A novel nickel complex with 3-Hydroxyflavone: Synthesis, CrystalStructure and reactivity towards O2 of Ni4(C15O3H9)4(CH3O)4(H2O)4

A novel tetranuclear nickel(II)-flavonolate complex [Ni-4(II)(fla)(4)(CH3O)(4)(H2O)(4)] (flaH: 3-Hydroxyflavone, flavonol) was synthesized. Its crystal structure and spectroscopic features have been investigated in details by physicochemical methods and single crystal X-ray diffraction. Different from other mononuclear metalflavonolate complexes, this complex demonstrates a cluster molecular structure which has four Ni-II centers, and each Ni-II centre is coordinated by a bidentate flavonolate, three methanol and a water molecule. The crystal of this complex is tetragonal crystal system: space group I 41/a, a = 24.4361(14), b = 24.4361(14), c = 12.7972 (14), alpha = beta = gamma = 90 degrees V = 7641.5 (12), Z = 4. The complex can react with O-2, in other words, it has enzymatic reactivity just like enzyme-substrate model of quercetin 2,3-dioxygenase, and the reaction products are similar with the other reported enzyme-substrate models.