A novel 1D zigzag chain organic-inorganic polymer with Dawson-type polyoxometalates as building blocks:: synthesis and crystal structure of H1.5[Sm(H2O)8]0.5[Sm(DMF)6(H2O)(α-P2W18O62)]•DMF•3H2O

A novel 1D chain organic-inorganic polymer H-1.5[Sm(H2O)(8)](0.5)[Sm(DMF)(6)(H2O)(alpha-P2W18O62)].DMF.3H(2)O with Dawson-type polyoxometalates as building blocks has been synthesized by reaction of SMCl3, DMF and alpha-H6P2W18O62.nH(2)O in the mixed solution of acetonitrile and water in the bulk ratio of 1:1 and characterized by IR, UV spectra, TG-DTA technique, electrochemical behavior and X-ray single-crystal diffraction. X-ray single-crystal structural analysis displays that the title compound crystallizes in an orthorhombic lattice, P2(1)2(1)2 space group, with a = 23.605(5), b = 30.443(6), c = 14.536(3) Angstrom, alpha = beta = gamma = 90degrees, V = 10446(4) Angstrom(3), Z = 4, R-1 = 0.0493, wR(2) = 0.0783. [Sm(1)(DMF)(6)(H2O)](3+) coordination cation is nine-coordinate with a distorted tricapped trigonal prismatic environment, which is bridged through W-O-Sm(1)-O-W linkages to build an unprecedented 1D zigzag linear chain structure by alternate polyoxometalate anions and metal coordination cations in the polymer, whereas [Sm(2)(H2O)(8)](3+) coordination ion is a discrete unit incorporated into the gaps of the polyoxoanions with an eight-coordinate square antiprismatic geometry. Cyclic voltammetry reveals that the pH of the supporting electrolytic solution has a marked effect on the electrochemical behaviors. (C) 2004 Elsevier B.V. All rights reserved.