Photoactivated formation of hydrogen spin adduct from phenylsilane. A new example of inverted spin trapping?

Photodissociation of phenylsilane was studied by EPR spectroscopy using N-b enzylidene-tert-butylamine N-oxide (PBN) and bis(benzene)chromium (BBC) as spin trapping systems. Under controlled UV irradiation and in the presence of dioxygen, hydrogen spin adducts were detected. Conditions for the format ion and stability of the adducts have been studied. A mechanism involving " inverted spin trapping" was propounded that implies photoactivation of the spin traps followed by the formation of the superoxide radical ion O-2(.-) and the abstraction of H- from phenylsilane.