Kinetics of electrode reduction of the tetrachlorocuprate(II) ion: an example of the concerted EC reaction mechanism

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

“…The C d -E results, however, indicated that a minimum at À 0.17 V vs Ag/Ag þ , which could have represented the pzc, was dependent on the TBAP concentration. Results reported for the GC electrode in MeCN/ Et 4 NCl provided a very positive pzc value [50], which can be estimated to be ca. 0 V vs. ferrocene/ferricenium.…”

Electrochemical Investigation of Redox Processes of Labile Cu(II)/Cu(I)-Cl Complexes by Scanning Electrochemical Microscopy

“…From Table , one can see that much smaller rate constants were obtained for the reduction of [Cu II Cl 3 (H 2 O)] − , compared to that of Cu II Cl 4 2– . Few examples of metal complexes have been documented of EC reactions with the concerted mechanism, but this type of process is very much analogous to more widely studied “dissociative electron transfer”. − For the dissociate ET reactions, evidences have been shown that the rate decrease was usually accounted for by a change of the activation free energy , or the pre-exponential factor in Marcus theory. , The latter factor was often with the nonadiabatic ET process.…”

“…The E T C reaction of Cu II Cl 4 2− to Cu I Cl 3 2− follows a stepwise pathway, 20 and (EC) T ' reaction of Cu II Cl 3 (H 2 O) − to Cu I Cl 3 2− is more consistent with a concerted mechanism, where the electron and ligand transfer steps can proceed almost simultaneously. 15,21 Evidently the difference in reaction mechanism between these two complexes is dictated by the strength of the metal−ligand bond. The concerted pathways occur more often under conditions of weak bond, poor oxidability of the leaving groups, suggested by Andrieux et al 27 A two-dimensional axial symmetrical model of SECM was developed by using COMSOL Multiphysics software to obtain the kinetic parameters (SI, appendix).…”

“…It is clear that Cu II Cl 4 2– complex species is dominant in 9 M LiCl. The reduction of Cu II Cl 4 2– should follow an EC sequence but either stepwise or concerted mechanism is conceivable, even though the reduction product, Cu I Cl 4 3– is known to be inherently very unstable and short-lived (τ lig = 10 –8 ∼10 –10 s) . Recent studies have found that its reversibility depended heavily on the nature of solvent. , There is evidence that Cl – ions and solvent molecules (H 2 O) compete for inner coordination sites of Cu 2+ .…”