Electron-transfer bond-breaking processes: an example of nonlinear activation-driving force relationship in the reductive cleavage of the carbon-sulfur bond

Electron Transfer to Sulfides and Disulfides: Intrinsic Barriers and Relationship between Heterogeneous and Homogeneous Electron‐Transfer Kinetics

“…Here k d is the diffusion‐controlled rate constant in DMF (8.7×10 9 M −1 s −1 )15c and Z hom the collision frequency (average value 3×10 11 M −1 s −1 ), given by Z = d 2 [8π k B T / μ ] 1/2 , where d is the encounter distance, k B the Boltzman constant, and μ the reduced mass);9a the solution ET is considered adiabatic. Δ G ≠ can be expressed either as in the Marcus equation [Eq.…”

“…Sulfides 1 and 2 were synthesized from the appropriate thiophenol and diphenylmethanol or triphenylmethanol in acetic acid with H 2 SO 4 , and recrystallized from ethanol 4a. 15c, 16, 20 Dibenzyl disulfides 3 were prepared by the following steps: reaction of the appropriate benzyl bromide with potassium acetate to yield an acetylsulfanyl methylbenzene derivative, transformation of the latter into the thiol under acidic conditions, and oxidation of the thiol to the disulfide with iodine. Full details of the syntheses of sulfide 1 h and disulfides 3 are provided in the http://www.wiley-vch.de/contents/jc_2111/2007/f700382_s.pdf.…”

“…This is partly because these DET reactions appear to be particularly suited to give rise to mixed mechanistic behaviors, as already observed and/or discussed 1. 4a, 15, 16 For example, certain sulfides are reduced with substantial inner reorganization caused by CS bond elongation on radical‐anion formation 15c,d. In one case, some evidence for a concerted‐to‐stepwise mechanistic transition induced by driving force was obtained by studying the dissociative reduction of triphenylmethyl phenyl sulfide by a series of solution one‐electron donors,4a though a different selection of mediators did not reveal the same activation/driving force trend 16.…”

Double‐Layer Correction for Electron‐Transfer Kinetics at Glassy Carbon and Mercury Electrodes in N,N‐Dimethylformamide

“…These DETs are thus endowed by rather large DG 0 = values, though not as large as for concerted DETs. Examples of such reactions are not uncommon, as we could demonstrate in a series of studies on the reduction of disulfides [40 -42] and sulfides [43,44].…”

Mathematical Modeling of Electrode Processes – Potential Dependent Transfer Coefficient in Electrochemical Kinetics

“…for chromatography data with the use of respective mathematical model (Kaczmarski, 2007;Kim et al, 2005Kim et al, , 2006a The reduction process going through two one-electron steps with chemical reaction between them is typical for a large number of processes in both organic and inorganic electrochemistry and is still of current interest e.g. (Andrieux et al, 1992;, 1994, 1997Antonello & Maran, 1997, 1998Antonello et al, 2001Antonello et al, , 2002aAntonello et al, , 2002bCostentin et al, 2009;Jaworski & Leszczyński, 1999;Najjar et al, 2007;Pause et al, 1999Pause et al, , 2001Savéant, 1987Savéant, , 1992Savéant, , 1993Severin et al, 1993;Speiser, 1996a;Workentin et al, 1995).…”