title: Solvent effect on the potential energy surfaces for the one-electron reduction of CF3X (X = Cl, Br, I) molecules: a DFT PCM study.
abstract: In this article, an effect of solvent on potential energy surfaces, constructed at the PBE1PBE/aug-cc-pVTZ level vs C-X distances for the neutral molecules CF(3)X (X = Cl, Br, I) and the corresponding radical anions CF(3)X¯, is studied using the polarizable continuum model (PCM). The properties and energy changes in these compounds in the presence of argon, acetonitrile (ACN), and dimethyl sulfoxide (DMSO) are compared to the results obtained earlier in vacuo. The presence of solvent very weakly influences the neutral molecules, but it significantly changes properties of radical anions, such as structural parameters and partial charges on atoms. The effect of solvent is manifested also in strong modification of the potential energy surfaces, on which the minima corresponding to the locally stabilized forms of CF(3)X¯ are shallower in argon, and in ACN and DMSO, they almost disappear. This in turn results in much higher energy barriers (by about 0.2-0.3 eV) for the reductive cleavage of C-X bonds in polar solvents than in vacuo. Despite different dielectric constants of ACN and DMSO, the potential energy surfaces obtained in these two solvents are very similar, and the activation energies equal, respectively, 0.635 and 0.637 eV for CF(3)Cl; 0.479 and 0.481 eV for CF(3)Br; and 0.336 and 0.337 eV for CF(3)I.
authors.affiliation: Department of Theoretical and Structural Chemistry, University of Lodz, ul. Pomorska 163/165, 90-236 Łódź, Poland. anignacz@uni.lodz.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Ignaczak