The reactions of phenyl( B-carboranyl)iodonium salts with nucleophiles

Abstract

The reactions of phenyl(9- o-carboranyl)-, phenyl(9- m-carboranyl)- and phenyl(2- p-carboranyl)-iodonium salts with the nucleophiles F −, Cl −, Br −, OH −, C 5H 5N, Hg and CN − were studied. Depending on the nature of the nucleophile and the carborane ligand in each iodonium compound, these reactions either proceed as nucleophilic substitution or via a radical mechanism. Nucleophilic substitution, which takes place at the boron atom, of the carborane nucleus only, gives “carboranylation” products of nucleophiles. Free-radical processes are characterized by breaking of the CI + bonds with the formation of phenyl radicals and their transformation products. The reasons for such an unusual behaviour of phenyl( B-carboranyl)iodonium salts in reactions with nucleophilic agents are discussed in the light of the results obtained and previous results.