Barium Siloxides and Catalysed Formation of Si-O-Si' Motifs.

The first unsupported barium siloxide, the homoleptic dimer [Ba {μ -OSi(SiMe ) } {OSi(SiMe ) }], is presented, and its structural features are discussed in the light of DFT computations. This complex, together with the related [Ba{μ -OSi(SiMe ) }{N(SiMe ) }] and their parent [Ba{N(SiMe ) } ] , mediates the formation of asymmetric siloxanes R Si-O-SiR' through the first case of main group metal-mediated dehydrocoupling of silanols and hydrosilanes. Early kinetic analysis highlights an unusual catalytic manifold.