Norrish type I photochemistry as a powerful tool in the isolation of thiol protected Au 25 SR 18 clusters

Abstract Metal clusters are a class of materials that exhibit highly tunable optical and electronic properties. The library of atomically precise clusters is rapidly growing, and the unique optical properties make clusters attractive materials for catalysis, photocatalysis [1] , [2] , and photonics applications [3] . Thiol protected gold clusters, like Au 25 SR 18 , are among the most highly studied [4] , [5] , [6] , [7] . Synthesis and isolating of atomically precise clusters are typically challenging, with only small changes in the choice of ligands and/or the rate of addition of reducing agents often resulting in drastically different clusters [5] , [8] . Herein we report on a photochemical route for producing atomically precise gold clusters. The synthesis of Au 25 SR 18 via a photochemical initiator, allows for timed delivery and in operando modulation of the concentration of reducing species, providing unprecedented control over the most challenging aspects of metal cluster synthesis.