Oxidative addition of 1,3-diynes at triosmium clusters with cleavage of the central carbon–carbon bond: X-ray crystal structure of [Os3(µ3,η2-C2Ph)(µ-C2Ph)(CO)9] derived from 1,4-diphenylbuta-1,3-diyne

The diyne clusters [Os3(µ3,η2-RCCCCR)(CO)10](R = Me, Et, Ph, But, SiMe3) in hydrocarbon solvent at 120 °C decarbonylate to give the nonacarbonyl clusters [Os3(µ3,η2-C2R)(µ-C2R)(CO)9] when R = Ph, But, or SiMe3, [Os3H(µ3,σ,η2,η2-EtCC–CCCHMe)(CO)9] when R = Et, and [Os3(C4Me2)(CO)9] of known structure when R = Me; the µ-C2Ph ligand in [Os3(µ3, η2-C2Ph)(µ-C2Ph)(CO)9](X-ray structure) is unusual in bridging unsymmetrically through only one carbon atom.