6533b82afe1ef96bd128c133

RESEARCH PRODUCT

Ni(II) and Zn(II) complexes with cinoxacin. Synthesis and characterization of M(Cx)2(DMSO)n(H2O)m (n=0, 2; m=2, 4). Crystal structures of [M(Cx)2(DMSO)2]·4H2O (M=Ni(II), Zn(II))

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Abstract New metal complexes of cinoxacin (HCx=1-ethyl-l,4-dihydro-4-oxo(1,3)dioxolo(4,5-g)cinnoline-3-carboxylic acid) were synthesized, isolated as [Zn(Cx)2(DMSO)2]·4H2O, [Ni(Cx)2(DMSO)2]·4H2O, Zn(Cx)2·4H20 and Ni(Cx)2·2H2O, and characterized by elemental analysis, TG studies, IR and UVVis spectroscopic techniques. The crystal and molecular structures of the complexes [M(Cx)2(DMSO)2]·4H2O (M=Zn(II), Ni(II)) have been determined by X-ray structure analysis. The crystals of [Zn(Cx)2(DMSO)2]·4H2O are triclinic, space group P 1 with unit cell dimensions a=8.950(4), b=9.168(5), c=11.650(6) A, α=69.06(1), β=82.05(1), γ=75.63(1)°, V=863.6(8) A3; [Ni(Cx)2(DMSO)2]·4H20 is monoclinic, space group P21/n, a=10.684(2), b=7.729(1), c=20.862(1) A, β=104.66(1)°, V=1666.7(3) A3. Both structures consist of monomeric [M(Cx)2(DMSO)2] units, and uncoordinated water molecules that provide crystalline stability through a network of hydrogen bond interactions. The metal ion is placed in a crystallographic inversion centre, which relates to the two bidentate cinoxacinate ligands that bind through one carboxylate oxygen atom and the exocyclic carbonyl oxygen atom. The octahedral coordination environment is completed by two dimethyl sulfoxide molecules coordinated via the oxygen atom. The characterization of the Ni(Cx)2·2H2O complex suggests an octahedral arrangement to the Ni(II) ion.