Dimerization of electrochemically generated ion radicals: mechanisms and reactivity factors

Comparative studies of the reduction of 2-naphthaldehyde, 9,9′-spirobi-(9H-fluorene)-2-carboxaldehyde and 2-fluorenecarboxaldehyde in nonaqueous solvents

“…As discussed recently, the electrochemical reductive dimerization of carbonyl compounds in nonaqueous solvents occurs by the radical anion-radical anion dimerization mechanism [12]. Analysis of our data indicates that the rate constants for dimerization of the radical anions of 2-4 in DMF differ by only a factor of two showing that spiroconjugation is relatively unimportant.…”

Electrochemical reduction of 2-fluorenecarboxaldehyde: A mechanism with a grandparent–grandchild reaction

“…It is appealing as it does not require a process that localizes two negatively charged oxygen atoms on adjacent carbons in the dimer dianion to be an energetically favored reaction. However, as shown recently by Costentin and Savéant [14] for the anion radical of acrylonitrile, solvation and electrolyte effects can convert an unfavored gas-phase dimerization into an energetically favorable reaction in solution. For this reason, we have considered reaction (10) to be irreversible.…”

“…However, it is known that weak acids such as water can increase the rate of dimerization [10]. This effect, albeit with diethyl fumarate, has been interpreted as being due to association of water with the anion radical via hydrogen bonding which accelerates the rate of dimerization [14]. Thus, it was of interest to see the effect of added acids on the cathodic dimerization of 1.…”

Voltammetric behavior and square-wave voltammetric determination of trepibutone at a pencil graphite electrode

“…Consequently, the peak P 3 was the result of a twoelectron, two proton transfer. Thus, peak P 3 may be ascribed to the reduction of a dimerized free radical [22] as illustrated in the following equation:…”