Bis-Pyridine-Based Organogel with AIE Effect and Sensing Performance towards Hg(2+)

A novel gelator (1) based on a bis-pyridine derivative was designed and synthesized, which could form stable gels in methanol, ethanol, acetonitrile, ethyl acetate, DMF/H(2)O (4/1, v/v) and DMSO/H(2)O (4/1, v/v). The self-assembly process of gelator 1 was studied by field emission scanning electron microscopy (FESEM), UV–vis absorption spectroscopy, fluorescence emission spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction and a water contact angle experiment. Gelator 1 exhibited obvious AIE behavior. On the base of its AIE, the gel of 1 could detect Hg(2+), which resulted in fluorescence quenching and a gel–sol transition. (1)H NMR titration experiments with Hg(2+) revealed that the metal coordination interaction induced the fluorescence quenching and the breakdown of the noncovalent interaction in the gel system. This research provides a new molecular mode for designing a functional self-assembly gel system.