Electronic studies of Cu(II) complexes of amino acids—V: Bonding in some Cu(II) X-Schiff base coordination compounds

Abstract

Three series of Cu and Cu:Zn coordination compounds of X-salicylaldehyde-amino acid Schiff bases were prepared with X  4OH, H, 5NO 2, 5Cl and glycine, alanine and phenylglycine. The magnetic and spectral parameters were obtained and utilized in the calculation of molecular orbital coefficients for these coordination compounds. Simple Hückel molecular orbital calculations of the imine model (I) and carbanion model (II) were used to rationalized the observed trends. It was observed that the R  CH 3 and X  OH, H, NO 2 and Cl were fitted well by model (I) while the R  H and C 6H 5 and X  NO 2 were better correlated with model (II), showing the C(10)-H bond in these latter compounds to be particularly labile.