Synthesis, structure, and metathesis activity of ruthenium carbene complexes containing diphosphines

A series of ruthenium benzylidene complexes containing diphosphines (xantphos, dppf, Cy2P(CH2)nPCy2 (n=5, 8)) has been prepared, either by phosphine exchange in the ruthenium carbene complex RuCl2(CHPh)(PPh3)2, or in a one-pot two-steps synthesis from RuCl2(PPh3)3, phenyldiazomethane, and diphosphine. The complexes have been characterised spectroscopically (NMR, IR, MS) and by X-ray structural analysis. Their catalytic activity in olefin metathesis is also discussed.