Radicals in prebiotic chemistry
Abstract Radical chemistry is tightly interwoven in proposed prebiotic synthetic pathways, reaction networks and geochemical scenarios that have helped shape our understanding of how life could have originated. Gas-phase prebiotic reactions involving electric discharge, vapour ablation by asteroidal and cometary impacts as well as ionising radiation all produce radicals that facilitate complex molecular synthesis. Reactions in the solid phase which are responsible for astrochemical syntheses can also take place through radicals produced via irradiation of protoplanetary/interstellar ice grains and dust particles. Aqueous-phase radical chemistry affords further molecular complexity promoting the production of precursors for the synthesis of biopolymers thought important for the emergence of life. Radical chemistry appears to be a common thread amongst all kinds of prebiotic investigations, and this Review aims to bring attention to a few selected examples. Some important historical studies and modern developments with respect to prebiotic chemistry are summarised through the lens of radical chemistry.