One-Electron Reduction of 2-Nitrotoluene, Nitrocyclopentane, and 1-Nitrobutane in Room Temperature Ionic Liquids: A Comparative Study of Butler–Volmer and Symmetric Marcus–Hush Theories Using Microdisk Electrodes

Abstract

The voltammetry for the reduction of 2-nitrotoluene at a gold microdisk electrode is reported in two ionic liquids: trihexyltetradecylphosphonium tris(pentafluoroethyl)trifluorophosphate ([P 14,6,6,6 ][FAP]) and 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim]-

Towards Understanding the Solvent‐Dynamic Control of the Transport and Heterogeneous Electron‐Transfer Processes in Ionic Liquids

“…Furthermore, double-potential-step CA was performed to monitor the variation of the D R /D O ratio. The D R /D O ratio of 1.69 estimated at 298 Km atches well with that reported for ferrocene (Fc) in [BMIM][PF 6 ]. [39] Such at rend is also seen in kinetic data reported by Matsumiya et al for Fc in an IL.…”

“…t)f or the coulometric data recorded in presence of EFc are similara nd equal tot hat of the intercept of the Q d (t t)versus t 1/2 plot for the CC response in the absence of EFc. This establishes that both EFc andE Fc + are stable and not adsorbed during the redox cycle at the glassy carbon (GC) electrode and hence support the use of EFc/EFc + as an inter-nal reference standard redox couple that can be recommended for potential-scalecalibrations in [BMIM][PF 6 ].…”

“…To ascertain the stability of the oxidised and reduced forms of the redox couple on ET,l arge-amplitude double-potentialstep CC experiments were performed, both in the presence and in the absence of EFc in [BMIM][PF 6 ]. The recorded data are presented as an Anson Plot in Figure 4.…”

“…The impact of temperature-inducedc hanges in solventdynamics on the diffusion coefficient and standard rate constant k 0 for heterogeneouse lectron transfer (ET) of ethylferrocene (EFc) in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] [PF 6 ]) is investigated. The results are analysed to understand the impact of solvent-dynamic control, solute-solvent interactions and solvent friction on the transport of redox probesa nd k 0 .C oncentration dependence of the diffusionc oefficient of EFc in [BMIM][PF 6 ]i so bserved.T his is attributed to the soluteinduced enhancement of the structural organisation of the ionic liquid (IL), which is supported by the concentration-de-pendentU V/Vis absorption and photoluminescence responses of EFc/[BMIM][PF 6 ]s olutions. Similarv alues of the activation energies for mass transport and ET andalinear relationship between the diffusion coefficient and the heterogeneous ET rate is observed.…”

“…The resultsw ere analysed to unravel the impact of solvent-dynamic control, solutesolventi nteractions and solventf riction in the transporta nd heterogeneous ET kinetics of redox probes. 6 ]. The peak-to-peak separation and peak width of 58 mV suggest that this is ao ne-electron reversible redox system.A lmost perfect agreement between the experimental and simulated (by using the reversible ET approximation) CVs ( Figure 1) attests to this hypothesis.…”