Relation between the torsion angles of acetate chelate rings and the deuteron nuclear magnetic resonance chemical shifts for polyamine-N-carboxylatochromate(III) complexes

Abstract

Deuteron n.m.r. spectra were examined for a series of multidentate polyamine-N-carboxylato complexes with cis-CrN₂O₄ chromophores in solution. The isotropic contact shifts for the deuteriated acetate methylenes in the paramagnetic chromium(III) complexes were compared with the glycinato chelate ring conformations obtained from X-ray structure analyses. There is a fair correlation between the chemical shifts and the torsion angles in the Cr–N–C–C(O) fragment of the acetate(glycinato) rings according to a Karplus-like or cos²θ relation.