Intramolecular Hydrogen-Bonding Catalyst/Initiator for Precise Synthesis of Polycarbonates and Copolymers with...

The development of efficient and selective catalytic methods for synthesizing well-defined polycarbonates and their copolymers represents a significant advancement toward sustainable polymer production. In this study, we report a series of innovative single-molecule hydrogen-bonding catalysts/initiators for the ring-opening polymerization (ROP) of cyclic carbonates, enabling rapid and precise synthesis of polycarbonates and their copolymers with polylactide. These catalysts uniquely facilitate simultaneous activation of both monomer and chain-end within a single molecular architecture, demonstrating superior activity compared to conventional multicomponent hydrogen-bonding initiating systems. Density functional theory (DFT) calculations reveal that alkyl substitution plays a critical role in enhancing catalytic activity for ROP by reducing the energy barrier relative to aryl-substituted analogues. The modular design of these catalysts allows for facile structural optimization and performance tuning. Notably, Cat. 1 exhibits high catalytic efficiency at 25 °C, producing polycarbonates with well-defined structures and high molecular weights (M_n up to 164.8 kDa, Ð of 1.37). We further demonstrate versatile copolymerization strategies: one-step copolymerization yields gradient polycarbonate-g-polylactide copolymers, whereas sequential monomer addition in one-pot reactions produces well-defined block polycarbonate-b-polylactide copolymers within minutes. These block copolymers exhibit high molecular weights (M_n up to 189.4 kDa, Ð of 1.37), precisely tunable thermal properties, and exceptional mechanical performance, highlighting their potential for advanced material applications.