A Highly Efficient Supramolecular Polymer-Based Singlet Oxygen Generator for Photocatalytic Minisci Alkylation

Supramolecular polymers, with their specific functional units and structures, can effectively enhance the absorption and utilization of light energy, thereby facilitating more efficient photocatalytic organic reactions. In the present work, we constructed a supramolecular polymer consisting of benzothiazole derivatives (BTBP) and cucurbit[8]uril (CB[8]). The BTBP monomer, known for its unique chemical structure and properties, has been found to exhibit a remarkable capability in generating singlet oxygen (¹O₂). As a result of the constraining impact of the macrocyclic molecule, the inclusion of CB[8] resulted in an effective enhancement in the ability to generate ¹O₂ while forming supramolecular polymer BTBP-CB[8]. When evaluating the quantum yield of ¹O₂ using Rose Bengal (RB) as a reference photosensitizer (75% in water), BTBP-CB[8] demonstrated an enhanced ¹O₂ quantum yield compared to BTBP, with an impressive yield of 152.4%, demonstrating that the formation of supramolecular polymer contributes to its ability to generate ¹O₂. Subsequently, BTBP-CB[8], a highly efficient ¹O₂ generator, was employed for the photocatalytic Minisci alkylation reaction, resulting in an impressive reaction yield of up to 89%. The supramolecular polymer strategies employed in the construction of photocatalytic systems have exhibited remarkable efficacy in the production of ¹O₂, underscoring their immense prospects in photocatalysis.