Syntheses and lyotropic liquid crystal properties of a series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30

A series of sandwich-type tungstoarsenates heteropoly compounds with As/W ratio of 4/30, Na-16[As4W30M4( H2O)(2)O-112]. XH2O (M = Zn,Cu,Co,Ni,Mn and Cd), have been synthesized for the first time and structurally characterized by elemental analysis, IR and W-183 NMR spectra. The crystal structure of Na-16[As4W30Cu4( H2O)(2)O-112]. 63H(2)O was determined to be a triclinic system, of P (1) over bar symmetry, a = 1.272 1(3) nm, b = 2.451 6(5) nm, c = 2.645 0(5) nm, alpha = 89.90(3)degrees, beta = 77.32(3)degrees, gamma = 89.96(3)degrees, Z = 2. Using tetrahepty lammonium bromide as a phase transfer reagent, [As4W30Cu4( H2O)(2)O-112](16-) was transferred from aqueous solution to organic phase (benzene), and the heteropolyanion lost the coordination water molecules to form the coordination-unsaturated ion. After lactic acid was added to the benzene solution, the coordination-saturation was recovered. By esterification reaction between lactic acid and cholesterin, the latter was attached to the heteropolyanion indirectly. Therefore, a new type of lyotropic liquid crystal was obtained, which was characterized by a polarimicroscope, DSC and variable temperature wide-angle X-ray diffraction.