Abstract
Electron spin resonance (ESR) spectra have been obtained for the negative ions of the nonalternant aromatic hydrocarbon Δ9,9′-bifluorene, and for its even alternant structural isomer, dibenzo(a,c)triphenylene. Coupling constants have been determined and compared with those obtained for the positive ions and with spin densities calculated from Hückel molecular orbital (HMO) theory.