Synthesis, magnetic properties, and electronic spectra of complexes of nickel(II) carboxylates with pyridine and related ligands

Abstract

Several adducts of nickel(II) carboxylates with the general formula [NiL₂(O₂CR)₂] have been prepared [R = Me, Ph, 4-ClC₆H₄, and 2-NO₂C₆H₄; L = pyridine (py), 2-methylpyridine (2-Mepy), and quinoline (quin)]. All the complexes have been shown to be six-co-ordinate by magnetochemical and electronic-spectral measurements. Analysis of the tetragonal splitting of their diffuse-reflectance spectra at low temperature and of the polarized single-crystal spectrum of [Ni(py)₂(H₂O)₂(O₂CMe)₂] indicates that all the complexes adopt the trans-configuration except [Ni(2-Mepy)₂(O₂CPh)₂] which shows the cis-configuration. No clear evidence has been found for formation of dimeric complexes.