Cobalt-Assisted Silicon−Silicon Bond Activation

A number of oligosilylalkynes were converted to the respective dicobalt hexacarbonyl complexes. These compounds were found to be surprisingly reactive, indicating Si−Si bond activation in the coordination sphere of the cobalt atoms. The presence of more than one silicon−silicon bond restricted clean conversions, and therefore the pentamethyldisilanylphenylacetylene complex was prepared, which engaged in defined reactions. The rearrangement of an oligosilylalkyne dicobalt hexacarbonyl complex to a dicobalt hexacarbonyl bis(dialkylsilylene) complex was observed. The reaction of tris(trimethylsilyl)silane with dicobalt octacarbonyl yielded the product of formal replacement of two carbonyl ligands with dimethylsilylene groups.