The ligands (3,6-di(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine), H2DPT, as a pillar spacer and (4,4'-oxybis(benzoic acid)), H2OBA, as a dicarboxylate linker were used to develop a dihydro-tetrazine functionalized pillared-MOF, [Zn(OBA)(H2DPT)0.5].DMF (TMU-34) as functionally convertible stimuli responsive MOF-based Sensor. Sonochemically synthesized powder of TMU-34 was employed in sensing of volatile organic compounds (VOCs). The results show that TMU-34 can act as a solid state naked-eye visual chemosensor for detection of chloroform in liquid and gas phases. TMU-34 as a chemo-switchable MOF, undergoes a significant color change from yellow to pink through reversible dynamic conversion of dihydro-tetrazine to tetrazine upon exposure to chloroform in the presence of other VOCs with a fast response. Deposit diversity in colorimetric MOF-based sensors which show a wide range of color changing in the presence of different analytes, TMU-34 undergoes color changing only in presence of chloroform. The proposed mechanism through color changing has been discussed and characterized by UV-visible (UV-vis) and 1HNMR spectroscopies. These observations reveal that TMU-34 can act as one of the most promising candidates in highly selective and sensitive detection of chloroform.
