Visible-Light-Induced Chlorine Photoelimination from Acridinium-Phosphine Gold(III) Complexes

Abstract

With the objective of developing transition metal complexes that undergo visible-light-induced halogen photoelemination, we have successfully synthesized trivalent gold trichloride complexes featuring an acridinium unit. Photoexcitation of the acridinium π+ system with green light allows for facile photoreduction to the corresponding AuI complexes, highlighting the photolability imparted by this moiety onto the AuIII center. The photolysis is remarkably clean, particularly in the solid state where the photodechlorination is essentially trap-free. Transient absorption spectroscopic studies reveal that the photochemistry is derived from a pathway whereby the S1 excited state of the acridinium undergoes energy transfer to the AuIII center to prompt the photogeneration of Cl radicals.