Non additivity of ligand effects on 59Co NMR chemical shifts in Co(III) complex compounds

Abstract

59Co chemical shift in a number of Co(III) complexes of the type CoA6-xBx(x = 0–6, A and B denote corresponding ligators) containing mono- and/or bidentate ligands, was measured. In almost all cases studied it was found that chemical shift appear at lower field than expected on the basis of the Rule on Additivity of Ligand Effects on 59Co chemical shift. The non additivity of the ligand effects on 59Co chemical shift has been discussed in terms of ligand field theory. It was shown that negative deviations from additivity has to be expected.