An electron spin resonance study of the fluorene radical anion in the presence of 18-crown-6 and dicyclohexyl-18-crown-6

Abstract

The e.s.r. spectrum of the fluorene radical anion has been studied in tetrahydrofuran solution in the presence of dicyclohexyl-18-crown-6 and 18-crown-6. Two superimposed spectra of the radical anion (with slightly different splitting constants) were noticeable at low temperature, particularly in the Li⁺-dicyclohexyl-18-crown-6 system. Two other effects were also observed in the low temperature spectra but to differing extents in the various systems. One of these effects may be a consequence of linewidth alternation. These results reveal the presence of a complex set of equilibria involving a variety of radical anion ‘species’ and also indicate complexation of Li⁺ by 18-crown-6 type polyethers.