Quantum mechanical study on the mechanism and kinetics of the cis-to-trans isomerization of [Pd(C6Cl2F3)I(PH3)2]

In this work, mechanism and kinetics of the cis-to trans isomerization of [Pd(C6Cl2F3)I(PH3)2], has been theoretically investigated in detail. Using quantum mechanical approach, different pathways were investigated. Experimentally, a four-pathways mechanism had been proposed for cis-to-trans isomerization of [Pd(C6Cl2F3)I(PH3)2] which consists of two PPh3-sensitive (k3,k4) and two PPh3-insensitive (k1,k2). For PH3-sensitive pathways, a complex is initially formed in the shape of a square pyramidal following which a process through a trigonal bipyramidal transition state occurs. Our proposal for PH3-insensitive pathway is a dissociative reaction with a fast equilibrium step following which the slow process occurs. Considering the solvent effects, the activation energy, activation enthalpy and activation Gibbs free energy for different pathways were calculated. Using Gibbs free energies and the transition state theory, the rate constants have been evaluated. k3 Pathway (solvent-assisted) has the main contribution in this process.

Cis/trans isomerization of [Pd(C6Cl2F3)I(PH3)2] complex has been investigated theoretically. A mechanism had been proposed which consists of ligand sensitive (k3,k4) and ligand insensitive (k1,k2) pathways. Our proposal for the later is a dissociative reaction. Using calculated Gibbs free energies and the transition state theory, the rate constants have been evaluated.Figure optionsDownload as PowerPoint slideHighlights
► We investigate the mechanism and kinetics of the cis-to-trans isomerization of [Pd(C6Cl2F3)I(PH3)2].
► Ligand sensitive pathway (solvent-assisted) has the main contribution in this process.
► The calculated parameters are in good agreement with the experimental values.