The Cation Radical of Tetramethyl-2-tetrazene

Abstract

The reaction between tetramethyl-2-tetrazene and tetranitromethane in various solvents gives a relatively long-lived paramagnetic species which has been identified by its electron paramagnetic resonance spectrum as the cation radical of tetramethyl-2-tetrazene. Although the complexity of the spectrum precluded analysis by inspection, spin-coupling constants were determined by least-squares analysis of a portion of the spectrum. These parameters agreed with values obtained for similar radicals. The coupling constants (in gauss) for the radical in acetone are a(N) (2,3 positions) = 1.07 ± 0.05, a(N) (1,4 positions) = 10.93 ± 0.06, a(H) (six equivalent protons) = 10.45 ± 0.05, and a (H) (six equivalent protons) = 11.72 ± 0.05; the line width is 0.39 gauss at -30˚. The free electron spin density is estimated to be 0.42 on the 1,4 positions and 0.08 on the 2,3 positions. The relatively small nitrogen coupling constant in the 1,4 positions compared to that predicted for tetrahedral nitrogen atoms is evidence for sp² hybridization on the terminal nitrogen atoms. It is found that reactions of tetranitromethane with other materials result in paramagnetic positive ions of the oxidized species.