Synthesis of Conjugated Polymers by Infrared Photoredox Catalysis

To date, there are no commodity plastics based on rigid-rod conjugated polymers. We argue that it’s because the chemistry to synthesize such materials has not caught up with the development of synthetic strategies for non-conjugated systems. In a high-risk approach that bears the ultimate reward of conjugated polymer chemistry, this proposal focuses on exploiting photoredox chemistry with infrared light as a polymerization method specifically targeting conjugated organic polymers. Photopolymerization of conjugated polymers with high-energy photons (visible-to-ultraviolet) has led to small conjugated oligomers and limited control in polymers with electron-deficient units due to competitive light absorption between the photocatalyst and the growing conjugated polymer, thus paralyzing the activity of the photocatalyst. However, this can be overcome using triplet fusion (TF) upconversion to activate photocatalysts using the upconverted energy - a process that was pioneered in the Campos lab at Columbia University.