Cross-dimerization of nitrosobenzenes in solution and in solid state

Cross-linking of nitrosobenzenes to heterodimers (azodioxides) when they are not sterically crowded with large groups in ortho-position was studied by NMR and FT-IR spectroscopy, X-ray crystallography as well as by cryogenic photolysis. It was found for the first time that cross-linked dimers (heterodimers) exist both in solution and in solid state and that they appear in the crystal together with homodimers. The system is used as a model for studying organic solid solution formation. The role of molecular packing in formation of a weak chemical bond is also discussed.