Reactions of a diruthenium complex with sulfur, selenium and sulfur dioxide

Reaction of the complex [Ru-2(CO)(4)(mu-CO)(mu-dppm)(2)] 1 (dppm = Ph2PCH2PPh2) with sulfur or selenium gave the corresponding [Ru-2(Co)(4)(mu-E)(mu-dppm)(2)] (E = 2 or 3) in high yield. Both 2 and 3 reacted with an excess of sulfur to give the disulfido, mu-sulfido complex [Ru-2(CO)(2)(mu-CO)(mu-S)(S-2)(mu-dppm)(2)] 4. Complex 1 reacted readily with SO2 to give [Ru-2(CO)(4)(mu-SO2)(mu-dppm)(2)] 5, containing a bridging S-bonded SO2 ligand. The complexes 1, 4 and 5 have been characterized by crystal structure determinations and are shown to contain Ru-Ru single bonds.