Electron Spin Resonance of γ-Irradiated Triglycine Sulfate. I Hindered Motion of CH²in a Free Radical CH²COO^-

Three species of radicals were observed. One of these was already identified as HN ₃ \(\dot{\text{C}}\)HCOO ^- by Ovenall et al. and by Blinc et al. . One of the other species, which appears as a triplet with an intensity ratio of 1:2:1, is identified as \(\dot{\text{C}}\)H ₂ COO ^- . The principal values of A - and g -tensor of the radical are determined to be 25.1, 19.6 and 16.7 gauss and 1.9994, 1.9999 and 2.0009, respectively. From the temperature dependence of the spectra, it is concluded that the two protons in the \(\dot{\text{C}}\)H ₂ COO ^- exchange their sites with each other through a rotation of the \(\dot{\text{C}}\)H ₂ group about the C–C _N bond.