Luminescent Cd(II) metal-organic frameworks with anthracene nitrogen-containing organic ligands as novel multifunctional chemosensors for the detection of picric acid, pesticides, and ferric ions

Four novel luminescent metal-organic frameworks (F1, F2, F3, F4), containing cadmium ions, carboxylic acid ligands, and the anthracene nitrogen-containing organic ligand (9,10-bis(N-benzimidazolyl)-anthracene, L) were synthesized by a one-pot synthesis under solvothermal conditions. F2, F3, and F4 show porous three-dimensional (3D) structures and F1 is characterized by a 2-fold interpenetrating 3D structure. Fluorescence sensing experiments reveal that F2, F3, and F4 are cable of multifunctional chemosensors to detect picric acid (TNP), pesticides as well as ferric ions with high sensitivity, selectivity, and good recoverability. Furthermore, theoretical studies demonstrate that the quenching phenomenon may be well explained by the mechanism of competitive absorption of excitation energy, electron transfer as well as the resonance energy transfer.