Electron transfer from dibenzo[b,f]-1-azapentalene dianion: Attempted synthesis of dibenzo[b,f]-1-azapentalene

Abstract

When dibenzo[b,f]-1-azapentalene dianion (3) was allowed to react with either iron (III) chloride or ethylene bromide, a one-electron transfer from3 took place readily to give the radical anion11. Further electron transfer from11 did not occur presumably due to the antiaromatic character of dibenzo[b,f]-1-azapentalene (1) that would have resulted. The radical anion11 underwent further transformation by hydrogen abstraction from the solvent to give 5,10-dihydroindeno[1,2-b]indole (2) and by dimerization to themeso and (R,S) isomers of 5,5′,10,10′-tetrahydro-10,10′-biindeno[1,2-b]indole (4 a and4 b) respectively.