Reaction of [Os₃H₂(CO)₁₀] with the diyne Me₃SiC₂C₂SiMe₃ and the reactivity of the products towards [Co₂(CO)₈]: The X-ray structures of [Os₃(μ-H)(CO)₁₀ {μ-η¹-η²-HC₂ (SiMe₃)C₂(SiMe₃)}],[Os₃

The reaction of [Os₃H₂(CO)₁₀] with Me₃SiC₂C₂SiMe₃ affords both [Os₃(μ-H) (CO)₁₀{μ-η¹-η²-HC ₂(SiMe₃)C₂(SiMe₃)}] (1) and [Os₃(μ-CO)(CO)₉(μ₃-η ²-Me₃SiC₂C₂SiMe₃)] (2) in good yield, 2 being favoured with an excess of diyne. In 1, one edge of the triosmium unit is bridged by the vinyl moiety of a transformed bis(trimethylsilyl)-1,4-butadiyne ligand that has undergone a hydride transfer and a 1,2-trimethylsilyl shift. Compound 2 is selectively desilylated in methanol to produce a single isomer of the known cluster [Os₃(μ-CO)(CO)₉{μ₃-η ²-HC₂C₂SiMe₃}] (3). Whereas reaction of 3 with [Co₂(CO)₈] results in the production of the previously reported cluster [Os₃{μ₃-η²-:μ-η ²-(Me₃SiC₂C₂H)[Co ₂(CO)₆]}(μ-CO)(CO)₉] (4) and a second product [Os₃(μ-H)(CO)₉{μ₃-η ¹:η²-;μ-η²-Me₃SiC ₂C₂[Co₂(CO)₆]}] (5), the reaction of 1 and 2 results in recovery of the starting material or transfer of the alkyne ligand to the Co₂ unit. Compound 4 undergoes a transformation to 5 in visible light. All the cluster complexes have been characterized spectroscopically, and the solid-state structures of 1, 2 and 5 have been determined by single-crystal X-ray diffraction.