Formation and dissociation mechanism of amide complexes III. Water substitution as the rate limiting factor for the interconversion of Cu2+ complexes with neutral and deprotonated amide groups

Abstract

AbstractThe protonation and deprotonation rates of the coordinated amide group in the Cu2+ complexes with Nα‐(2‐pyridyl‐methyl)‐glycinamide (I) and Nα‐(2‐pyridyl‐methyl)‐glycineethylamide (II) have been studied by stopped flow techniques. It is shown that the rate determining step of the formation of the complex with the deprotonated amide group is given by the rate of water dissociation from Cu2+. Weaker bases than OH− or stronger acids than water can react by a different path, in which the proton transfer and/or the rotation from the O‐co‐ordinated into the N‐co‐ordinated form and vice versa is rate determining.