A numerical modelling of voltammetric reduction of substituted iodobenzenes reaction series. A relationship between reductions in the consecutive-mode multistep system and a multicomponent system. Determination of the potential variation of the elementary charge transfer coefficient

The cyclic voltammetry reduction process of the reaction series of substitu ted iodobenzenes X-C6H4-I where X = H, p-Cl, p-Br, p-I. p-CH3, m-CF3 was in vestigated in 0.3 M TBAP in DMF. A numerical model of the process consisten t with the ECE mechanism of mono-iodobenzenes reduction and consecutive ECE -ECE reduction of p-diiodobenzene was applied. On the basis of alpha (i) vs . E-p,E-i dependence. the value of partial derivative (alphai)/alphaE was f ound to be 0.37 +/- 0.07 for first electron transfer (Eq. (10). The ECE-ECE system seems to be an another example of elementary alpha kinetic discrimi nation between two identical two-electron processes analogous to that descr ibed in a previous paper (Sanecki, P.. Kaczmarski, K. (1999). J. Electroana l. Chem. 471, 14 and erratum to it (2001)). A method of simultaneous treatm ent of the substrate and all electroactive intermediates, i.e. the transfor mation of any experimental consecutive CV reduction curves (e.g. ECE or ECE -ECE) into curves corresponding to reduction of the multi-component systems is presented and discussed. (C) 2001 Elsevier Science Ltd. All rights rese rved.