A New Heteropolyoxotungstate with a Three-dimensional All-inorganic Framework [(C2H4N2)4(P4Co3W4O28H6)(H2C2O4)]n

A new heteropolyoxotungstate [(C2H4N2)(4)(P4Co3W4O28H6)(H2C2O4)](n) with a three-dimensional framework was hydrothermally synthesized. The compound crystallizes in a tetragonal system, space group I41/a with a = 17.1006(17), b = 17.1006(7), c = 10.7525(5) angstrom, V = 3144.2(2) angstrom(3), Z = 4, D-c = 3.795 g.cm(-3), F(000) = 3300, MoK alpha (lambda = 0.71073 angstrom), mu = 16.460 mm(-1), the final R = 0.0335 and wR = 0.0776. In the heteropolyoxotungstate, tungsten-oxygen octahedra are linked by sharing two cis-vertexes into an infinite helical chain extending along the c axis. Cobalt atoms in the octahedral geometry act as the linkers of these chains, forming a three-dimensional framework. The cobalt and phosphorus atoms in the tetrahedral geometry play a role in stabilizing the three-dimensional framework. Ethylenediamine molecules are polymerized into organic chains which locate in the interspaces of the framework in the way of interwinding with the W-O chains.