Two metal-organic frameworks based on phenylenediacetate and N,N′-Bis-pyridin-3-ylmethylene-hydrazine used as multi-responsive luminescent sensors for Fe3+, CrO42- and Cr2O72- in aqueous solution

Two novel metal-organic frameworks (MOFs), namely, [Ni(3-bpmh)(HEA)center dot 2H(2)O](n) (1) and [Zn(3-bpmh)(HEA)center dot H2O](n) (2) (3-bpmh=1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, o-H(2)HEA=1,2-phenylenediacetic acid), respectively, were hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy and thermogravimetric analysis. Single crystal structures revealed that 1 and 2 were two-dimensional structure and two-dimensional (4,4)-topological layer structure respectively. In addition, compound 2 had a selective sensing effect on ions. Therefore, it was possible to detect Cr2O72-, CrO42- and Fe3+ ions by fluorescence quenching.