Theoretical Study of Solvent Effects on the Cis-to-Trans Isomerization of [Pd(C6Cl2F3)I(PH3)2

Abstract

In this work, the effect of different solvents on the mechanism of the cis-to-trans isomerization of [Pd(C6Cl2F3)(I)(PH3)2] has been investigated theoretically in detail. Using a quantum mechanical approach, different pathways were investigated. A three-pathway mechanism has already been proposed which consists of two PH3-sensitive steps (k 3, k 4) and one PH3-insensitive (k diss) step. Since in the k 3 pathway the solvent has two types of explicit and implicit effects, this path was investigated for both the gas phase and solvent systems (using the PCM model). In this path, solvents with larger donor numbers (necessary condition) and smaller dielectric constant and dipole moment values (sufficient condition) are more appropriate. In the k 4 pathway, the solvent has an implicit effect only, and the smaller are the dielectric constant and dipole moment of a solvent, the more appropriate it is. To find the best solvent, a parameter, called the average activation energy, was defined, which considers the contribution of each path in the mechanism.