Reactions of the Triosmium−Antimony Cluster Os₃(μ-SbPh₂)(μ-H)(μ₃,η²-C₆H₄)(CO)₉ with Alkynes:  C−C Bond Coupling to a Cluster-Bound Phenylene and Catalytic Alkyne Cyclotrimerization

The reaction of the osmium−antimony cluster Os3(μ-SbPh2)(μ-H)(μ3,η2-C6H4)(CO)9, 1, with the terminal alkynes PhC⋮CH and tBuC⋮CH led to products involving C−C bond coupling with the phenylene ligand on the cluster, viz., Os3(μ-SbPh2)(μ,η2-HCC(H)Ph)(μ-η4-C6H4C(H)CPh)(CO)7, 2, and Os5(μ4-Sb)(μ-SbPh2)(μ-H)(μ3,η3-C6H4)(μ,η2-PhCC(H)But)(CO)14, 4. Cluster 1 was also found to be an effective catalyst for the cyclotrimerization of diphenylacetylene to hexaphenylbenzene.