Electron spin resonance studies of axial ligation to cobalt(II) complexes. Part 1. Some oxo-, thio-, and seleno-Schiff bases

Abstract

Electron spin resonance spectra have been recorded for frozen solutions of five different low-spin cobalt(II) Schiff-base complexes having either oxygen, sulphur, or selenium as two of the co-ordinating atoms and with a range of up to seven phosphines or phosphite ligands co-ordinated in the axial position. From analysis of the cobalt and phosphorus hyperfine tensors and the g tensor, the bonding parameters have been calculated. Correlations are made in an attempt to distinguish between electronic and steric effects in the co-ordination of the phosphorus base. Internal bond angles in the phosphorus ligand have been calculated.