Mechanism of the solvent effect on the rate of the cyclohexene hydroxymethoxycarbonylation catalyzed by bis(triphenylphosphine)palladium

Kinetic data of the cyclohexene hydroxymethoxycarbonylation catalyzed by bis(triphenylphosphine) palladium Pd(PPh 3 ) 2 were processed and considered on the basis of the quantum-chemical calculations. By the method of density functional DFT PBE/3z we found that among the possible catalyst moleculs based on the tetrakis(triphenylphosphine)palladium the most stable is Pd(PPh 3 ) 2 with the coordination number of palladium equal 2. The interaction energy of Pd(PPh 3 ) 2 with acetone, acetonitrile, dichloroethane, 1,4-dioxane, nitromethane, and tetrahydrofuran calculated by PM3 method was found to correlate linearly with the reaction rate logarithm. The mechanism of the solvent effect on the reaction rate consists in a specific complexation with the catalyst depending on the molecule rigidity and the creation of energetic and steric constraints for the substrate to access the catalyst.