An unusual carbon–carbon σ-bond cleavage reaction on attempted methylation of the anionic alkene cluster [Os3H(µ-CO){CF3(H)CC(H)CF3}(CO)9]–; X-ray crystal structure of [OS3H(µ3-σ:η2-CCCF3)(CO)9]

Abstract

Attempted methylation of the anionic fluoroalkene cluster [Os₃H(µ-CO){CF₃(H)CC(H)CF₃}(CO)₉]^–(1) with [Me₃O][BF₄] at room temperature gives four neutral products, [Os₃H{µ₃-η²-CF₃CC(H)CF₃}-(CO)₁₀](2), [Os₃H(µ₃-σ:η²-CCCF₃)(CO)₉](4), [Os₃H₂{µ₃-η₂-CF₃CCCF₃}(CO)₉](5), and an uncharacterised complex (6). The formation of (4), a major product of the reaction, necessitates the cleavage of a carbon-carbon σ-bond and an X-ray analysis of (4), confirming its structure, is presented. Crystals of (4) are triclinic, space group P, with a= 14.354(2), b= 9.510(1), c= 6.714(1)Å, α= 103.21 (2), β= 93.81 (2), γ= 90.66(2)°, and Z= 2.2 645 Unique observed data [F 6 σ(F_o), 3 ⩽θ⩽25°] refined to an R value of 0.028.