Synthesis, Structure and Property of Mixed-valence Tetranuclear Copper Complex [Cu2L2]•[Cu(pht)2]2

The title complex [CuL2]center dot[Cu(pht)(2)](2) (Hpht = 5,5-diphenylhydantoin, i.e. phenytoin; L = N-(3-aminopropyl)diethanolamine) has been synthesized solvent-thermally and characterized by elemental analysis, IR, TG-DSC and single-crystal X-ray diffraction. The crystal of the copper complex belongs to monoclinic system with space group P2(1)/n, a=0.9240(1) nm, b=2.4559(2) nm, c=1.5572(2) nm, alpha=gamma= 90 degrees, beta=97.489(2)degrees, V=3.5035(7) nm(3), D-c=1.499 Mg/m(3) (g/cm(3)), Z=2, F(000)=1636, mu=1.270 mm(-1), R-1=0.0503, wR(2)=0.1135 [I>2 sigma(I)] and GOF=1.014. The XPS and single-crystal X-ray diffraction data demonstrated that the complex is a mixed valence one, including two Cu(1) and two Cu(II) metal centers. The Cu(I) atom is coordinated by two nitrogen atoms from two phenytoin ligands, and the angle of N-Cu(1)-N was 177.1 degrees. The Cu(II) atom adopts a distorted CuN2O3 square-pyramidal configuration when coordinated with two L ligands, dinuclear cation is constructed by the connection of Cu(II) and O atoms from the bridging hydroxyl groups of L. The complex was valued for its antimicrobial activity by diffusion test in vitro. It was found to be active against the three test bacterial organisms. The interaction between the complex and CT-DNA was studied by UV spectroscopy, fluorescence spectroscopy and viscosity measurements,