Oxidative Addition of Water to Ir(I) Complexes Bearing a Pincer-Type Silyl Ligand.

Reaction of water with in situ generated [(PSiP-R)Ir I ] (PSiP-R = [{2-(R 2 P)C 6 H 4 } 2 MeSi] - ; R = cyclohexyl, t Bu or i Pr) from [(PSiP-R)Ir(H) 4 ] and tert -butylethylene (tbe) showed high ligand dependency. Oxidative addition of water cleanly proceeded in the reaction of [(PSiP- t Bu)Ir I ] in THF at room temperature to selectively afford a 16-electron hydrido-hydroxo complex [(PSiP- t Bu)Ir(H)(OH)] almost quantitatively. In contrast, the reaction of cyclohexyl and i Pr derivatives was unselective and formed various products containing Ir-H bonds. In the case of i Pr-derivative, a small amount of 18-electron hydrido-hydroxo aqua complex [(PSiP- i Pr)Ir(H)(OH)(H 2 O)] was isolated and structurally characterized by X-ray crystallography.