127I Moessbauer spectra of diphenyliodonium halides

The 127I Moessbauer spectra have been obtained at 20 K for the diphenyliodonium halides, Ph2IX (X = Cl, Br) and their derivatives, (p-R-C6H4) IPhBr (R = CH3, CH3O, Cl, COOH and NO2). The valence electron populations of iodine are determined by the interactions with carbon atoms but not with bridging halogen atoms. The iodine-carbon bonds, having large p-character, are affected scarcely by the substituents at the para-position of the phenyl group. The large η values for those compounds are explained in terms of a lone pair electrons on iodine(III) atoms. (author)