Photo-mediated metal-free atom transfer radical polymerization: recent advances in organocatalysts and perfection towards polymer synthesis

Atom transfer radical polymerization (ATRP) is a significant improvement over traditional radical polymerization, which lacked control over molecular weight distribution and molecular weight. However, with the increasing advancement in synthetic polymer chemistry and the requirement of doing away with metal catalysts, which on one hand remain as contaminants even in trace quantities and on the other are environmentally unsustainable, catalysts that are totally organic in nature are being explored and success is being reported in the literature although in a very sparse way. This review is an attempt to give an overview of all the organic photocatalysts employed in metal-free ATRP reported from 2014. It covers the recent advancements in photoinduced metal-free ATRP and explains about the two possible mechanisms, i.e. oxidative and reductive quenching pathways, and the future direction in which this unique polymerization technique is heading. (c) 2021 Society of Industrial Chemistry.