Upconversion of Reductants

• Published in: Angewandte Chemie International Edition Vol. 58; no. 17; pp. 5532 - 5550
• Main Authors: Syroeshkin, Mikhail A., Kuriakose, Febin, Saverina, Evgeniya A., Timofeeva, Vladislava A., Egorov, Mikhail P., Alabugin, Igor V.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 16.04.2019; Wiley-VCH Verlag
• Edition: International ed. in English
• Subjects: Cascades; Chemical reactions; Chemical Sciences; Deoxyribonucleic acid; DNA; DNA repair; electron transfer; Electrons; Fireflies; fragmentations; Free energy; Organic chemistry; Peroxide; Photons; photoredox catalysis; radical anions; Redox potential; reductants; Upconversion; fragmentations; upconversion; photoredox catalysis; reductants; electron transfer; radical anions
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201807247

The many applications of photon upconversion—conversion of low‐energy photons into high‐energy photons—raises the question of the possibility of “electron upconversion”. In this Review, we illustrate how the reduction potential can be increased by using the free energy of exergonic chemical reactions. Electron (reductant) upconversion can produce up to 20–25 kcal mol−1 of additional redox potential, thus creating powerful reductants under mild conditions. We will present the two common types of electron‐upconverting systems—dissociative (based on unimolecular fragmentations) and associative (based on the bimolecular formation of three‐electron bonds). The possible utility of reductant upconversion encompasses redox chain reactions in electrocatalytic processes, photoredox cascades, design of peroxide‐based medicines, firefly luminescence, and reductive repair of DNA photodamage. Electrons and photons are essential chemical “currencies” that are commonly traded in chemical transformations. The many applications of photon upconversion raises the question of the possibility of “electron upconversion”. This Review describes the two common types of electron‐upconverting systems: dissociative (based on unimolecular fragmentations) and associative (based on the bimolecular formation of three‐electron bonds).