Thermodynamics of metal-ligand bond formation. III. Adducts of heterocyclic bases with Bis(N-nitroso-N-phenylhydroxylaminato)copper(II)

Abstract

The copper(II) complex of N-nitroso-N-phenylhydroxylamine (copper cupferrate) reacts with heterocyclic bases in benzene solution to form 1 : 1-adducts. Enthalpies and entropies of adduct formation with a range of bases have been determined by thermometric titration. The results, which are similar to those obtained with copper(II) complexes of β-diketones, reveal two isoequilibrium series for sterically hindered and unhindered bases, and indicate that the effect of the steric hindrance is probably to restrict rotation of the base molecule about the newly formed metal-ligand bond.