Multiple cluster CH activations and transformations of furan by triosmium carbonyl complexes

Abstract

Reaction of Os₃(CO)₁₀(NCMe)₂ with the triosmium furyne complex Os₃(CO)₉(μ₃,η²-C₄H₂O)(μ-H)₂, 1 yielded the bis-triosmium complex 2 containing a bridging furyenyl ligand by CH activation at the uncoordinated C–C double bond. Heating 2 led to additional CH activation with formation of the first furdiyne C₄O ligand in the complex Os₃(CO)₉(μ-H)₂(μ₃-η²-2,3-μ₃-η²-4,5-C₄O)Os₃(CO)₉(μ-H)₂, 3. The furdiyne ligand in 3 was subsequently ring-opened and decarbonylated to yield products 4 and 5 containing novel bridging C₃ ligands. Complex 2 also undergoes ring opening to yield an intermediate Os₃(CO)₉(μ-H)(μ₃-η²-μ-η²-CH–C–CH–CO)Os₃(CO)₁₀(μ-H), 6 which was also decarbonylated thermally to yield 4 and 5. All products were characterized by a combination of IR, NMR, mass spec and single-crystal X-ray diffraction analyses.