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 Pd 2+ 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 Pd 2+ 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 crosscoupled reaction has been demonstrated for the synthesis of unsymmetrically substituted terphenyl derivatives.

The effect of substituents on the aggregation-induced emission of 9,10-phenanthraquinone-hydrazones

“…S19a and S24a, ESI†). 38 However, compounds 2–5 behave oppositely; blue-shifted absorption bands emerged upon increasing the water fraction, indicating the formation of H-aggregates (Fig. S20a–S23a, ESI†).…”

Pyrazine Derivative as Supramolecular Host for Immobilization of Palladium Nanoparticles for Efficient Suzuki Coupling

“…The strategy worked well for the gram scale synthesis, preparation of p ‐substituted terphenyls and for the preparation of fluorescent pyrazine derivatives ( PYZ ‐ TA ‐ TPh and PYZ ‐ TA ‐ TAl ) through Suzuki coupling. Recently, we reported the development of in situ generated PPA@Pd NPs which exhibited high catalytic efficiency in Suzuki coupling reaction [29] . The PPA@Pd NPs could be recycled up to seven cycle with the decrease in the yield of the final product.…”

“…Recently, we reported the development of in situ generated PPA@Pd NPs which exhibited high catalytic efficiency in Suzuki coupling reaction. [29] The PPA@Pd NPs could be recycled up to seven cycle with the decrease in the yield of the final product. Nonetheless for setting up the catalytic reaction, prior formation of self-assembled catalyst in a solution phase is a perquisite.…”

Cobalt-Centered Supramolecular Nanoensemble for Regulated Aerobic Oxidation of Alcohols and “One-Pot” Synthesis of Quinazolin-4(3H)-ones

“…Our research work involves the development of photocatalytic ensembles consisting of supramolecular photosensitizing host assemblies as light-harvesting antenna/stabilizers and catalytically active metallic species to perform organic transformations under green conditions . Very recently, we reported supramolecular catalytic ensemble PPA@Pd which showed high efficiency in C–C bond formation . In continuation of this work, we were then interested in the development of a cobalt-centered supramolecular photocatalytic ensemble for regulated aerobic oxidation of alcohols under mild reaction conditions.…”