Synthesis and Reactivity of N-Heterocyclic Silylene Stabilized Disilicon(0) Complexes.

Synthesis and reactivity of disilicon(0) complexes are of fundamental and application importance. Herein, we report the development of an N-heterocyclic imino-substituted silylene (1), which has strong σ-donating ability and is significantly sterically hindered. The one-pot reaction of this silylene with [IPr→SiCl 2 ] (IPr=1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene) and KC 8 (2 equiv) in THF at -30 °C leads to a silylene-ligated disilicon(0) complex (2), isolated as red crystals in 60 % yield. Characterization data and DFT calculations show that the trans-bent Si 4 skeleton in 2 features a Si 0 =Si 0 double bond with significant π-π bonding and one lone pair of electrons on each of these two Si 0 atoms. Complex 2 reacts readily with phenylacetylene, producing a structurally intriguing silatricyclic complex 6,8-diaza-1,2,5-trisilatricyclo-[3.2.1.0 2,7 ]-oct-3-ene (3), and revealing new aspects of low-valent silicon chemistry.