σ‑Silane, Disilanyl, and [W(μ‑H)Si(μ‑H)W] Bridging Silylene Complexes <i>via</i> the Reactions of W(PMe<sub>3</sub>)<sub>4</sub>(η<sup>2</sup>‑CH<sub>2</sub>PMe<sub>2</sub>)H with Phenylsilanes
dataset
posted on 2014-12-31, 00:00 authored by Ashley
A. Zuzek, Michelle C. Neary, Gerard ParkinW(PMe<sub>3</sub>)<sub>4</sub>(η<sup>2</sup>-CH<sub>2</sub>PMe<sub>2</sub>)H reacts with PhSiH<sub>3</sub> to give the first
examples of diphenyldisilanyl compounds, W(PMe<sub>3</sub>)<sub>4</sub>(SiH<sub>2</sub>SiHPh<sub>2</sub>)H<sub>3</sub> and
W(PMe<sub>3</sub>)<sub>3</sub>(SiH<sub>2</sub>Ph)(SiH<sub>2</sub>SiHPh<sub>2</sub>)H<sub>4</sub>, <i>via</i> a mechanism
that is proposed to involve migration of a SiHPh<sub>2</sub> group
to a silylene ligand. In addition to the formation of the aforementioned
mononuclear compounds, the reaction of W(PMe<sub>3</sub>)<sub>4</sub>(η<sup>2</sup>-CH<sub>2</sub>PMe<sub>2</sub>)H
with PhSiH<sub>3</sub> also yields a novel dinuclear compound, [W(PMe<sub>3</sub>)<sub>2</sub>(SiHPh<sub>2</sub>)H<sub>2</sub>](μ‑<i>Si,P</i>-SiHPhCH<sub>2</sub>PMe<sub>2</sub>)(μ‑SiH<sub>2</sub>)[W(PMe<sub>3</sub>)<sub>3</sub>H<sub>2</sub>], which
features a bridging silylene ligand that participates in 3-center-2-electron
interactions with both tungsten centers. The bonding within the [W(μ‑H)Si(μ‑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(PMe<sub>3</sub>)<sub>2</sub>(SiHPh<sub>2</sub>)H<sub>2</sub>](μ‑<i>Si,P</i>-SiHPhCH<sub>2</sub>PMe<sub>2</sub>)(μ‑SiH<sub>2</sub>)[W(PMe<sub>3</sub>)<sub>3</sub>H<sub>2</sub>] possesses the shortest W–Si
bond length reported. The corresponding reaction of W(PMe<sub>3</sub>)<sub>4</sub>(η<sup>2</sup>-CH<sub>2</sub>PMe<sub>2</sub>)H with Ph<sub>2</sub>SiH<sub>2</sub> yields the σ-silane compound,
W(PMe<sub>3</sub>)<sub>3</sub>(σ-HSiHPh<sub>2</sub>)H<sub>4</sub>.
