Use of nuclear magnetic resonance contact shifts to study the stability of paramagnetic coordination complexes. Bis(2,4-pentanedionato)nickel(II) complexes of substituted anilines

Article abstract of DOI:10.1021/ic50088a043

The use of nuclear magnetic resonance contact shifts of ligands in paramagnetic coordination complexes to measure relative stability constants for the complexes is demonstrated. Bis(2,4-pentanedionato)nickel(II) complexes of meta-, para-, and N-substituted anilines are investigated. The effects of meta and para substituents on the stability constants are well described by a blend of the inductive and resonance effect parameters σ_I and σ_R. N-Methylation decreases the stability of the complex. N-Methyl contact shifts are strongly dependent on the meta or para substituents and linearly related to the stability of the complex.