redoxkoppel

Redoxkoppel is a term used in electrochemistry and materials science to describe a specific kind of electronic coupling between redox-active centers within a molecule or material. The concept highlights how oxidation and reduction sites influence one another through a connecting link, thereby altering redox potentials, electron-transfer rates, and overall reactivity. The word blends redox with koppel, a German root meaning coupling, and is used in theoretical discussions and model systems to emphasize cooperative effects in dinuclear, oligomeric, or polymeric redox platforms.

Mechanistically, redoxkoppel can arise from through-bond coupling via a π-conjugated bridge or from through-space interactions when redox centers are in close proximity. The effective coupling strength is described by parameters such as J or H_ab, which govern the splitting of redox potentials, intercenter electron transfer rates, and comproportionation constants.

In practice, redoxkoppel is invoked to rationalize observations such as paired redox waves in cyclic voltammetry, enhanced electronic communication in metal–ligand assemblies, or synchronized oxidation events in conductive polymers. It is distinct from a redox mediator, which is an independent species that shuttles electrons; redoxkoppel refers to intrinsic inter-center interaction within a single system.

Applications of the concept include the design of molecular wires, multi-electron redox catalysts, and tunable redox-active materials for energy storage. See also electronic coupling, Marcus theory, redox chemistry, and electron transfer.