An electron spin resonance study of the reactions of organosilicon, organogermanium, and organotin radicals with carbonyl compounds

Abstract

Addition of organosilyl, organogermyl, organotin, and organolead radicals to the oxygen atom of carbonyl compounds has been investigated by e.s.r. spectroscopy. Ease of addition, to a given carbonyl compound, falls in the order R₃Si· > R₃Ge·∼ R₃Sn· > R₃Pb·, and for a given Group IV_B radical, diketones > oxalates > ketones > trifluoroacetates > formates > acetates. The results are rationalized in terms of bond energy differnces, stabilization of radicals formed, and polar effects. Tris(trimethylsilyl)silyl is less reactive than triethylsilyl. Organotin radicals react with α-diketones, oxalates, to give spectra which are best interpreted as being due to radical anions.