Alkyne diruthenium chemistry

The reaction of [Ru2(CO)4(μ-CO)(μ-dppm)2] (1) with alkynes RCCR′ gives the alkyne complexes [Ru2(CO)4(μ-RCCR′)(μ-dppm)2] [2, R′=H; 3, R′=CO2Me or COMe; 4, R′=CCR], [Ru2(CO)4H(CCR)(μ-dppm)2] (5) or [Ru2(CO)2(μ-CO)H(μ-CCR)(μ-dppm)2] (6), when R=Ph. Complex 6 reacts with chlorinated solvent to give [Ru2(CO)2(μ-CO)Cl(μ-CCR)(μ-dppm)2] (7), R=Ph. Complex 1 reacts with excess alkyne RCCH to give [Ru2(CO)2(μ-CO){C(CH2)R}(μ-CCR)(μ-dppm)2] (8), when R=Ph, Bu or CH2CH2CCH, and, when R=Ph, 8 reacts with more PhCCH to give [Ru2(CO)2(μ-CCHPh){C(CH2)Ph}(μ-CCPh)(μ-dppm)2] (9), a complex containing three different organic ligands (alkenyl, alkynyl and vinylidene).