Bifunctional Luminescent Rare Earth Metal–Organic Frameworks for Highly Sensing Fe 3+ Ions and TNP

Two isostructural rare earth metal–organic frameworks, namely [Re 2 (BBTC)(DMF) 5 Cl 2 ]·2DMF·H 2 O [BBTC 4– = 1,1'-butadiynebenzene-3,3',5,5'-tetracarboxylate, Re = Y ( 1 ) and Ho ( 2 )], have been prepared via solvothermal reaction. Single crystal X − ray analyses reveal that complexes 1 and 2 both crystallize in the P 2 1 /m space group. Topological analyses suggest that these frameworks possess the same two–dimensional (2D) (4,4)-connected networks. Notably, the emission spectrum reveals the fluorescence of complex 1 is mainly from the ligands to ligands charge transfer transition. Further investigation indicates that complex 1 can act as a fluorescent sensor for highly sensitive and selective detection of Fe 3+ and 2,4,6-trinitrophenol (TNP) in MeCN solution, the quenching constants ( K sv ) are 1.45 × 10 5 M −1 for Fe 3+ and 4.08 × 10 4 M −1 for TNP, with the detection limit (LOD) of 0.12 µM for Fe 3+ and 0.52 µM for TNP. Furthermore, the possible sensing mechanisms of complex 1 as bifunctional sensors have been studied based on experiments. Graphical Abstract Two isostructural rare earth metal–organic frameworks based on 1, 1'−butadiynebenzene−3, 3’, 5, 5’−tetracarboxylate ligand were synthesized and structurally characterized in detail, and complex 1 is promising bifunctional luminescent probe for highly sensitive and selective sensing Fe 3+ ions and TNP through luminescence quenching effect, complex 1 also exhibits good recyclability for detecting Fe 3+ ions and TNP. The quenching mechanisms were studied as well.