SUBSTITUTED DIAZACYCLOPENTADIENONE ANION RADICALS

A series of substituted 3,4-diazacyclopentadienone N, N-dioxides and N-oxides were synthesized and their anion radicals were generated via low-temperature potassium metal reduction in tetrahydrofuran. The ESR coupling constants in conjunction with INDO spin density calculations indicate that the spin and charge densities are nearly equally distributed between the ring system and the carbonyl oxygen. The stability of the anion radicals is attributed to the formation of tight ion pairs with the potassium cation. This tight ion association splits the degeneracy of the four nitrogens in the anion radical of 2,2',5,5'-tetraphenyl-3,3',4,4'-tetraazafulvalene 3,3',- 4,4'-tetraoxide. The anion radical of 2,5-diphenyl-3,4-diazacyclopentadienone MN-dioxide loses an oxygen ato upon warming, leaving the anion radical of the corresponding IV-oxide. © 1979, American Chemical Society. All rights reserved.