σ-Silane, Disilanyl, and [W(μ-H)Si(μ-H)W] Bridging Silylene Complexes via the Reactions of W(PMe3)4(η2-CH2PMe2)H with Phenylsilanes

W(PMe3)(4)(eta(2)-CH2PMe2)H reacts with PhSiH3 to give the first examples of diphenyldisilanyl compounds, W(PMe3)(4)(SiH2SiHPh2)H-3 and W(PMe3)(3)(SiH2Ph)(SiH2SiHPh2)H-4, via a mechanism that is proposed to involve migration of a SiHPh2 group to a silylene ligand. In addition to the formation of the aforementioned mononuclear compounds, the reaction of W(PMe3)(4)(eta(2)-CH2PMe2)H with PhSiH3 also yields a novel dinuclear compound, [W(PMe3)(2)(SiHPh2)H-2](mu-Si,P-SiHPhCH2PMe2)(mu-SiH2)[W(PMe3)(3)H-2], which features a bridging silylene ligand that participates in 3-center-2-electron interactions with both tungsten centers. The bonding within the [W(mu-H)Si(mu-H)W] core can be described by a variety of resonance structures, some of which possess multiple bond character between tungsten and silicon. In this regard, [W(PMe3)(2)(SiHPh2)H-2](mu-Si,P-SiHPhCH2PMe2)(mu-SiH2)[W(PMe3)(3)H-2] possesses the shortest WSi bond length reported. The corresponding reaction of W(PMe3)(4)(eta(2)-CH2PMe2)H with Ph2SiH2 yields the s-silane compound, W(PMe3)(3)(s-HSiHPh2)H-4.