Metal-Free Triazine-Based Polymeric Network for Solar-to-Chemical Conversion: An Insight into the Aza-Henry Reaction

Abstract

Solar light-assisted chemical transformation is one of the most amicable pathways to achieving sustainability. With this aim, herein, we have developed a metal-free triazine-based donor–acceptor polymeric network (TMP-TAPA) as a photocatalyst for cross-dehydrogenative coupling reaction with an insight toward the aza-Henry reaction. Various characterization techniques including N2 physisorption, PXRD, FTIR, and solid-state NMR spectroscopy have been adopted to characterize the synthesized TMP-TAPA photocatalyst. The BET method demonstrated the existence of microporosity with a surface area of 296 m2/g in TMP-TAPA. Photocatalytic experiments have been performed under a 15 W table lamp, showing a conversion rate of 70% with >99% selectivity in the cross-dehydrogenative coupling reaction. The mechanistic pathway of the reaction has been thoroughly investigated, which was further corroborated by controlled studies in addition to scavenger and substrate studies. The proposed mechanistic pathway showed the importance of singlet oxygen species in the photocatalyzed cross-dehydrogenative aza-Henry reaction.