Water exchange dynamics of manganese(II), cobalt(II), and nickel(II) ions in aqueous solution.

The first row transition metal ions Mn2+, Co2+, and Ni2+ have been studied by classical umbrella sampling molecular dynamics simulations. The water exchange mechanisms, estimates of reaction rates, as well as structural changes during the activation process are discussed. Mn2+ was found to react via an I-A mechanism, whereas Co2+ and Ni2+ both proceed via I-D. Reaction rate constants are generally higher than those obtained by experiment but the simply constructed metal(II) ion-water potential reproduces the relative order quite well. (C) 2006 Wiley Periodicals, Inc.