Photocontrolled Synthesis of n-Type Conjugated Polymers

Angew Chem Int Ed Engl. 2020 Apr 6;59(15):6062-6067. doi: 10.1002/anie.201915819. Epub 2020 Feb 18.

Abstract

Current approaches to synthesize π-conjugated polymers (CPs) are dominated by thermally driven, transition-metal-mediated reactions. Herein we show that electron-deficient Grignard monomers readily polymerize under visible-light irradiation at room temperature in the absence of a catalyst. The product distribution can be tuned by the wavelength of irradiation based on the absorption of the polymer. Conversion studies are consistent with an uncontrolled chain-growth process; correspondingly, chain extension produces all-conjugated n-type block copolymers. Preliminary results demonstrate that the polymerization can be expanded to donor-acceptor alternating copolymers. We anticipate that this method can serve as a platform to access new architectures of n-type CPs without the need for transition-metal catalysis.

Keywords: Grignard compounds; conjugated polymers; photopolymerization; transition-metal-free chemistry.