Postmodified Dual Functional UiO Sensor for Selective Detection of Ozone and Tandemly Derived Sensing of Al³

Development of highly sensitive and selective fluorescent sensors toward hazardous analytes represents great progress in fabricating sensing devices for practical applications. In this work, a highly selective sensor with dual functions has been fabricated via facile postmodification of the UiO-MOF. Butene modified salicylaldehyde is covalently linked to the UiO-66 scaffold via an efficient Schiff-base reaction, resulting in a highly fluorescent ozone sensor of UiO-66-butene. Ozonolysis of the terminal olefin followed by β-elimination could significantly quench the bright blue fluorescence of UiO-66-butene, and linear turn-off detection of ozone in the range of 0-100 μM is well established. The detection is highly sensitive and selective, and a detection limit of 73 nM was calculated. Remarkably, the ozonolysis afforded product could further act as a selective sensor for Al³⁺ via turn-on fluorescence with a detection limit of 142 nM, representing a second potential sensing function. The chemically selective sequential ozonolysis/β-elimination and remarkable dual functions offer the exclusive detection of ozone over other oxidative species as well as Al³⁺ over other cations following a tandem process, representing the first example of a direct MOF sensor for dual sensing of ozone and Al³⁺. This work demonstrates the potential of employing combinatorial principles for fabricating highly selective sensors, and postmodification of MOFs represents a promising facile strategy for developing various functional sensors.