An amino-decorated dual-functional metal-organic framework for highly selective sensing of Cr(III) and Cr(VI) ions and detection of nitroaromatic explosives

A 3D Zn(II)-based metal-organic framework, [Zn-2(TPOM)(NH2-BDC)(2)]center dot 4H(2)O (NH2-Zn-MOF, TPOM = tetrakis(4-pyridyloxymethylene)methane and NH2-BDC = 2-aminoterephthalic acid), was successfully achieved via a hydrothermal reaction. The framework adopts a (4,2)-connected 3D network, with the Schlafli symbol {6(2)center dot 8(4)}. This complex exhibits strong luminescence emission, which is selectively sensitive to Cr(III) and Cr(VI) ions. More importantly, the fluorescence explorations indicated that it represents the first example of MOF-based fluorescent probes for detecting Cr(III) through a fluorescence enhancement mechanism. In addition, it also shows highly selective and sensitive detection of electron-deficient nitroaromatic compounds through fluorescence quenching. These properties make the NH2-Zn-MOF a potential luminescence sensor for selectively detecting these chemicals.