Abstract

The synthesis, characterization and mesomorphic properties of gold(I) and silver(I) ionic isocyanide complexes [Au(CNR)₂]Y [R = C₆H₄OC_nH_2n + 1, C₆H₄C₆H₄OC_nH_2n + 1, C₆H₂(3,4,5-OC_nH_2n + 1)₃; Y = PF₆⁻, BF₄⁻ (n = 4, 8, 12), Y = NO₃⁻ (n = 8)] and [Ag(CNR)₂]Y [R = C₆H₄OC_nH_2n + 1 (n = 8, 12), C₆H₄C₆H₄OC_nH_2n + 1 (n = 4, 8, 12), C₆H₂(3,4,5-OC_nH_2n + 1)₃ (n = 4, 8 12); Y = NO₃⁻, BF₄⁻] are described. The free phenyl and 3,4,5-trialkoxyphenyl isocyanides are not liquid crystals but most of the gold and silver derivatives prepared are mesogens. Only the nitrate series of gold, which decompose on melting, and the complexes [Au(CNR)₂]PF₆ [R = C₆H₄OC₄H₉, C₆H₂(3,4,5-OC₄H₉)₃] do not display mesogenic behaviour. The phenyl and biphenyl gold derivatives show smectic A phases and the analogous silver complexes display SmA and SmC mesophases, while the 3,4,5-trialkoxyphenyl isocyanide complexes of gold and silver show hexagonal columnar mesophases.

The influence of the metal atom, the anion and the isocyanide on mesogenic behaviour for these kinds of complexes is discussed.