4-Iodonitrosobenzene. Structural and spectroscopic studies of the monomeric solid and of previously unreported dimers

Abstract

4-Iodonitrosobenzene has been isolated as the (E)-azodioxy dimer for the first time. Its solid-state structure has been identified by X-ray crystallography and characterised by IR, MS and ¹³C NMR techniques. In CDCl₃ or CD₂C1₂ solution dynamic equilibria exist between monomeric 4-iodonitrosobenzene and its (Z)- and (E)-azodioxy dimers. Thermodynamic data (ΔG^⊖, ΔH^⊖ and ΔS^⊖) for these equilibria have been calculated from low temperature ¹H NMR spectra. Criteria for the dimerisation tendencies of all types of C-nitroso compounds are proposed.