family of liquid-crystalline materials. The isonitriles themselves exhibit both nematic and smectic mesophases accompanied by considerable decomposition due to their thermal instability. The coordination of the isonitriles to a metal results in a large increase in their thermal stability, and the platinum and palladium complexes show mesomorphic properties in a high and broad temperature range without any decomposition except a few palladium complexes. The liquid-crystalline complex PtI2(CNC6H4C6H4OC7H15)2 (6, X = I, n = 7) has been crystallographically characterised and the relationships between structure and property of the metal-isonitrile complexes are discussed.