Incorporation of thiazolothiazole fluorophores into a MOF structure: A highly luminescent Zn(II)-based MOF as a selective and reversible sensor for Cr2O72− and MnO4− anions

Abstract A highly luminescent ZnII-MOF, [Zn2 (TzTz)2(BDC)2]·2DMF, TzTz ​= ​2,5-di (4-pyridyl)thiazolo [ (Liu et al., 2019; Shen et al., 2018) [4,5]-d]thiazole and BDC ​= ​terephthalic acid), has been solvothermally assembled and fully characterized by single crystal X-ray crystallography, elemental analysis, FT-IR spectroscopy and X-ray diffraction (XRD). This transition-metal based luminescent MOF exhibits strong blue emission while capable as a selective sensor for detection of anions. Only trace amounts of fluorescent MOF can act as a highly selective and recyclable luminescent probe for the quantitative detection of CrVI and MnVII (Cr2O72−, MnO4−) anions in aqueous solutions with large quenching constants (9 ​× ​107 ​M−1 and 4.8 ​× ​103 ​M−1 for Cr2O72−and MnO4−) via an energy-transfer mechanism. The first sensing study of a TzTz-functionalized MOF material demonstrates the highest sensing ability among the previously reported fluorescent MOFs with detection limits for Cr2O72− and MnO4− ions in drinking water as low as 4 ​μM (100 ​ppb).