To overcome the limitations of conventional conjugated porous organic polymer (CPOP) syntheses that require harsh conditions or metal catalysts and fail to introduce halogen substituents such as –Br and –I in a controlled manner, we present herein a strategically significant synthesis method based on bismuthene-catalyzed photoredox C–H arylation via in situ diazotization. This approach provides enhanced polymer chain growth with relatively high Mw (up to 322 kDa), ideal poly-dispersity, tunable optical properties (visible to NIR region), and enabling to access to a broad range of monomers with high tolerance for halogens. To gain deeper insight into the mechanism of C–C bond formation via bismuthene-catalyzed photoredox C–H arylation, control and scavenger experiments were performed. The results confirm that CPOP growth proceeds through a single-electron transfer pathway, forming linear or cross-linked networks. The resulting polymers exhibited efficient photocatalytic activity for the selective oxidation of styrene to benzaldehyde via singlet oxygen as the dominant reactive species, achieving > 99% conversion and selectivity under blue LED irradiation. Remarkably, halogen-containing CPOPs (–Br, –I) afforded higher yields and superior photocatalytic efficiency, attributed to the heavy-atom effect and defect generation, which collectively enhance visible-light absorption and charge separation.
Özer et al. (Tue,) studied this question.