THE ESR SPECTRA OF THE NITROTROPOLONATE ANION RADICALS
Electrolyses of 5-nitro-, 3-nitro, and 3,5-dinitro-tropolones in N,N-dimethylformamide generated the corresponding tropolonate anion radicals. Hyperfine structures in the ESR spectra of the radicals were reasonably explained by the spin density calculations. The results for the 3-nitro- and 3,5-dinitro-tropolonates suggested that the 3-nitro groups were twisted about 40 and 55°, respectively, from the ring plane.