Dual-Emitting Dye@MOF Composite as a Self-Calibrating Sensor for 2,4,6-Trinitrophenol

An
anionic metal–organic framework (MOF) {(NH2Me2)­[Zn3(μ3-OH)­(tpt)­(TZB)3]­(DMF)12}n (1, tpt = 2,4,6-tri­(4-pyridyl)-1,3,5-triazine, H2TZB = 4-(1H-tetrazol-5-yl)­benzoic acid and DMF = N,N-dimethylformamide), with both nanosized cages
and partitions, has been solvothermally synthesized, which can serve
as a crystalline vessel to encapsulate the fluorescent dye rhodamine
6G (Rh6G) via a “bottle around ship” approach. As a result, the
obtained dye@MOF composite system features a blue emission of the
ligand at 373 nm and a red emission of Rh6G at 570 nm when dispersed
in solution, which could be used for decoding the trace amount of
2,4,6-trinitrophenol (TNP) by referring the peak-height ratio of each
emission, even in coexistence with other potentially competitive nitroaromatic
analytes. Furthermore, the observed fluorescence responses of the
composite toward TNP are highly stable and reversible after recycling
experiments. To the best of our knowledge, this is the first example
of an MOF-implicated self-calibrated sensor for TNP detection.