Hydrothermal Synthesis and Structure of a Novel Binuclear Molybdenum Complex with Oxalate Ligand, （enH2） {NH4[Co（en）3] [Mo2O7（C2O4）] }2.2H2O~

The title complex (enH2){NH4[Co(en)3][Mo2O7(C2O4)]}2.2H2O (C18H70Co2Mo4N16O24. Mr = 1396.52) was obtained under hydrothermal conditions and its crystal structure hasbeen determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic system, spacegroup P21/c with a = 17.8023(8), b = 7.7527(4), c = 16.9781(4)(A°), β= 103.878(7)°, V= 2274.8(2)(A°)3, Dc = 2.039 g/cm^3, Z = 2, μ(MoKα) = 1.878 mm^-^1 and F(000) = 1408. The final R = 0.0410 and wR= 0.1070 for 4065 observed reflections with 1≥2σ(I). The crystal structure is composed of binuclear [Mo2O7(C2O4)]^4^- anions, complex [Co(en)3]^2^+ cations, protonated ethylenediamine cations,ammonium cations and crystal water molecules, which are held together into a three-dimensional network via hydrogen-bonding interactions. The binuclear structure of [Mo2O7(C2O4)]^4^- consist of one MoO4 and one MoO6 octahedra through sharing a bridging oxygen atom, where the oxalateligand acts as a bidentate ligand coordinating to the octahedral molybdenum atom though twodeprotonated corboxylate groups.