Thiazolo-Thiazole Integrated Porous Organic Polymer (POP) as an Efficient Visible Light-Mediated Photocatalyst for Oxidation of Amines and Alkenes

We describe the development of an efficient, sustainable, and metal-free porous organic polymer (POP), i.e., TMeOBPTzTz, based on a thiazolo-thiazole (TzTz) scaffold as a robust heterogeneous photocatalyst for visible light-driven oxidation reactions. The polymer exhibits a high surface area (474 m2 g–1), permanent microporosity, excellent thermal stability, and broad optical absorption extending up to 700 nm with an optical band gap of 2.45 eV. These properties enable the efficient activation of molecular oxygen under mild conditions. It is shown that TMeOBPTzTz, as a dual-function heterogeneous photocatalyst, permits selective oxidation of amines to aldehydes/ketones and alkenes to aldehydes with a broad substrate scope, excellent functional group tolerance, and scalability to gram-scale synthesis. The catalyst also exhibits outstanding recyclability, maintaining its activity over multiple cycles without structural degradation, as confirmed by FT-IR and FESEM analyses. Mechanistic studies reveal that amine oxidation proceeds via a photoredox pathway involving the generation of a superoxide radical anion (O2–•) through single-electron transfer, while alkene oxidation follows an energy-transfer mechanism that produces singlet oxygen (1O2). The results demonstrate TMeOBPTzTz as a versatile, sustainable, and metal-free photocatalyst with considerable potential for green oxidative transformations in organic synthesis.