Thermotropic mesomorphism in a branched chain copper(II) carboxylate and its pyrazine complex

Abstract

The thermotropic mesomorphism of tetrakis(μ-(2,2-(dioctyl(acetato))-O,O′)bis-[copper(II)] has been investigated by optical microscopy and X-ray diffraction. This compound was found to form a hexagonal discotic phase analogous to those reported for the copper(II) salts of n-alkanoic acids, but in contrast to these materials the mesophase of the branched chain compound was found to extend to below room temperature. Complexation of the copper(II) branched chain carboxylate with the difunctional ligands pyrazine and 4,4′-dipyridyl resulted in liquid-crystalline materials whose mesophase structure could not be established. The possibility of these complexes existing as polymeric/oligomeric entities is discussed.