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

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 Al 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 Al over other cations following a tandem process, representing the first example of a direct MOF sensor for dual sensing of ozone and Al. 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.