Exchange reactions of some 8-hydroxyquinoline complexes

Abstract

Information about the lability of complexes, Lewis and Wilkins Modern Co-ordination Chemistry, P.138. and hence the electronic state of the metal atom, can often be obtained from isotopic exchange reactions. An isotopic exchange reaction essentially involves no overall heat content change, and the free energy of the reaction is derived from the entropy change for the isotopic mixing. The free energy change is always negative. The equilibrium state for any exchange corresponds to complete isotopic mixing between AB and AB*, the two "reactants", a small correction being made for equilibrium effects Chem. Rev. 57 2 P. 819. The rate at which this equilibrium is approached is a direct measure of the lability of the complex.