Hydrothermal synthesis and characterization of one dimensional chain structures of monolacunary Keggin polyoxoanions substituted with copper

摘要

Two novel polymeric polyoxometallates constructed from transition metal substituted heteropolytung-states, [(4,4'bpyH(2))(2)(4,4'bpyH)][PCuW11O39]center dot H2O (1), and [(4,4'bpyH(2))(pyH)(3)][PCuW11O39]center dot 2H(2)O (2), (4,4'bpy = 4,4'bipyridine, py = pyridine) have been synthesized under hydrothermal conditions and characterized by IR, TGA, single crystal X-ray diffraction and magnetic measurements. The product formation showed a high sensitivity toward experimental factors including pH and stirring. Compounds 1 crystallizes in the monoclinic space group P2(1) with a = 13.503(3) angstrom , b = 26.726(5) angstrom, c = 15.168(3) angstrom, beta = 99.61(3)degrees and Z = 4. The second compound also crystallizes in space group P2(1), but with a = 13.519(3) angstrom, b = 20.431(4) angstrom, c = 18.655(4) angstrom, beta = 96.52(3)degrees and Z = 4. Compound 1 exhibits a zigzag chain structure, while compound 2 exhibits a straight chain structure. Compound 2 is the first example of a polyoxometallate containing 1D chains of transition-metal-substituted heteropolytungstate designed with two significantly different organic units as the countercations. The Cu2+ ions in 1 exhibit paramagnetic behavior. (C) 2015 Elsevier B.V. All rights reserved.