Stable Luminescent Metal-Organic Frameworks as Dual-Functional Materials To Encapsulate Ln3+ Ions for White-Light Emission and To Detect Nitroaromatic Explosives

A stable porous carbazole-based luminescent metalorganic framework, NENU-522, was successfully constructed. It is extremely stable in air and acidic/basic aqueous solutions, which provides the strategy for luminescent material encapsulation of Ln(3+) ions with tunable luminescence for application in light emission. More importantly, Ln(3+)@NENU-522 can emit white light by encapsulating different molar ratios of Eu3+ and Tb3+ ions. Additionally, Tb3+@NENU-522 is found to be useful as a fluorescent indicator for the qualitative and quantitative detection of nitroaromatic explosives with different numbers of -NO2 groups, and the concentrations of complete quenching are about 2000, 1000, and 80 ppm for nitrobenzene, 1,3-dinitrobenzene, and 2,4,6-trinitrophenol, respectively. Meanwhile, Tb3+@NENU-522 displays high selectivity and recyclability in the detection of nitroaromatic explosives.