Monoelectronic Transfer Research Articles

The anodic behavior of saturated hydrocarbons in fluorosulfuric acid: Part I. Study of the oxidation mechanism

The mechanism of anodic oxidation of saturated hydrocarbons in fluorosulfuric acid has been established with cyclopentane and cyclohexane. Two monoelectronic transfers are separated by a chemical reaction which is a deprotonation: RH→[RH] ⋎++ e − E [RH] ⋎+→R ⋎+H + C R ⋎→R ++ e − E This ECE mechanism is supported by cyclic voltammetry and coulometries performed at cryogenic temperatures. It is shown that R is chemisorbed at low temperature: R radicals are hard and can give a complex with the platinum atoms of the anode which are also hard (because they are strongly deficient in electrons). Such a complex formation can explain why R is more difficult to oxidize than the parent hydrocarbon RH.

Detection du transfert monoelectronique dans les additions nucleophiles des reactifs organometalliques. Induction asymetrique observee avec des esters ethyleniques chiraux

In order to demonstrate mono-electron transfer in nucleophilic addition of organometallic compounds, a simple test is proposed: when the two isomers E and Z of a chiral α-β ethylenic ester give, in the reaction with the organometallic reagent, products of the same absolute configuration, then the reaction involves mono-electron transfer. The justifications and the limitations of this method are also presented. According to this test, the addition of dialkylcuprates to the electrophilic reagents used involves mono-electron transfer, but this does not apply for the addition of Grignard species.

The electrochemical behavior of the Fe(III)−Fe(II) system in strongly alkaline aqueous solutions of ethylenediaminetetraacetate ions

In strongly alkaline aqueous solutions of EDTA (Y), the Fe(III)−Fe(II) system shows a splitted anodic-cathodic polarisation curve, both parts of which correspond to a reversible monoelectronic transfer. The two related electrode reactions Fe III(OH) 4 −+ e→Fe II(OH) 3 −+OH − Fe II(OH) 2Y 4−+OH −→Fe III(OH) 3Y 4−+ e generate unstable intermediates, which are engaged in bulk chemical processes, involving respectively the addition and the abstraction of an EDTA ligand ion. Concordant values for the relevant rate constants have been obtained, for various compositions, using classical polarography, the simple potential step method and double potential step chronocoulometry. A complete quantitative scheme for the reaction mechanism has been derived from the analysis of the results.