Details

Autor(en) / Beteiligte

• Zaborovskiy, Andriy B.
• Lutsyk, Daria S.
• Prystansky, Ruslan E.
• Kopylets, Vladimir I.
• Timokhin, Vitaliy I.
• Chatgilialoglu, Chryssostomos

Titel

A mechanistic investigation of (Me 3Si) 3SiH oxidation

Ist Teil von

• Journal of organometallic chemistry, 2004-09, Vol.689 (18), p.2912-2919

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2004

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• O 2 abstracts hydrogen from (Me 3Si) 3SiH spontaneously, initiating a radical chain oxidation of this silane. The resulting silyl radical adds to oxygen to form a peroxyl radical that undergoes three consecutive unimolecular steps. Evidence is provided that the rate determining step is the formation of a dioxirane-like pentacoordinated silyl radical. The interaction of (Me 3Si) 3SiH with O 2 is known to afford (Me 3SiO) 2Si(H)SiMe 3 in which the two oxygen atoms arise from the same oxygen molecule. In order to investigate the mechanism of this unusual reaction, the oxidation rates were measured in the temperature range 30–70 °C by following oxygen uptake in the presence and absence of hydroquinone as inhibitor. The rate constant for the spontaneous reaction of (Me 3Si) 3SiH with O 2 was determined at 70 °C to be ∼3.5 × 10 −5 M −1 s −1. A sequence of the propagation steps is proposed by combining the previous and present experimental findings with some theoretical results obtained at the semiempirical level. These calculations showed that the silylperoxyl radical (Me 3Si) 3SiOO undergoes three consecutive unimolecular steps to give (Me 3SiO) 2Si( )SiMe 3. Evidence has been obtained that the rate determining step is the rearrangement of silylperoxyl radical to a dioxirand-like pentacoordinated silyl radical. Our findings are of considerable importance for the understanding of the oxidation of hydrogen-terminated silicon surfaces.