Perylene Bisimide–Based Porous Organic Polymer (POP) as a Dual‐Function Heterogeneous Photocatalyst for Energy and Electron Transfer: Oxidative Esterification of Aldehydes and α‐Cyanation of Tetrahydroisoquinolines

Abstract

Leveraging the exceptional optical and redox properties of perylene bisimides (PBIs), a unique class of π‐conjugated chromophores, we have synthesized a porous organic polymer (POP), PBI‐TMBP , by Williamson etherification. Owing to its strong absorption in the visible region, PBI‐TMBP serves as an efficient heterogeneous photocatalyst for visible light‐driven esterification of aldehydes and α‐cyanation of tetrahydroisoquinolines under an oxygen atmosphere. Mechanistic studies reveal that PBI‐TMBP enables, upon photoirradiation, two distinct pathways: energy transfer and electron transfer, resulting in the formation of reactive oxygen species (ROS), namely, singlet oxygen ( 1 O 2 ) and superoxide radical (O 2 •– ); these species are responsible for driving the oxidative transformations efficiently. Remarkably, subtle structural constraints exerted by covalent polymerization in conjunction with the solid‐state medium promote intersystem crossing (ISC) to the triplet state, which has been otherwise observed only in structurally unique PBI derivatives. It is shown that PBI‐TMBP displays excellent reusability over multiple catalytic cycles without any noticeable loss in activity or structural integrity. Overall, this work demonstrates the development of a robust, dual‐function visible‐light photocatalytic POP, synthesized via bottom‐up covalent polymerization of rationally designed PBI monomer, and its application to efficiently carry out two distinct classes of organic reactions mediated by singlet oxygen and superoxide.