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

Novel studies about the electrochemical reduction of progesterone (P4) in acetonitrile at glassy carbon electrodes

“…The source of acetonitrile anion was thought to be via reactions such as the protonation of an organic dianion by ACN [29]. Recently, it has been emphasized the complexity that can occur under electrolytic conditions [30]. In agreement with a previous report [30], such reactions may underlay the larger than unity n-values that were observed also in the present work.…”

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

“…If the reaction is a fast, reversible process, if the equilibrium constant for dimerization is small, and if reactions (11) and (12) are fast and irreversible, the rate law for disappearance of HFluorCHO ÀÅ will be exactly the same as for the irreversible dimerization. This was the interpretation offered for the effect of water on the rate of dimerization of the anion radicals of 2-naphthaldehyde [10]. 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.…”

“…There is some question about the reversibility of reaction (10). If the reaction is a fast, reversible process, if the equilibrium constant for dimerization is small, and if reactions (11) and (12) are fast and irreversible, the rate law for disappearance of HFluorCHO ÀÅ will be exactly the same as for the irreversible dimerization.…”

“…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].…”

“…In a recent study of the reduction of 9,9 0 -spirobi-(9H-fluorene)-2-carboxyaldehyde [10], 2-fluorenecarboxyaldehyde was used as a model to interpret the electrochemistry of the spiro compound. It was observed that some sort of a ''parent-child'' reaction was occurring but the complete description of the mechanism was deferred.…”