ELECTROREDUCTION OF PD-2(DPPM)(2)CL-2 AND PD(DPPM)CL-2 [DPPM = BIS(DIPHENYLPHOSPHINO)METHANE] IN APROTIC MEDIUM UNDER CARBON-DIOXIDE - ELECTROGENERATION OF PD-3(MU(3)-CO)(MU-DPPM)(3)

The electroreduction of the d(9)-d(9) Pd-2(dppm)(2)Cl-2 and monomeric d(8) Pd(dppm)Cl-2 complexes in aprotic medium (such as DMF, THF and ac etonitrile) has been performed under CO2 atmosphere. In all cases the final products are CO32- anion, CO and the neutral Pd-3(mu(3)-CO)(mu-d ppm)(3) cluster. This electroreduction is not catalytic but rather sto ichiometric. The electroreduction mechanisms have been addressed exper imentally by electrochemical methods and IR spectroscopy, and theoreti cally by density functional methods via the geometry optimizations of the proposed intermediates. The intermediates ''Pd-2(dppm)(2)'' and '' Pd(dppm)'' are assumed to be active towards the binding of CO2 prior t o its reduction.