Nature of the activation of a Pd(acac)2PPh3 and NaH2PO2-based metal complex catalyst for hydrogenation

The role of hydrogen and unsaturated substrates in the activation of a metal complex hydrogenation catalyst based on Pd(acac) 2 PPh 3 and NaH 2 PO 2 was considered. Deeper dephenylation of organophosphorus ligands of the palladium complex catalyst in the course of hydrogenation of unsaturated derivatives was found to be the principal cause of activation. The role of unsaturated substrates is limited to stabilization of catalytically active palladium complexes formed by dephenylation.