Radical-anion intermediates. Part I. The fluorene radical anion

Abstract

The reaction of fluorene with alkali metals at –70° gives the fluorene radical anion. This decays at higher temperatures to the fluorenyl anion. The rate of the decay was found to be very sensitive to the nature of the counterion, i.e., ΔG‡ decreased markedly in the order Li⁺ > Na⁺ > K⁺ > Cs⁺. The decay can be of either the first or the second order, depending upon the nature of the counterion and of the solvent, and also on temperature. The e.s.r. spectrum of the radical anion has been studied and can be interpreted in terms of five sets of two equivalent protons.