Supramolecular Ensemble of a TICT-AIEE Active Pyrazine Derivative and CuO NPs: A Potential Photocatalytic System for Sonogashira Couplings

The donor acceptor system 4 having pyrazine scaffold as an acceptor moiety coupled to donor amino groups through rotatable phenyl rings has been synthesized, which formed aggregates in aqueous media, exhibited copper induced restriction to intramolecular rotation, and served as a not quenched probe for the detection of copper(II) ions. During this process, the aggregates of derivative 4 acted as reactors and stabilizers for the generation of CuO NPs and themselves became oxidized to form polyamine derivative 6. Interestingly, the oxidized species 6 in combination with copper oxide nanoparticles served as light-harvesting antennas and exhibited excellent photocatalytic efficiency in Sonogashira coupling under mild and eco-friendly conditions (room temperature, aqueous media, aerial conditions, and visible light irradiation).