Halogen Bonding in Electrochemistry

In electrochemical reactions noncovalent interactions are crucial and have been extensively studied in the context of electrolyte composition (solvent and supporting electrolyte salt) and interfacial electron transfer processes. More recently an increasing interest in "supramolecular electrochemistry" can be observed concerning the electrochemical reactivity of supramolecular assemblies in homogeneous solution and surface-confined systems. In this context halogen bonding (XB) has been studied yet only via few examples reported in the literature. This chapter resumes all aspects of investigating or applying XB as an identified interaction in electrochemical reactions in solution or at the solid/liquid interface. Solid-state electrochemistry is not treated. Concepts such as electrochemical XB activation and XB redox switching and the use of electrochemistry as a tool for detecting and controlling XB are reported in the context of molecular recognition and detection. In an effort to present comparable quantitative data, reported and calculated thermodynamic affinity constants and binding energies are assembled. First evidence for XB-promoted electron transfer reactions involving the activation of covalent bonds and the simultaneous development of XB-based organocatalysis are pointing toward a novel and promising direction of reactivity.