Thiazolothiazole as a Multimonomer Adapting Organic Catalyst for Atom Transfer Radical Polymerization (ATRP) with Oxygen Tolerance

Light-controlled organic atom transfer radical polymerization (O-ATRP) has emerged as a mature and advanced method for synthesizing well-defined macromolecules. However, developing a high-performance, low-loading, and oxygen-tolerant O-ATRP catalyst system remains an urgent challenge. Herein, we developed a new O-ATRP catalyst based on 2,5-bis(4-pyridinium) thiazolo[5,4-<i>d</i>]thiazole. Such catalyst is facile to prepare and is available in both organic and aqueous phases through structural modifications. High molar extinction coefficient supports low catalyst loading (parts per million (ppm) level) and effective light control. As well as the conventional acrylate monomers, the catalyst showed fine compatibility with styrene monomers. Supramolecular interactions were applied to regulate its photochemical reaction pathway, resulting in a light-induced autocatalytic deoxygenation effect and achieving sunlight ATRP under air.