On the nature of nitrogen–nitrogen bonding in cyclic aminimides

Abstract

The bonding character of cyclic aminimides has been studied by X-ray photoelectron spectroscopy (XPS). The electron density on the quaternary nitrogen atom of cyclic aminimides is much higher than that of the corresponding salts, and the differences Δ(N⁺–N^–) between the nitrogen 1s binding energies of the quaternary nitrogen(N⁺) and the anionic nitrogen(N^–) are smaller than those in open-chain aminimides. These results indicate that the cyclic aminimides are considerably stabilized by displacements of σ electrons in the N–N bond toward the quaternary nitrogen. XPS and i.r. data also show the stabilization of the cyclic aminimides by amide resonance.