Metal-free atom transfer radical polymerization: reaching ppm catalyst loading under sunlight

Abstract Organocatalytic atom transfer radical polymerization (O-ATRP) is recently emerging as an appealing method for the synthesis of metal-free polymer materials with well-defined microstructures and architectures. However, the development of highly effective catalysts that can be employed at a practical low loading are still a challenging task. Herein, we introduce a catalyst design logic based on heteroatom-doping of polycyclic arenes, which led to the discovery of oxygen-doped antratherene (ODA) as a new class of organic photoredox catalysts for O-ATRP. In comparison with known organocatalysts, ODAs feature strong visible-light absorption together with high molar extinction coefficient (ε455nm up to 23950 M–1cm–1), which allow for the establishment of a controlled polymerization under sunlight at low ppm levels of catalyst loading.