FACILITATED ALKALI ION TRANSFER AT THE WATER 1,2-DICHLOROETHANE INTERPHASE - AB-INITIO CALCULATIONS CONCERNING ALKALINE METAL CATION-1,10-PHENANTHROLINE COMPLEXES/

A series of calculations on the energetics of complexation of alkaline metal cations with 1,10-phenanthroline are presented. It is an experi mental fact that the ordering of the Gibbs energy of transfer across t he water/1,2-dichloroethane interphase is governed by the charge/size ratio of the different cations; the larger cations showing the lower G ibbs energy of transfer. This ordering of the Gibbs energies of transf er is reverted in the presence of 1,10-phenanthroline in the organic p hase. We have devised a thermodynamic cycle for the transfer process a nd, by means of ab initio calculations, have drawn the conclusion that in the presence of phenanthroline the Gibbs energy of transfer is gov erned by the stability of the phenanthroline/M+ complex, which explain s the observed tendency from a theoretical point of view. (C) 1998 Els evier Science S.A. All rights reserved.