Pyrophosphate(ppi),as an extremely significant biological anion,play a key role in hydrolysis and synthesis of ATP and DNA and several major metabolic processes[1].In bioinorganic systems,benzimidazole groups are commonly used as binding sites to mimic active enzymes.Pyrophosphate has a variety of coordination modes and strong coordination ability,which can be effectively recognized and combined by metal ions[2].We synthesized complexes [Fe2(ntb)2(P2O7)]·(ClO4)2·CH3OH·H2O(1)and [Ni2(ntb)2(P2O7)H2O]·8.75H2O(2),using tris(3-benzimidazolylmethyl)amine(ntb)ligand and pyrophosphate.The structure was characterized by IR and X-ray single crystal diffraction.The coordination environment of both complexes is distorted octahedron.And the metal centers of the two complexes are bridged by pyrophosphate.The difference is existed in the ntb coordination sites of complex 2 on both sides.The Ni2 center has one less nitrogen atom coordination site than the Ni1 center,which is related to the extension direction of the benzimidazole ring.According to the coordination environment and the single-crystal analysis,complex 1 can be described as the structure model of phosphatase in some degree and more details are being explored.