Ionic silver amino complexes displaying liquid crystalline behavior close to room temperature

The liquid crystalline properties of a series of ionic silver complexes [AS (NH(2)n-CnH2n+1)(2)]X (X = NO3, n = 6, 8, 10, 12, 14; X = BF4, n = 8,10, 12 , 14), derived from silver nitrate or tetrafluoroborate and aliphatic amine s, have been investigated by optical microscopy, DSC, and X-ray diffraction . The materials exhibit a birefringent fluid phase identified as a smectic A mesophase by optical microscopy and X-ray diffraction. Some of the comple xes are Liquid crystalline at temperatures close to room temperature. The X -ray results are consistent with the existence in the mesophase of a bilaye r organization. The silver cations adopt a U-shape, which allows for the ad option of this bilayer arrangement, with alternating ionic and apolar regio ns and a short-range square-planar array inside the cationic sublayers. The thermodynamic parameters suggest that the melting transition clearly invol ves only disorder (melting) of the chains, whereas the clearing transition implies breaking the anion-cation arrangement.