ABSTRACT
Redox-active quinones and dialkylviologens form long-lived radicals upon oneelectron reduction. These perfect storage molecules for single electrons help in light-induced charge separation reactions (photosynthesis). They also catalyze the oxidation of diamagnetic organic compounds by paramagnetic molecular oxygen (respiration). Contemporary attempts of organic chemists to mimic biochemistry (e.g., in the photochemical hydrogen evolution from water or the oxidation of hydrocarbons) often imply quinones and their nitrogen analogs, the viologens.
