Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with azulenes

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 (1) with azulene under thermal activation afforded the novel clusters RuOs3(μ-H)(CO)9(μ3,η5:η2:η2-C10H9) (3) and Ru2Os3(μ-H)2(CO)13(μ-CO)(μ3,η5:σ2-C10H8) (5a), with 4,6,8-trimethylazulene to give RuOs3(μ-H)(CO)8(μ-CO)(μ,η5:η4-C10H6Me3) (4) and Ru2Os3(μ-H)2(CO)13(μ-CO)(μ3,η5:σ2-C10H5Me3) (5b), and with guaiazulene to give Ru2Os3(CO)11(μ3,η5:η3:η3-C10H5Me2iPr) (6), respectively. In 3–5, cluster-to-ligand hydrogen transfer appears to have taken place, with the organic moiety capping a trimetallic face in 3, bridging a metal–metal bond in 4 and via a μ3,η5:σ2 bonding mode in 5a and 5b. Cluster 6 contains a trigonal bipyramidal metal framework with the guaiazulene ligand over a triangular metal face. All five clusters have been completely characterised, including by single-crystal X-ray diffraction analysis.