Preparation and X‑ray Structural Study of Dibenziodolium Derivatives

New
experimental procedures for the preparation of dibenziodolium
salts by oxidative cyclization of 2-iodobiphenyl in the presence of
appropriate strong acids are described. Particularly useful is a convenient
one-pot synthesis of dibenziodolium hydrogen sulfate from 2-iodobiphenyl
using Oxone as an inexpensive and environmentally safe oxidant. Dibenziodolium
hydrogen sulfate, bis­(triflyl)­imidate, or triflate can be readily
converted to various other dibenziodolium derivatives (chloride, bromide,
thiocyanate, azide, cyanide, phenylsulfinate) by anion exchange. Structures
of key products have been established by single-crystal X-ray diffraction
analysis. Particularly interesting is the X-ray structure of dibenziodolium
thiocyanate, which represents the first example of a structurally
characterized hypervalent iodine compound with a relatively short
iodine–sulfur secondary bond distance.