Liquid-crystalline palladium– and platinum–isonitrile complexes: synthesis, mesomorphic properties and molecular structure

Abstract

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 Ptl₂(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.