Isolable Photoreactive Polysilyl Radicals

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• 作者：Gregory Molev ; Boris Tumanskii ; Dennis Sheberla ; Mark Botoshansky ; Dmitry Bravo-Zhivotovskii ; Yitzhak Apeloig
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：August 26, 2009
• 年：2009
• 卷：131
• 期：33
• 页码：11698-11700
• 全文大小：204K
• 年卷期：v.131,no.33(August 26, 2009)
• ISSN：1520-5126

文摘

Reaction of silyl substituted dichlorosilanes with lithiosilanes in hexane leads exclusively to the corresponding stable silyl radicals. Two radicals, the new (t-Bu₂MeSi)₂HSi(t-Bu₂MeSi)₂Si• (1) and the previously isolated (t-Bu₂MeSi)₃Si• (2), were isolated and fully characterized including by X-ray crystallography. This one-step method is general and was applied for the synthesis of other silyl radicals. Upon irradiation radical 1 (yellow solution in hexane) decays to yield the corresponding disproportionation products, silane and disilene (blue colored). In contrast, radical 2 is photostable in the absence of additives, but it abstracts hydrogen from triethylsilane and 2-propanol upon irradiation. DFT calculations and irradiation experiments with λ > 400 nm suggest that SOMO-1 → SOMO excitation, which provides better electron accepting properties to the radical, is responsible for the photoreactivity of 1 and 2.