Investigation of the reaction of Pd(acac)/sub 2/ x PPh/sub 3/ with molecular hydrogen

The reactions of Pd(acac)/sub 2/ x PPh/sub 3/ with hydrogen in dichloroethane at 80/sup 0/C have been studied. It has been discovered that the reduction of Pd(acac)/sub 2/ x PPh/sub 3/ is accompanied by the liberation of 2 moles of acetylacetone and 1 mole of benzene and the formation of palladium complexes with phosphorus-containing ligands. It has been established that the original complex Pd(acac)/sub 2/ x PPh/sub 3/ also interacts with the solvent (dichloroethane) to form the complexes PdCl(acac) x PPh/sub 3/ and PdCl/sub 2/Cl/sub 2/(PPh/sub 3/)/sub 2/ and the trinuclear cluster (Pd/sub 3/(PPh/sub 3/)/sub 3/-(PPh/sub 2/)/sub 2/Cl)/sup +/ x Cl/sup -/. The structure of the intermediates has been established by NMR and IR spectroscopy and by gas-liquid chromatography. A scheme of the interactions between the components of the catalytic system has been proposed on the basis of the data obtained.