Amine-Derived Polymeric Frustrated Lewis Pair Networks and Catalysts

The addition of sufficient steric bulk to Lewis pairs precludes adduct formation while preserving latent reactivity. These species, known as frustrated Lewis pairs (FLPs), work cooperatively to activate and catalytically transform a variety of different substrates. Tethering these groups to a polymer backbone has created a field of stimuli-responsive materials which serve as recyclable catalysts. These original poly(FLPs) were built from phosphine and borane functionalized monomers. Polyamines remain unexplored as Lewis bases (LBs) in these systems, despite their relative synthetic tunability and air stability. Herein, we disclose the first use of polyamines in fully macromolecular poly(FLP) systems. A family of styrene-based functionalized copolymers with varying steric and electronic properties were synthesized via controlled radical polymerization. When combined with a suitable polymeric Lewis acid (LA), these polyamines activate small molecule cyclic ether substrates to generate poly(FLP) networks with varying rheological properties. Increased basicity of the polyamine not only enhances the covalent nature of these networks but also promotes the insertion of carbon dioxide to catalyze conversion to cyclic carbonates over three successive recovery and reuse cycles. With this first precedent for the application of polyamines in poly(FLP)-mediated catalysis, future directions focus on tuning poly(FLP) systems to activate more challenging substrates.