Ferrocene derivatives. Part 26. The photolysis of halogenoferrocenes in aromatic solvents

Abstract

Photolysis of iodoferrocene is shown to be a useful source of ferrocenyl radicals. When these substitute arenes the ratios of arylferrocene isomers resemble the ratios of isomeric biphenyls obtained with aryl radicals. Both the high proportion of meta-isomers obtained when strongly electron-withdrawing groups are present and the small proportion of side-chain attack on toluene mark ferrocenyl as an electrophilic radical, intermediate in this respect between phenyl and 4-nitrophenyl. Bromoferrocene and diferrocenylmercury are also briefly examined as sources of the ferrocenyl radical.