Mononuclear Cd(II) and Zn(II) complexes with the 1,2-cyclohexanedionedioxime ligand: Preparation and structural characterization

Three mononuclear mixed-ligand Cd(II) and Zn(II) dioximes with the compositions [Cd(HCOO)2(NioxH2)2] (1), [Cd(CH3COO)2(NioxH2)(Im)2]·H2O (2) and [Zn(SO4)(NioxH2)2(H2O)]·DMF·2H2O (3), and the Zn(II) dioximate [Zn(NioxH)2(An)2]·4H2O (4) (where NioxH2 = 1,2-cyclohexanedionedioxime, Im = imidazole, An = aniline, DMF = N,N′-dimethylformamide) were prepared and their structures were determined by single-crystal X-ray crystallography. The structural determination revealed that the coordination geometry around the Cd/Zn centers is distorted octahedral in each complex. In the molecular units 1, 2 and 3, the metal atoms have N4O2 environments, while in complex 4, the Zn(II) cation has an N6 coordination core. The impact of different ligands on the stereochemistry of the metal center is elucidated. The hydrogen bonds, being the driving forces in the generated self-association patterns, are discussed.

Three mononuclear mixed-ligand Cd(II) and Zn(II) dioximes with the compositions [Cd(HCOO)2(NioxH2)2] (1), [Cd(CH3COO)2(NioxH2)(Im)2]·H2O (2), [Zn(SO4)(NioxH2)2(H2O)]·DMF·2H2O (3), and Zn(II) dioximate [Zn(NioxH)2(An)2]·4H2O (4) (where NioxH2 = 1,2-cyclohexanedionedioxime, Im = imidazole, An = aniline, DMF = N,N’-dimethylformamide) were prepared and their structures were determined by single-crystal X-ray crystallography. The impact of different ligands on the stereochemistry of the metal center is elucidated.Figure optionsDownload as PowerPoint slideHighlights
► The first mononuclear Cd(II) and Zn(II) complexes with the 1,2-cyclohexanedionedioxime ligand are reported.
► An unprecedented Zn(II) bis-dioximate is obtained.
► X-ray single crystal diffraction.
► The impact of different ligands on the stereochemistry of the metal center is elucidated.