Stereoselectivity and mechanism of Cu2+ transfer between chiral, multidentate ligands

Abstract

The ligand-exchange kinetics between the enantiomers of [Cu(alamp)] or [Cu(promp)] and (S)-pdta are measured by CD spectroscopy; three different reaction intermediates are proposed, involving the three different states of N-protonation of pdta; at pH < 7 an associative mechanism involving a cage-like, hydrogen-bonded intermediate is suggested for [Cu(alamp)] in which the metal ion is transferred in a single rate limiting step from one ligand to the other.