Phenazine‐based supramolecular photosensitizing assemblies: A “smart” selectivity control on catalytic activity of Pd(II) nanoparticles

Abstract

Photosensitizing supramolecular assemblies based on a phenazine derivative (PPA) have been developed, which show a strong affinity toward Pd²⁺ ions to generate supramolecular ensemble PPA@Pd nanoparticles (NPs). The PPA@Pd NPs catalyse the Suzuki cross-coupled reaction under mild conditions (aerial conditions, mixed aqueous media, and visible light radiations). Although PPA@Pd NPs exhibit a strong affinity for arylboronic acid and could catalyse homocoupling of arylboronic acid, the preference of PPA assemblies for aryl halide directed the course of reactions toward the formation of cross-coupled products. The electron-rich PPA assemblies not only facilitate the oxidative addition step through photoinduced electron transfer to Pd²⁺ ions but also bring the reactants closer to the catalytic sites by selective interactions with aryl halides in the presence of arylboronic acid under visible light irradiation. The efficiency of PPA@Pd NPs to catalyse the Suzuki cross-coupled reaction has been demonstrated for the synthesis of unsymmetrically substituted terphenyl derivatives.