Light-induced Polymeric Frustrated Radical Pairs as Building Blocks for Materials and Photocatalysts

Polymeric frustrated Lewis pairs, or poly(FLP)s, have served to bridge the gap between functional polymer science and main group catalysis, pairing the uniqueness of sterically frustrated Lewis acids and bases with a polymer scaffold to create self-healing gels and recyclable catalysts. However, their utilization in radical chemistry is unprecedented. In this paper we disclose the synthesis of polymeric frustrated radical pairs, or poly(FRP)s, by in-situ photo-induction of FLP moieties, where their Lewis acidic and basic centres are tuned to promote single electron transfer (SET). Through systematic manipulation of chemical structure we demonstrate that inclusion of ortho-methyl groups on phosphine monomers is crucial to enable SET. The generation of radicals is evidenced by monitoring the stable polymeric phosphine radical cations via UV/Vis and EPR spectroscopy. These new poly(FRP)s enable both catalytic hydrogenation and radical-mediated photocatalytic perfluoroalkylations. These polymeric radical systems open new avenues to design novel functional polymers for catalysis and photoelectrical chemistry.