Highly Stable Silyl Radicals (EtnMe3-nSi)3Si• (n = 1−3)

Silyl radicals (EtnMe3-nSi)3Si• (1, n = 1; 2, n = 2; 3, n = 3) were generated by hydrogen abstraction from (EtnMe3-nSi)3SiH (4, n = 1; 5, n = 2; 6, n = 3) with di-tert-butyl peroxide and by photolysis of (EtnMe3-nSi)4Si (7, n = 1; 8, n = 2; 9, n = 3) and (EtnMe3-nSi)3SiSi(SiMe3-nEtn)3 (10, n = 1; 11, n = 2; 12, n = 3) and observed by ESR spectroscopy. These silyl radicals are considerably stable at room temperature; the half-lives of 1, 2, and 3 generated from 10−12 are 3 h, 1 day, and 1.5 months at 15 °C, respectively.