New Polymer-Supported Photo-Catalysts from Unimolecular, Photo-Catalyst Initiator Systems (UPCIS)

In today’s environmentally conscious world, the development of greener catalysts is at the forefront of discovery. This is because many catalysts are, traditionally, based on environmentally toxic transition metals that are discarded as waste after only a single use. In this regard, the recovery and recycling of such catalysts is vital, in academia and industry. This is often achieved through the incorporation of a catalyst and/ or ligand into a polymer support to enable liquid/liquid or solid/liquid recovery. This incorporation is frequently accomplished through (i) polymerizing a monomer that has been pre-functionalized to contain a ligand/catalyst or (ii) using a post-polymerization modification strategy in which a ligand/catalyst is linked to a pre-made polymer. However, either method relies on the synthesis of a polymer that can require multiple species of its own (i.e. monomer, catalyst, ligand, and initiator). This problem can be averted with the rational design of a unimolecular, photo-catalyst initiator system (UPCIS) that can facilitate the synthesis of a polymer support that can subsequently be used, as a multi-functional catalyst, to carry out other reactions. These systems (in which the initiator, ligand, and/ or catalyst, are covalently linked to one another) can be used to facilitate atom transfer radical polymerizations (ATRP). Additionally, the implementation of a greener energy source can be achieved through the utilization of visible light to initiate these reactions. For the current research, reactions are initiated through irradiation with visible light sources, and the catalyst is easily recovered by solid/liquid separation and can be recycled up to five times without loss of activity.