title: Isolable photoreactive polysilyl radicals.
abstract: Reaction of silyl substituted dichlorosilanes with lithiosilanes in hexane leads exclusively to the corresponding stable silyl radicals. Two radicals, the new (t-Bu(2)MeSi)(2)HSi(t-Bu(2)MeSi)(2)Si* (1) and the previously isolated (t-Bu(2)MeSi)(3)Si* (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 lambda > 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.
authors.affiliation: Schulich Faculty of Chemistry and the Lise Meitner Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Gregory
authors.initials: G
authors.lastname: Molev
authors.forename: Boris
authors.initials: B
authors.lastname: Tumanskii
authors.forename: Dennis
authors.initials: D
authors.lastname: Sheberla
authors.forename: Mark
authors.initials: M
authors.lastname: Botoshansky
authors.forename: Dmitry
authors.initials: D
authors.lastname: Bravo-Zhivotovskii
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Apeloig