Hydrothermal synthesis and characterization of an asymmetric binuclear molybdenum complex with oxalate ligand, NH4(enH2)0.5[Co(en)3][Mo2O7(C2O4)]•H2O

A new binuclear complex NH4(enH(2))(0.5)[Co(en)(3)][Mo2O7(C2O4)].H2O was obtained from the hydrothermal reaction of (NH4)(6)Mo7O24.4H(2)O, CoC2O4.2H(2)O, ethylenediamine and H2O at 120 C, and characterized by single crystal X-ray diffraction and spectroscopic methods. The crystal structure is composed of dimeric [Mo2O7(C2O4)](4-) anions, complex [Co(en)(3)](2+) cations, ethylenediamine cations, ammonium cations and crystallization water molecules, which are held together to an extensive three-dimensional network via hydrogen-bonding interactions. The dimeric structure of [Mo2O7(C2O4)](4-) is formed by one MoO4 tetrahedron and one MoO6 octahedron through sharing a bridging oxygen atom, where oxalate acts as a bidentate ligand coordinating to the octahedral molybdenum atom though two deprotonated corboxylate groups. It is shown that the title compound possesses well-separated paramagnetic Co2+ centers. (C) 2003 Elsevier Science B.V. All rights reserved.