An Olefin-based, Fluorescent Covalent Organic Framework for Selective Sensing of Aromatic Amines

Owing to various chemical structures and different basicity of amines, a fluorescent probe that could distinguish aromatic and aliphatic amines is highly desirable for practical applications. Herein, an olefin-based, fluorescent COF (COF-Py-AN) with unique π-electron deficient groups was synthesized, which was a functionalized platform to realize sensing of π electron-rich aromatic amines. COF-Py-AN displayed fluorescence quenching in the presence of aromatic amines like aniline, with excellent selectivity against a variety of aromatic molecules, and the detection limit of COF-Py-AN toward aniline was as low as 1.29 μM. More importantly, COF-Py-AN could realize discriminating between aromatic and aliphatic amines. Furthermore, density functional theory calculations showed that the photoinduced electron transfer mechanism contributes to fluorescence sensing. This is the first example of olefin-based fluorescent COF materials for selective sensing of aromatic amines.