Liquid crystals based on pseudohalogold(I) isocyanide complexes

Rod-like complexes [AuX(C=NR)] (X=CN, SCN; R=C6H4OCnH2n+1-p, C6H4C6H4OCnH2n+1-p (n=4, 6, 8, 10, 12); 2-F-4-OC12H25C6H3; 3-F-4-OC12H25C6H3; and 3,4,5-(OC10H21)(3)C6H2) have been prepared by reaction of [AuCl(C=NR)] with KSCN or AgCN. The free phenyl isocyanides are not liquid crystals, but all the gold complexes display wide ranges of smectic A (S-A) mesophases, except the compound [Au(SCN)(CNC6H4OC4H9)] which is not liquid crystalline, and the trialkoxyphenyl derivatives which show columnar hexagonal phases at room temperature. The determining influence of the electronic and structural characteristics of both the pseudohalo and isocyanide ligands on the stabilization and type of mesophase is discussed.