Water exchange on metal ions: experiments and simulations

The water exchange reaction between coordination shells around metal ions in aqueous solution is a fundamental reaction in understanding the reactivity of these ions in chemical and biological systems. The results reviewed in this paper demonstrate the complementary of experimental studies and computer simulations or quantum chemical calculations performed on such systems. Due to the large range of exchange rate constants, a variety of experimental and different computer techniques have to be applied. Very fast exchange reactions between first and second cc ordination shell and between second shell and bulk solvent can be simulated by classical molecular dynamics technique. Reaction pathways for water exchange on metal ions with a less labile first coordination shell can be followed by calculation of clearly defined transition states. Success and shortcomings of the techniques are discussed by means of recent publications. (C) 1999 Elsevier Science S.A. AU rights reserved.