The Anion Radical of Bicyclononatriene

Article abstract of DOI:10.1021/ja00038a010

The low-temperature potassium metal reduction of bicyclo<6.1.0>nona-2,4,6-triene (BCN) in DME leads to the formation of the previously observed open form of the homocyclooctatetraene anion radical (HCOT anion radical).Careful inspection of the EPR spectra recorded from these solutions, and some of those previously published, shows the presence of another species.This second species is best interpreted using a set of methylene proton coupling constants very similar to those of HCOT anion radical (all within 10percent) but much smaller endo and exo bridgehead coupling constants.Perdeuteriation of of the sp² carbons supports this interpretation.The only reasonable interpretation of the hyperfine pattern observed for the second anion radical is in terms of the closed (bicyclic) form.The closed anion radical (BCN anion radical) is favored under conditions involving more ion association and more complete reduction.