An Electron Spin Resonance Study of the tert-Butylsulfinyl Radical

The tert-butylsulfinyl radical, (CH3)3CSO•, can be prepared directly in the cavity of an e.p.r. spectrometer by photolysis of di-tert-butyl peroxide in a solution of tert-butylsulfenic acid in toluene or isopentane at low temperatures (−40° to−100°). The e.s.r. spectrum consists of a rather broad singlet (ΔHmis ∼ 1.9 G) with the field center at g = 2.0106.This radical undergoes self-reaction by a bimolecular process and a 2.5 × 10−7 M solution has a half-life of 0.07 s at −100 °C. It is, therefore, much shorter-lived than the iso-structural tert-butylperoxy radical, (CH3)3COO•.