Dynamic Linkage Microregulation at Atomic Nodes in Heptazine‐Based Polymeric Networks for Enhanced Photocatalytic Baeyer‐Villiger Oxidation

Abstract In pursuit of conventional harsh reaction conditions, production of industrially important precursor of poly( ɛ ‐caprolactone) via Baeyer‐Villiger oxidation challenged its environmental viability. Thus, development of reliable, cost‐effective, and sustainable catalytic system always remains a key challenge. In this context, metal‐free heptazine mesoporous polymeric networks are strategically designed to drive Baeyer‐Villiger oxidation under ambient conditions using O 2 /benzaldehyde system in visible light. Thus, herein, unsaturated bonds within heptazine‐based systems are deliberately modulated, inducing polarized charge distribution within the structures, elucidated through DFT analysis. This narrows the bandgap, tailoring the chemical, electronic, and photocatalytic properties of the systems. For this purpose, HMP‐AZO and HMP‐STB, incorporating azo and stilbene‐based electron‐donor moieties, respectively, are developed, and their photocatalytic oxidation capabilities are compared for Baeyer‐Villiger oxidation reaction to investigate their structure‐property‐activity relationship. Remarkably, HMP‐STB exhibited superior photocatalytic performance, achieving 87% cyclohexanone conversion to ɛ ‐caprolactone along with 4.12 mmol g −1 of H 2 O 2 in 12 h, significantly outperforming HMP‐AZO. Extensive investigations elucidated the cooperative role of reactive oxygen species and photocatalyst through in situ EPR, PL, Raman, HR‐MS, KPFM, and DFT studies, thus unravelling the extensive mechanistic understanding for photocatalytic Baeyer‐Villiger oxidation. Overall, this report paves a new approach to caprolactone production through a cascade reaction pathway.