Spectroelectrochemical approaches to heterogeneous electron transfer reactions at the polarised water vertical bar 1,2-dichloroethane interfaces

Heterogeneous electron transfer (ET) reactions at the polarised water \ 1,2 -dichloroethane (DCE) interface are studied by in situ W-Visible spectrosco py in total internal reflection mode. The reduction of 7,7,8,8-tetracyanoqu inodimethane (TCNQ) and the oxidation of I,1'-dimethylferrocene (DMFc) by t he hexacyanoferrate redox couple are considered. The generation of products in the organic phase is monitored spectroscopically and correlated to the simultaneous current response. Both systems exhibit a good correlation betw een optical and electrochemical responses, highlighting the ideal behaviour of these redox couples for electron transfer studies at liquid\liquid inte rfaces. The kinetics of ET between hexacyanoferrate and TCNQ is analysed al so by chronoabsorptometry and potential modulated reflectance spectroscopy. The potential dependence of the ET rate constant is discussed within the f ramework of the ET models for ITIES. (C) 1998 Elsevier Science S.A. All rig hts reserved.