A Monte Carlo simulation study of solvent effect on Eu3+ to Nd3+ ion mutation Original Research Article

The solvent effects on the relative free energies of solvation of Eu3+ to Nd3+ ion mutation have been investigated using a Monte Carlo simulation of statistical perturbation theory. Comparing the relative free energies of Eu3+ to Nd3+ ion mutation, in H2O (TIP4P) in this study with those of the published works, that in H2O (TIP4P) is −19.11±0.36 kcal/mol in this study, that of the published work in H2O (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 Eu3+ and Nd3+ ions, the relative free energies of solvation vs. Bornʹs function of bulk solvents decrease with increasing Bornʹs function of bulk solvents except for CH3OH, THF and MeOMe. The strong ion–solvent interactions in CH3OH, THF and MeOMe solutions could be due to the electron pair donor properties of the solvents to ion, i.e., Donor number of CH3OH, 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.