<i>ortho</i>-Terphenylene Viologens with Through-Space Conjugation for Enhanced Photocatalytic Oxidative Coupling and Hydrogen Evolution
Ben Lin He, Sikun Zhang, Yueyan Zhang, Guoping Li, Bingjie Zhang, Wenqiang Ma, Bin Rao, Ruitong Song, Lei Zhang, Yanfeng Zhang, Gang He
Abstract
A series of novel ortho-terphenylene viologen derivatives (o-TPV2+) with through-space conjugation (TSC) via the combination of ortho-terphenylene skeletons with viologen structure is reported. Their optoelectronic properties can be adjusted by N-arylation or N-alkylation reactions. Compared with other viologen derivatives, o-TPV2+ not only exhibits strong photoluminescence but also retards the charge recombination process and stabilizes the diradical state without forming a quinoid structure due to the special TSC effect. Based on their special redox characteristics, o-TPV2+ was applied to the photocatalytic oxidative coupling of benzylamine with 96% yield. In addition, pTA-o-TPV2+ (tethered with p-toluic acid)-modified g-C3N4 was used for visible-light-driven hydrogen production for the first time, exceeding 15 times the rate over unmodified g-C3N4.