Two Ag(I) organic frameworks as multi-responsive fluorescent sensors: Synthesis, structures and sensing of Cr2O72− ions, benzaldehyde and levofloxacin in water

Two new metal-organic frameworks (MOFs), [Ag(H2BTA)0.5(L1)0.5]n (1) and {[Ag2(BTA)0.5(L2)]·0.5H2O}n (2) were hydrothermally synthesized (L1 ​= ​1,4-bis(1-(pyridin-4-ylmethyl)-1H-benzo[d]imidazole-2-yl)butane, L2 ​= ​1,4-bis(1-(pyridin-4-ylmethyl)-1H-benzo[d]imidazole-2-yl)hexane H4BTA ​= ​1,2,4,5-benzenetetracarboxylic acid) and characterized by physico-chemical and spectroscopic methods. 1 manifests an unprecedented 3D gwg topological network. 2 plays an unusual 3,4,4L65 2D sheet with a 3-node (3,4,4)-connected framework. Both 1 and 2 can serve as multi-responsive fluorescence sensors for detection of Cr2O72− ions, benzaldehyde and levofloxacin (LEV) with high sensitivity and selectivity. The sensing mechanism of two MOFs is further discussed.