Ni(phen)32+–Co(phen)32+ system: evaluation of the dipolar proton magnetic resonance shift contribution in paramagnetic cobalt(II) complexes

Abstract

¹ H N.m.r. spectra of the paramagnetic trisphenanthroline-nickel(II) and -cobalt(II) complexes are reported. The observed isotropic shifts are attributed to both σ- and π-spin delocalization and to contributing dipolar shifts in the case of the cobalt species. The ratio method ¹ has been employed as a means of estimating the dipolar shift contributions, and the general applicability and limitations of the method as it pertains to phenanthroline and other heterocyclic amine ligands is discussed.