Photon Upconversion in Supramolecular Gels and Synthetic Application

Self-assembled supramolecular gels have recently emerged as promising confined media for the incorporation of a wide range of donor–acceptor chromophoric assemblies, allowing highly efficient photon upconversion processes at weak solar irradiance even under aerobic conditions in some cases. Supramolecular gels made of dense intermolecular interaction networks such as hydrogen bonding have been demonstrated to offer effective protection to the excited species against oxygen quenching. This supramolecular approach is reminiscent to biological photon-harvesting systems and constitutes a new paradigm in photon upconversion research. This minireview summarizes the advances in this approach since its first report a few years ago. The possibility of carrying out photon upconversion in supramolecular gel matrices under aerobic conditions has also enabled to combine this process with a single electron transfer in order to carry out challenged chemical reactions such as the photoreduction of aryl halides in air using visible light. The main aspects of this combined strategy and future perspectives are also discussed.