Organocatalytic Atom Transfer Radical Polymerization with Light and pH Dual-Gated Regulation

To improve the control and precision in polymer synthesis, the development of polymerization with logical control by multiple stimuli has attracted considerable attention in recent years. Herein, we describe the first introduction of a dual regulation by light and pH to organocatalytic atom transfer radical polymerization (O-ATRP), which features its mild conditions, visible light irradiation, transition metal-free products, and excellent on/off control by both pH and light. 1,1-Binaphthol (BINOL) was successfully identified as a new class of pH-responsive photoredox catalysts for O-ATRP, and show readily tunable photophysical properties and highly reversible chromic shift of maximum absorption (up to 60 nm) by very mild pH-mediation (pH 5/7). Moreover, the unique features of BINOL also inspires the discovery of simple phenols like naphthol and pyrenol that could also serve as effective O-ATRP catalysts upon basic mediation and afford high catalytic efficiency and good control on polymerization. We reckon the discovery of pH-responsive organic photocatalysts and the logic-controlled polymerization with will represent a first step toward the synthesis of polymers that mimics stimuli-responsive synthesis in nature.