Nickel(II) complexes of aromatic aldehyde oximes

Abstract

The electronic and i.r. spectra of nickel(II) complexes of pyridine-2-carbaldehyde oxime (pa), quinoline-2-carbaldehyde oxime (qa), isoquinoline-3-carbaldehyde oxime (iqa), and pyridine-2-carbaldehyde O-methyl oxime (pam) are described. On the basis of these physical properties a dimeric cis-octahedral structure is suggested for the complexes NiX₂L₂(where X = Cl or Br, L = pa or qa; or X = Cl, L = iqa or pam), whereas NiBr₂(pam)₂ appears to be monomeric with a trans-octahedral structure. The acetato-complexes Ni(AcO)₂(iqa)₂,H₂O and Ni(AcO)₂(pa)₂ appear to have a monomeric cis-octahedral structure involving intramolecular hydrogen bonding between the OH of the oxime group and an acetate group.