A Dihydrotetrazine-Functionalized Metal-Organic Framework as a Highly Selective Luminescent Host-Guest Sensor for Detection of 2,4,6-Trinitrophenol

Pore decoration of metal-organic frameworks(MOFs) with functional groups is a useful strategy to attain high selectivity toward specific analytes, especially in the presence ofinterfering molecules with similar structures and energy levels ,through selective host-guest interactions. In this work, we applieda dihydrotetrazine-decorated MOF, TMU-34, with the formula[Zn(OBA)(H2DPT)0.5]nmiddotDMF, where H2OBA is 4,4 '-oxybis-(benzoic acid) and H2DPT is 3,6-bis(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine, for the highly selective detection of phenolicNACs, especially TNP (94% quenching efficiency, detection limit8.1x10-6M,KSV= 182663 mol L-1), in the presence of othersubstituted NACs especially-NH2-substituted NACs. Investigations reveal that the quenching mechanism is dominated byphotoinduced MOF-to-TNP electron transfer through possible hydrogen-bonding interactions between the phenolic hydroxyl groupof TNP and dihydrotetrazine functions of TMU-34. Despite extensive publications on the detection of TNP in the presence of otherNACs, the significance of this work will be elucidated if attention is paid to the fact that TMU-34 is among the rare and highlyselective MOF-based TNP sensors in the presence of-NH2-substituted NACs as the serious interferers