The chemistry of polynuclear compounds. Part XXV. Some reactions of α-tetrahydridododecacarbonyltetraruthenium with cyclic olefins

Abstract

The complexes H₂Ru₃(CO)₉C₈H₁₂, HRu₃(CO)₉C₈H₁₁, Ru₄(CO)₁₁C₈H₁₀, Ru₄(CO)₁₂C₈H₁₀, and Ru₄(CO)₁₂C₈H₁₂ have been identified as the products of the reaction of α-H₄Ru₄(CO)₁₂ with either cyclo-octa-1,5-diene or cyclo-octa-1,3-diene. The complexes are also formed by reaction of α-H₂Ru₄(CO)₁₃ with cyclo-octa-1,5-diene, and the complexes H₂M₃(CO)₉C₈H₁₂(M = Ru or Os) are obtained by reaction of M₃(CO)₁₂ with cyclo-octene. Structures of the complexes are discussed, where possible, in terms of spectroscopic data and in the case of Ru₄CO₁₁C₈H₁₀ on the basis of single crystal X-ray analysis. ¹H N.m.r. studies of H₂Ru₃(CO)₉C₈H₁₂ indicate that the molecule undergoes two distinct types of fluxional behaviour involving in the first instance the C₈H₁₂ ligand, and in the second the two hydrido-ligands. ΔG^‡ Values for these processes (and for the corresponding osmium complex) have been determined. HRu₃CO₉C₈H₁₁ reacts with hydrogen gas to give (H₂Ru₃CO)₉C₈H₁₂. The complexes Ru₄(CO)₁₁C₈H₁₀ and Ru₄(CO)₁₂C₈H₁₂ react with hydrogen to give H₂Ru₃(CO)₉C₈H₁₂ and α-H₄Ru₄(CO)₁₂, and Ru₄(CO)₁₂C₈H₁₀ forms α-H₄Ru₄(CO)₁₂ only. )α-H₄Ru₄(CO)₁₂ is converted into α-H₂Ru₄(CO)₁₃ in ca. 30% yield by reaction with cycloheptene. The compounds Ru₄(CO)₁₂C₈H₁₀, Ru₄(CO)₁₂C₈H₁₂, HRu₃-(CO)₉C₈H₁₁, and H₂Ru₃(CO)₉C₈H₁₀ have been obtained from the reaction of Ru₃(CO)₁₂ with cyclo-octa-1,3-diene.