Synthesis, vibrational study, crystal structure and density functional calculations of [Ni(dien)_2]~(2+) complexes. Configurational and conformational study of [M(dien)_2]~(n+) complexes

摘要

Two new complexes containing the complex cation [Ni(dien)_2]~(2+) (dien = diethylenetriamine) have been synthesised [Ni(dien)_2]CA centre dot 2H_2O (CA = chloranilate) (1) and [Ni(dien)_2][Ni(CN_4)] centre dot 2H_2O (2). The structures of compounds have been determined by single crystal X-ray diffraction methods. In the cationic unit of compound 1, the ligand geometry around nickel(II) is nearly octahedral. Two chelating tridentate diethylenetriamine molecules with terminal amino groups in cis and secondary amino groups in trans position define the s-fac geometry. The conformations of the two independent chelate rings are enantiometric with each other. The nickel atom of [Ni(dien)_2]~(2+) unit in compound 2 also shows a distorted octahedral environment, but the two tridentate dien molecules are coordinated meridionally. Crystallographic observations of fused five-membered ring of bis(dien) complexes, retrieved from Cambridge Structural Database, have been mapped and classified using principal component analysis. Several density functional calculations of the geometry of the s-fac and mer isomers of the complex cation [Ni(dien)_2]~(2+) have been carried out, and the results have been compared to the crystallographic data.