Supported cyclopentadienylmetal carbonyl complexes : III. Silica-gel-supported iron and cobalt derivatives

Abstract

Mononuclear cyclopentadienylcobalt carbonyl and cyclopentadienyliron carbonyl derivatives were covalently linked to a silica gel support either by reaction of (C₂H₅O)Si(CH₃)₂C₅H₅ or of (C₂H₅O)₃SiC₅H₅ with macroporous silica gel supported materials and subsequent treatment with Co₂(CO)₈ or Fe₂(CO)₉ or by reaction of (C₂H₅O)Si(CH₃)₂C₅H₄Co(CO)₂ and (C₂H₅O)₃SiC₅H₄Co(CO)₂ with a silica gel support. In contrast to their unsupported analogues, no bi- nuclear or polynuclear species are formed from the SiO₂-supported metal carbonyl derivatives even at temperatures up to 200°C. The cobalt derivative was found to be a catalyst for olefin hydroformylation reactions. Binuclear SiO₂-supported species are formed when [(C₂H₅O)Si(CH₃)₂C₅H₄Fe- (CO)₂]₂ or [(C₂H₅O)₃SiC₅H₄Fe(CO)₂]₂ are treated with a silica gel support. A large fraction of these surface-bound dimers are irreversibly converted into mononuclear hydridoiron carbonyl derivatives by hydrogen at elevated pressures.