A Monte Carlo simulation study of solvent effect on Eu 3+ to Nd 3+ ion mutation

Abstract

The solvent effects on the relative free energies of solvation of Eu 3+ to Nd 3+ ion mutation have been investigated using a Monte Carlo simulation of statistical perturbation theory. Comparing the relative free energies of Eu 3+ to Nd 3+ ion mutation, in H 2O (TIP4P) in this study with those of the published works, that in H 2O (TIP4P) is −19.11±0.36 kcal/mol in this study, that of the published work in H 2O (TIP3P) is −23.6 kcal/mol and that of experimental work is −19.2 kcal/mol, respectively. There is good agreement among the three studies, considering both methods of obtaining hydration free energies and the standard deviations. For the present Eu 3+ and Nd 3+ ions, the relative free energies of solvation vs. Born's function of bulk solvents decrease with increasing Born's function of bulk solvents except for CH 3OH, THF and MeOMe. The strong ion–solvent interactions in CH 3OH, THF and MeOMe solutions could be due to the electron pair donor properties of the solvents to ion, i.e., Donor number of CH 3OH, THF and MeOMe established by Gutmann. There is also good agreement between the calculated structural properties in this study and the published works obtained by computer simulations and experiments.