SEQUENTIAL PHOTOCHEMICAL REACTION IN DYE/CLAY HYBRID SYSTEM

Abstract

Photochemistry of molecules on the surface or in the interlayer space of clay nanosheets has attracted broad attention due to the unique microenvironments provided by the clay. Extensive research has been conducted on dye/clay hybrid systems, including unimolecular, bimolecular, and more complex photochemical reactions. This short review focuses on sequential photochemical reactions involving three types of molecules. The first part presents excitation energy transfer followed by photoinduced electron transfer between molecules assembled on clay nanosheets, facilitated by an organic cavitand to achieve a designed reaction sequence. Excitation of the energy donor resulted in energy transfer efficiencies of 67–73%, sequential electron transfer efficiencies of up to 81%, and less than 5% energy loss. The second part describes a photooxidation reaction mediated by singlet molecular oxygen, generated through energy transfer from a hybrid of cationic phthalocyanine and saponite nanosheets. The effect of phthalocyanine adsorption density on singlet oxygen generation efficiency and the underlying mechanism are also discussed.