Reversible thermal carbon-hydrogen bond cleavage in alkanes and arenes with dihalogenobis(triphenylphosphine)palladium(II) complexes

Abstract

Dihalogenobis(triphenylphosphine)palladium(II) complexes 1, PdX 2(PPh3)2 (X = Cl, Br, I), reacts reversibly with saturated and aromatic hydrocarbons RH (RH = p-xylene, toluene, benzene, n-hexane, cyclohexane), slowly at ambient temperature and rapidly on heating at 70-130°C, to produce hydridodihalogeno(organo)bis(triphenylphosphine)- palladium(IV) complexes 2, Pd(H)(R)X2(PPh3)2; in the presence of bases complexes 2 eliminate hydrogen halide forming organobis(triphenylphosphine)palladium(II) halide 3, Pd(R)X(PPh 3)2.