Two robust dual-functional Cd(II) MOFs as luminescent sensors for quantitatively detection of nitrofurazone and Fe3+ ions

Developing luminescent sensors based metal organic framework (MOFs) for the detection of antibiotics and metal ions is still a major challenge. The two new ternary Cd(II)-based MOFs, namely, {[Cd(BTA)0.5(L)0.5]n} (1) and {[Cd(HBTC)(L)]n} (2) (H4BTA = 1,2,4,5-benzenetetracarboxylic acid, H3BTC = 1,2,4-benzenetricarboxylic acid, and L = 1,4-bis(2-((1H-imidazol-1-yl)methyl)-1H-benzo[d]imidazol-1-yl)but‑2-ene), were hydrothermally synthesized and characterized. 1 displays a 4,4-connected sqc183 topological framework with point symbol {42.84}, while 2 exhibits a 4,5-connected sqc65 framework with point symbol {42.64}{43.67}2. Both 1 and 2 display remarkable luminescence emission and enable selective detection of NFZ and Fe3+ ions with high anti-interference ability as well as excellent thermal and pH stability. The limits of detection (LOD) of 1 and 2 for nitrofurazone (NFZ) are 4.5 × 10−7 mol·L−1 and 9.0 × 10−7 mol·L−1, respectively. The LOD toward Fe3+ for 1 is 1.4 × 10−5 mol·L−1, for 2 is 6.2 × 10−6 mol·L−1. To the best of our knowledge, this is the first example of MOFs bearing L ligands as dual-functional luminescent sensors for sensing NFZ and Fe3+ ions. In addition, the mechanism of luminescence quenching was investigated.