Tailoring of organic dyes with oxidoreductive compounds to obtain photocyclic radical generator systems exhibiting photocatalytic behavior

International audience; The combination of a dye which absorbs the photon, an electron acceptor and an electron donor leading to energy conversionthrough electron transfer, was the basis of the so called three-component systems. In this paper, an experimental work combiningRose bengal dye with a triazine derivative as electron acceptor and ethyl 4-(dimethylamino)benzoate as electron donor, will underlinethe benefit of the photocyclic behavior of three-component systems leading to the dye regeneration. A thermodynamic approachof the photocycle is presented, followed by a mechanistic and computational study of ideal photocycles, in order to outlinethe specific kinetics occuring in so called photocatalytic systems. The simple kinetic model used is enough to outline the benefit ofthe cyclic system and to give the basic requirements in term of chemical combination needed to be fulfilled in order to obtain aphotocatalytic behavior.