Radical-anion intermediates. Part V. Electron spin resonance spectra of radical anions and dianion radicals of some 9-substituted fluorenes

Abstract

The e.s.r. spectra of the radical anions and dianion radicals obtained from eight 9-substituted fluorenes have been studied. The e.s.r. spectra of the radical anions have been satisfactorily interpreted. In many of the spectra a small splitting associated with the substituent is present. The variation of the a_β(H) coupling constant with substituent can be satisfactorily interpreted in terms of either the steric or the polar nature of the substituent. In the case of the dianion radicals the e.s.r. spectra are all fairly similar. However, in three of the dianion radicals studied the e.s.r. spectra are best interpreted in terms of two radicals with g values differing by 0·00006.