Adducts of group 4B organometallic radicals with quinones and aromatic ketones: An electron resonance investigation

The e.s.r. spectra of free radicals obtained by addition of silyl, germyl, and stannyl radicals to acenaphthoquinone, 9,10-phenanthroquinone, a number of para-quinones, benzophenone, and fluorenone have been investigated over a range of temperatures. A number of the adducts exhibit line-width alternation in their e.s.r. spectra. Activation parameters are reported for intramolecular migration of triphenylgermyl, tri-n-butylgermyl, and tri-n-butylstannyl groups between the two oxygen atoms of acenaphthoquinone. This is the first measurement of an activation barrier for an adduct of a tin-centred radical.