Unstable intermediates. Part 175. Effect of ionizing radiation on N-nitrosodimethylamine: an electron spin resonance study

Abstract

Exposure of N-nitrosodimethylamine to ⁶⁰Co γ-rays at 77 K gave two paramagnetic centres detected by e.s.r. spectroscopy. One had hyperfine coupling to two non-equivalent nitrogen atoms whose estimated isotropic coupling constants agreed with those for the anions R₂NNO^– in fluid solution. These anions, formed in methanol at 77 K, became protonated on annealing. The other centre had a large isotropic coupling (ca. 40 G) indicative of a σ-radical, and we suggest that it is the species Me₂NṄO⁺, which is isoelectronic with the well known iminoxyl radicals, R₂CNO. The results indicate an increased spin-density on nitrogen on going from R₂CṄO to R₂NṄO⁺.