Acyl hydrazone-based supramolecular polymer for ultrasensitive detection of Fe3+, Pd2+, H2PO4- and its application for Suzuki coupling reactions

A novel acylhydrazide-based gelator (BE) was successfully built without the use of traditional fluorescent groups. Surprisingly, in 1,2-propanediol, the BE can further self-assemble into a stable supramolecular gel (OBE) and display significant blue-white aggregation-induced enhanced emission (AIEE). Interestingly, based on the excellent coordination capacity of acyl hydrazone bonds, the OBE demonstrated a sensitive response to Pd2+ and Fe3+, with corresponding lowest limits of detection of 21.8 and 37.3 ppb, respectively. More interesting, H2PO4- could only be constantly recognized by the Pd-OBE (Pd2+ coordinated with OBE). Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), density functional theory (DFT) and rheological measurements, the self-assembly process of OBE, and the ion recognition sensing mechanism were extensively examined. Moreover, xerogel OBE as supporter, a novel heterogeneous catalyst Pd/OBE is prepared. The catalyst displays outstanding activity and stability for Suzuki coupling reactions in water. It can be easily reused for at least five runs with no decrease in the catalytic activity.