Effect of alkoxy chains on the mesomorphic properties of (p-alkoxy)tetrafluoroarylgold(I) isocyanide complexes

Rod-like gold(I) complexes [Au(C6F4OCmH2m+1)(CNC6H4O(O)CC6H4OCnH2n+1)] [m=4, 8; n=4, 6, 8, 10] have been prepared and their liquid crystal behavior studied. All the tetrafluorophenylgold(I) derivatives described are liquid crystals and their thermal stability is high, even in the isotropic state. The variation in thermal properties of tetrafluorophenylgold(I) complexes is very regular. When a short alkoxy chain is placed in the tetrafluorophenyl group (m=4), both smectic A and nematic phases are observed for shorter alkoxy substituents in the isocyanide ligand (n=4, 6). For longer chain-lengths (n=8, 10), only smectic A phases are observed. When the alkoxy substituent in the tetrafluorophenyl group is longer (m=8), both SmA and SmC phases are obtained, irrespective of the chain-lengths of the isocyanide ligand.