The radical anion of [24](1,2,4,5)cyclophane

Reduction and oxidation of annulenes

“…Radical anions derived from cyclophanes constitute particularly promising subjects for these investigations. 293 Naturally, the benzene radical anion 2"• has attracted special interest. One main question, thereby, has concerned the vibronic interaction of the nearly degenerate electronic states93,94,242-246 in deuterium247 or alkyl12 substituted benzene radical anions.…”

Persistance of the Cyclopnane Radical Anions and its Relation to Structure

“…This spectrum (Fig., top) was analyzed in terms of the proton coupling constants given in Table 1. Guided by the hyperfine data [6], the three largest values have tentatively been assigned to the ring protons. The ESR.…”

“…spectrum of the free radical anion 3(1,2,4)0 was observed upon electrolytic reduction of the cyclophane in N,N-dimethylformamide (DMF) [8] with the use of a special cell constructed in the Base1 laboratory (tetraethylammonium perchlorate as the supporting salt). This spectrum ( Fig., top) was analyzed in terms of the proton coupling constants given in Table 1 [6], the three largest values have tentatively been assigned to the ring protons. The ESR.…”

“…and ENDOR. spectra of 4(1,2,4,5)9, the most persistent of the radical anions of all [2,]cyclophanes, can be conveniently studied up to room temperature and have recently been described [6]. The radical anions of the two remaining quadruply bridged cyclophanes, 4 (1,2,3,4) and 4 (1,2,3,5), are short-lived and yielded only spectra of secondary products.…”

“…[2.2]Meta-and paracyclophanes, 2 (1,3) and 2 (1,4), respectively, are included in the series, but 2 (1,2) is not, since this dibenzo-1,5-cyclooctadiene can hardly be considered as [2.2]orthocyclophane. For the two highest homologues with five and six ethano bridges, the notations 5 (1,2,3,4,5) and 6 (1,2,3,4,5,6) have been abbreviated to 5 and 6.…”