Tailoring Vinylene‐Linked Triazine Covalent Organic Frameworks for Efficient Photocatalytic Selective Oxidation of Organic Sulfides

ABSTRACT

Covalent organic frameworks (COFs) have emerged as a highly promising platform for photocatalytic reactions because their electronic structures can be tailored through the rational selection of linkages and building blocks. Here, by the condensation of 2,4,6‐trimethyl‐1,3,5‐triazine (TMT) with 2,4,6‐tris(4‐((4‐formylphenyl)ethynyl)phenyl)‐1,3,5‐triazine (TPEPT) and 2,4,6‐tris(4′‐formyl‐biphenyl‐4‐yl)‐1,3,5‐triazine (TBPT), respectively, two vinylene‐linked triazine COFs, TMT‐TPEPT‐COF and TMT‐TBPT‐COF, are rationally designed and constructed. Compared to TMT‐TBPT‐COF, acetylene insertion enhances the backbone coplanarity of TMT‐TPEPT‐COF, reducing the dihedral angle from 33.4° to 14.0°. Theoretical calculations reveal a more spatially polarized frontier‐orbital distribution in TMT‐TPEPT‐COF, with the lowest unoccupied molecular orbital preferentially localized on the triazine units. TMT‐TPEPT‐COF shows a narrower band gap, broader visible‐light absorption, faster charge separation and migration than TMT‐TBPT‐COF. Consequently, TMT‐TPEPT‐COF exhibits superior activity for the efficient photocatalytic selective oxidation of organic sulfides and the detoxification of a sulfur‐mustard gas simulant 2‐chloroethyl ethyl sulfide with oxygen. Superoxide is pinpointed as the key reactive oxygen species driving the photocatalytic oxidation. Collectively, this work establishes π‐conjugation engineering as a sustainable means to enhance COF electron transfer for solar‐driven photocatalytic reactions.