title: Boric-Acid-Functional Lanthanide Metal-Organic Frameworks for Selective Ratiometric Fluorescence Detection of Fluoride Ions.
abstract: Here, we report that boric acid is used to tune the optical properties of lanthanide metal-organic frameworks (LMOFs) for dual-fluorescence emission and improves the selectivity of LMOFs for the determination of F-ions. The LMOFs are prepared with 5-boronoisophthalic acid (5-bop) and Eu3+ions as the precursors. Emission mechanism study indicates that 5-bop is excited with UV photons to produce its triplet state, which then excites Eu3+ions for their red emission. This is the general story of the antenna effect, but electron-deficient boric acid decreases the energy transfer efficiency from the triplet state of 5-bop to Eu3+ions, so dual emission from both 5-bop and Eu3+ions is efficiently excited at the single excitation of 275 nm. Moreover, boric acid is used to identify fluoride specifically as a free accessible site. The ratiometric fluorescent detection of F-ions is validated with the dual emission at single excitation. The LMOFs are very monodisperse, so the determination of aqueous F-ions is easily achieved with high selectivity and a low detection limit (2 μM). For the first time, we reveal that rational selection of functional ligands can improve the sensing efficiency of LMOFs through tuning their optical property and enhancing the selectivity toward targets.
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology and Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University , Tianjin, 300071, China.
authors.forename: Zhong-Rui
authors.initials: ZR
authors.lastname: Yang
authors.affiliation: School of Public Health, North China University of Science and Technology , Tangshan 063000, Hebei, China.
authors.forename: Man-Man
authors.initials: MM
authors.lastname: Wang
authors.affiliation: School of Public Health, North China University of Science and Technology , Tangshan 063000, Hebei, China.
authors.forename: Xue-Sheng
authors.initials: XS
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Medicinal Chemical Biology and Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University , Tianjin, 300071, China.|Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin, 300071, China.
authors.forename: Xue-Bo
authors.identifier: 0000-0002-7954-163X
authors.initials: XB
authors.lastname: Yin