Structure and fluxional behaviour of the adducts of orthoquinones with organotin halides. An electron spin resonance study

Free radicals observed in reactions of acenaphthoquinone (AQ) and benzo[2,1-b;3,4-b']dithiophen-4.5-dione (TQ) with the series of compound SnPhnX4-n (n = 3, X = H, Cl; N = 2, X = Cl; n = 0, X = Cl) have been characterised by esr spectroscopy. Coupling to only a single chlorine nucleus is detectable in radical adducts containing two or thee chlorine atoms. The implications of this observation are discussed in terms of structures involving a five-coordinate tin atom. Activation parameters are rported for the intramolecular migration of SiPh3 and GePh3 groups between the oxygen atoms of TQ.