Halogenation of calix[4]arenes by [I(py)(2)]I-3 center dot 2I(2)

The iodination of calix[4]arene and one of its monofunctionalised derivatives by bis(pyridine) iodonium(I) triiodide, [I(py)(2)]I-3 center dot 2I(2) has been studied. The iodination reactions proceed in good yields at room temperature (r.t.) without any co-reagents affording the corresponding tetra- and tri-substituted calix[4]arenes. Only electron-rich phenol groups are iodinated by [I(py)(2)]I-3 center dot 2I(2). Phenolether or Schiff-base type arene rings remain unaffected. The crystal structure of the iodination reagent, first published in 1961, has been re-determined which a higher precision. The crystal structures of the two per-iodinated calix[4]arenes show that self-inclusion occurs in the solid state.