9-Fluorenyl anions, oxidation

That is, just as oxidation of tetrabenzo[5.5]fulvalene resulted in formation of two antiaromatic fluorenyl cations linked by a single bond, reduction should give two aromatic fluorenyl anions, linked by a single bond, 20. We call this relationship the aromaticity/antiaromaticity continuum and can apply the same measures of aromaticity to 20 as were applied to 3, to evaluate relative aroma-... 

The rates of oxidation of fluorenyl and diphenylmethyl anions are correlated by simple Hiickel MO calculations. Loss of an electron from fluorene anion involves electron transfer from a bonding orbital (0.18 / ). On the other hand, the electron lost from the diphenylmethide ion will come from a nonbonding orbital. Thus, the transfer of an electron to oxygen will occur more readily from the diphenylmethide ion than from the fluorenyl anion. 

A typical cyclic voltammetric trace for the anodic oxidation of the fluorenyl anion 2 at platinum is shown in Figure 1. The oxidation potential for this and several other resonance stabilized carbanions lies conveniently within the band gap of n-type Ti02 in the non-aqueous solvents, and hence in a range susceptible to photoinduced charge transfer. Furthermore, dimeric products (e. g., bifluorenyl) can be isolated in good yield (55-80%) after a one Faraday/mole controlled potential (+1.0 eV vs Ag quasireference) oxidation at platinum. 

Hie cleavage of ethylene oxide by alkali salts of 9-methyl-fluorenyl anion was investigated in several ethereal solvents by Sigwalt and Boileau112. At a salt concentration lower than 1(T4 M, the reaction is first order in the oxide and in the salt. However, at... 

The mechanism of the reaction depicted in Scheme 4.6 differs from the Sf.,1 or Sf.,2 mechanism in that it involves the stage of one-electron oxidation-reduction. The impetus of this stage may be the easy detachment of the bromine anion followed by the formation of fluorenyl radical. The latter is unsaturated at position 9 near three benzene rings that stabilize the radical center. The radical formed is intercepted by the phenylthiolate ion. This leads to the anion-radical of the substitution product. Further electron exchange produces the substrate anion-radical and final product in its neutral state. The reaction consists of radical (R)-nucleophilic (N) monomolecular (1) substitution (S), with the combined symbol Sj j l. Reactions of Sj j l type can have both branch-chain and nonchain characters. 

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