SYNTHESIS AND CHARACTERISATION OF SOME NICKEL(II) β-KETOAMINES AND THEIR ADDUCTS WITH 2,2′-BIPYRIDINE AND 1,10-PHENANTHROLINE

ABSTRACT

A series of nickel(II) β-ketoimine complexes, {Ni[CH₃-C(O)CHC(CH₃)NR]₂, R=CH₃, C₄H₉}, and ketoiminates, {Ni[CH₃C(O)CH(CH₃)C(-N(CH₂)_nN-)C(CH₃)CHC(O)CH₃], n=2, 6, 8, 9}, and their adducts with 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) have been synthesized and characterized using elemental analyses, magnetic susceptibility, conductivity, infrared and electronic spectral measurements. The ketoimine ligands coordinate to the nickel atom in a bidentate fashion using the N₂O₂ chromophore. A range of stereochemistries was observed for the nickel(II) ketoiminates from four-coordinate tetrahedral and square-planar geometry to six-coordinate octahedral geometry. Conductivity measurements indicate that the compounds are non-electrolytes. The influence of bridging chain lengthening on the adopted geometry is discussed and possible structures for the compounds are suggested.

ACKNOWLEDGMENT

We express our gratitude to the Microanalytical Laboratory, Institut für Anorganische Chemie, Universität, Tübingen, Germany, for elemental analyses and the University of Ibadan for a Senate Research Grant. OAO has benefited from an extended leave of absence from Ladoke Akintola University of Technology, Ogbomoso, Nigeria.