One- and Two-Electron Transfer Oxidation of 1,4-Disilabenzene with Formation of Stable Radical Cations and Dications.

Abstract

Electron‐transferable oxidants such as B(C6F5)3/nBuLi, B(C6F5)3/LiB(C6F5)4, B(C6F5)3/LiHBEt3, Al(C6F5)3/(o‐RC6H4)AlH2 (R=N(CMe2CH2)2CH2), B(C6F5)3/AlEt3, Al(C6F5)3, Al(C6F5)3/nBuLi, Al(C6F5)3/AlMe3, (CuC6F5)4, and Ag2SO4, respectively were employed for reactions with (L)2Si2C4(SiMe3)2(C2SiMe3)2 (L=PhC(NtBu)2, 1). The stable radical cation [1]+. was formed and paired with the anions [nBuB(C6F5)3]− (in 2), [B(C6F5)4]− (in 3), [HB(C6F5)3]− (in 4), [EtB(C6F5)3]− (in 5), {[(C6F5)3Al]2(μ‐F)]− (in 6), [nBuAl(C6F5)3]− (in 7), and [Cu(C6F5)2]− (in 8), respectively. The stable dication [1]2+ was also generated with the anions [EtB(C6F5)3]− (9) and [MeAl(C6F5)3]− (10), respectively. In addition, the neutral compound [(L)2Si2C4(SiMe3)2(C2SiMe3)2][μ‐O2S(O)2] (11) was obtained. Compounds 2–11 are characterized by UV‐vis absorption spectroscopy, X‐ray crystallography, and elemental analysis. Compounds 2–8 are analyzed by EPR spectroscopy and compounds 9–11 by NMR spectroscopy. The structure features are discussed on the central Si2C4‐rings of 1, [1]+., [1]2+, and 11, respectively.