Tailoring of Hetero–oligophenylene Stabilized Nanohybrid Materials: Potential Tandem Photo-Promoted Systems for C–C and C–X Bond Formation Reactions via C-H Activation

Supramolecular assemblies of the hetero-oligophenylene derivative 3 served as reactors for the facile synthesis of ZnO and Pd NPs in mixed aqueous media. Unprecendentally, these assemblies provided a common platform for the generation of bimetallic Pd-ZnO nanohybrid materials in aqueous media which served as efficient catalytic systems in C−C/C−X bond forming reactions. The freshly prepared zinc oxide nanoparticles showed high efficiency in (i) single pot three (in situ five) component reactions for the synthesis of tetrahydropyridine derivatives ii) photo-promoted synthesis of propargylamines via A³-coupling reaction. On the other hand, freshly prepared bimetallic Pd-ZnO nanohybrid materials enabled efficient harvesting of visible light radiation to catalyze biaryl coupling and “green” Sonogashira coupling in aqueous media. Additionally, ZnO NPs and Pd NPs in combination with bimetallic Pd-ZnO nanohybrid materials efficiently photocatalyzed the “one-pot two-step reactions” comprising Sonogashira cross coupling, reduction and three component reaction for the synthesis of tetrahydropyridine derivative in good yield.