Nonlinear Behavior during the Electrochemical Oxidation of Thiols

Abstract

The electrochemical behavior of sulfur-containing compounds is of great importance in fields ranging from diagnostics to energy-storage and materials chemistry. For example, thiols (R-SH) are important components of many electrochemical sensors and are routinely used in materials applications as they are known to form well-ordered and reproducible monolayers (self-assembled monolayers, SAMs) on various metal surfaces. Sulfur compounds are also interesting from the viewpoint of nonlinear dynamics owing to the presence of multiple oxidation states, which has been exploited to study complex dynamic behavior in both chemical and electrochemical systems. In this work we explore the oscillatory behavior of 2-(dimethylamino)ethanethiol (DMAET), a known hydrolysis product of V-type nerve agents, on platinum electrodes. Interestingly, the electrochemical oxidation of DMAET leads to two distinct regions of oscillatory behavior. Probing the system with electrochemical impedance spectroscopy (EIS), resulted in the classification of the DMAET system as an HN-NDR type oscillator. These results are compared to structurally similar thiol containing compounds towards the goal of elucidating general features which permit the evolution of dynamic behavior in thiol-based electrochemical systems.