Transition metal polyaminecarboxylate

ADVANCES IN THE MECHANISTIC UNDERSTANDING OF SELECTED REACTIONS OF TRANSITION METAL POLYAMINECARBOXYLATE COMPLEXES... 

An excellent method to investigate the rate and mechanism of water exchange on transition metal polyaminecarboxylate complexes are temperatiue- and pressure-dependent NMR measurements. The active species in the water exchange for Fe Fe, and Mn is a seven-coordinate mono-aqua species. The exchange takes place between a coordinated and a bulk water molecule (Eq. (5)). 

This review deals with the reaction mechanisms of polya-minecarboxylate complexes of different transition metals such as Fe, Mn, Ni, and Ru. Three types of chemical processes are treated, viz. water-exchange reactions, the binding of NO, and the activation of peroxides. In each case, the natiu-e of the polyaminecarboxylate chelate and its influence on the imderly-ing reaction mechanism are considered. In general, the complexes are either six- or seven-coordinate and all contain a coordinated water molecule. The lability of the latter is controlled by the nature of the polyaminecarboxylate chelate and the oxidation state of the metal ion. The binding of NO and the activation of peroxide are in turn controlled by the lability of the coordinated water molecule that is displaced during the interaction with these small molecules. 

---