Electron paramagnetic resonance studies of electron capture processes. Part 8. Radical anions of N-nitroimines and nitroalkenes

Abstract

A range of N-nitroimines (1–3) and N-nitrofluorene-2-imine (4), in dilute solutions of methyl-tetrahydrofuran and CD₃OD, exposed to ⁶⁰Co γ-rays at 77 K, gave the corresponding radical anions, detected by EPR spectroscopy. Analysis of the spectra shows that the radical anions of the aliphatic N-nitroimines 1–3 have the unpaired electron in the π*-NO₂ molecular orbitals, and that the radical anion of the aromatic N-nitroimine 4 is delocalised in the aromatic π molecular orbitals. The EPR spectra of the radical anions of nitroalkenes 5–8, prepared in the solid state by similar methods, have been studied and compared with the radical anions of the N-nitroimines. Analysis of the EPR spectra indicates that the unpaired electron in the radical anions of the N-nitroimines is more centred on the nitro group than in the nitroalkenes.