Protonation and acylation of the heterometallic complexes (μ-H)Os3(μ-O2CC5H4FeCp)(CO)10 and Fe{(μ-O2CC5H4)(μ-H)Os3(CO)10}2

The reactions of the heterometallic complexes (μ-H)Os₃(μ-O₂CC₅H₄FeCp)(CO)₁₀ (1) and Fe{(μ-O₂CC₅H₄)(μ-H)Os₃(CO)₁₀}₂ (2) with CF₃COOH, CF₃SO₃H, and AcCI were studied. The reaction of 1 with CF₃COOH involves interaction with the Cp ligands, protonation of the O atom of the bridging carboxylate group, and oxidative degradation of the complex. At low concentrations, CF₃SO₃H protonates the O atom of the bridging carboxylate group, while at high concentrations, degradation of the complex takes place. The reaction of complex 2 with either CF₃COOH or low concentrations of CF₃SO₃H results in successive elimination of two [(μ-H)Os₃(CO)₁₀] cluster fragments due to protonation of the O atoms of the carboxylate groups. In the case of high CF₃SO₃H concentrations, the Os-Os bonds of both cluster fragments of 2 are also protonated to give the [Fe{(μ-O₂CC₅H₄)(μ-H)₂Os₃(CO)₁₀}₂]²⁺ dication. The Friedel-Crafts acylation of 1 takes place only when a large excess of AcCl and AlCl₃ is used to give two new complexes, (μ-H)Os₃(μ-O₂CC₅H₄FeC₅H₄C(O)CH₃)(CO)₁₀ and (μ-H)Os₃(μ-O₂CC₅H₃C(O)CH₃ FeCp)(CO)₁₀ in a 2 : 1 ratio.