Exclusion of six-coordinate intermediates in the electrochemical reduction of CO2 catalyzed by [Pd(triphosphine)(CH3CN)](BF4)2 complexes

[Pd(triphosphine)(Ch₃CN)](BF₄)₂ complexes have been prepared with mesityl or trimethoxybenzene substituents on the central phosphorus atom of the triphosphine ligand. An X-ray diffraction study of [Pd(MesetpE is Bis((diethylphosphino)ethyl)mesitylphosphine has been completed. The cation has a square-planer structure with one methyl group of the central mesityl substituent blocking one potential coordination site. Kinetic studies of this complex in dimethylformamide indicate that the rate-determining step is the reaction of the [Pd-(MesetpE)(DMF)] cation with CO₂.