The differing modes of reaction of 1-(8-dimethylamino-1-naphthyl)-1-hydrodisilane and 1-(1-naphthyl)-1-hydrodisilane in nickel-catalyzed reactions with acetylene: Formation of a pseudo-pentacoordinate silole via Si-Si bond cleavage vs hydrosilation without Si-Si bond cleavage

Pseudo-pentacoordinate 1-(8-dimethylamino-1-naphthyl)-1-hydrodisilanes 1 and 2 and the tetracoordinate counterpart 3 have been prepared. In the presence of an Ni(0) complex as catalyst, 1 and 2 undergo degradation to generate a silylene species and a hydrosilane. The complex with Ni of the silylene species from 1 has been trapped with an excess of diphenylacetylene to give a pseudo-pentacoordinate silole 4. The X-ray structure of 4 indicates that this silole occupies two pseudo-equatorial positions. In contrast, the tetracoordinate hydrodisilane 3 undergoes hydrosilation without Si-Si bond cleavage.