A Density Functional Study of SN2 Substitution at Square-planar Pt(II) Complexes

Jason Cooper and Tom Ziegler

Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
 

Density functional theory has been used to study the reaction path and energetics of the classic SN2 substitution at a square-planar metal center.

Enthalpies and entropies in the gas phase and in aqueous solution have been calculated and compared to experimental values where these are available.  In contrast to a number of previous theoretical studies, deviation of the transition state from the expected trigonal bipyramidal configuration has been permitted within our model.  A distorted trigonal bipyramidal configuration has been found to be appropriate nevertheless, and the influence of the entering group, leaving group, and the trans and cis ligands on both reaction kinetics and transition state geometry has been discussed.