QSPR analysis of solvent effect on selectivity of 18-crown-6 between Nd3+ and Eu3+ ions: A Monte Carlo simulation study

COMP 159

Hag Sung Kim, hskim@mail.uc.ac.kr, Department of Environmental &Living Chemistry, Ulsan College, San 29 Muger-dong Nam-gu, Ulsan, 680-749, South Korea
We have investigated the solvent effects on Δlog Ks (the difference of stability constant of binding) and the different free energies of binding of Nd3+ and Eu3+ ions to 18-crown-6, i.e., the selectivity of Nd3+ and Eu3+ ions to 18-crown-6 using a Monte Carlo simulation of statistical perturbation theory (SPT) in diverse solvents. The stability constant (Δlog Ks) of binding of Nd3+ and Eu3+ ions to 18-crown-6, in CH3OH was calculated in this study as -1.06 agrees well with the different experimental results of -0.44 ~ -0.6, respectively. We have reported here the quantitative solvent-polarity relationships (QSPR) studied on the solvent effects the relative free energies of binding of Nd3+ and Eu3+ ions to 18-crown-6. From the calculated coefficients of QSPR, we have noted that DN dominates the differences in relative solvation Gibbs free energies of Nd3+ and Eu3+ ions and DN dominates the negative values in differences in the stability constant (Δlog Ks) as well as the relative free energies of binding of Nd3+ and Eu3+ ions to 18-crown-6 but π* dominates the positive values in differences in the stability constant (Δlog Ks) as well as the relative free energies of binding of Nd3+ and Eu3+ ions to 18-crown-6.