Synthesis and structure of sulfur and selenium capped dihydride triruthenium clusters [Ru3(CO)7(μ-H)2(μ-dppm)(μ3-E)] (E = S, Se)

The synthesis, molecular structures and dynamic behavior of the dihydride triruthenium clusters [Ru3(CO)7(μ-H)2(μ-dppm)(μ3-S)] (2) and [Ru3(CO)7(μ-H)2(μ-dppm)(μ3-Se)] (5) are described. Both 2 and 5 are fluxional at room temperature being attributed to hydride migration between the non-bridged edges. Protonation of 2 with HBF4 affords the cationic trihydride [Ru3(CO)7(μ-H)3(μ-dppm)(μ3-S)][BF4] (6) in which the hydrides are non-fluxional due to the blocking of the free ruthenium-ruthenium edge.