Synthesis of a highly iodinated biphenyl with extension of σ-delocalization

Abstract

Abstract We report the synthesis of a highly iodinated biphenyl derivative possessing two delocalized orbitals with σ-symmetry. Iodination of 2,2'-difluorobiphenyl 3 occurred by using a combination of potassium peroxodisulfate and iodine provided hexaiodobiphenyl 7. On the other hand, iodination of 3 under more harsh conditions afforded octaiodobiphenyl 4, the most iodo-substituted biphenyl, via a dibenzoiodonium intermediate. Density functional theory calculations of the thus synthesized highly iodinated biphenyl derivative show that the HOMO of 4 arises from lone-pair interactions of eight iodine atoms, indicating extension of σ-delocalization.