title: A flexible Eu(III)-based metal-organic framework: turn-off luminescent sensor for the detection of Fe(III) and picric acid.
abstract: A metal-organic framework (MOF) {[Eu2(MFDA)2(HCOO)2(H2O)6]·H2O}n (1) (H2MFDA = 9,9-dimethylfluorene-2,7-dicarboxylic acid) has been solvothermally synthesized and structurally characterized. 1 possesses the three-dimensional pcu type rod-packing structure with one-dimensional rhombic channels. The framework of 1 can reversibly shrink/swell along the c axis upon partial/full release of the water molecules. Correspondingly, the rhombic channels become narrow/large and 1 transforms to narrow-pore 1a/large-pore 1b. 1, 1a and 1b have almost the same excitation and emission spectra with the strong characteristic red-light-emission of Eu(III). A high photoluminescence quantum yield of 77% and long luminescence lifetime of around 1.1 ms was observed for 1. The potential of 1b for Fe(3+) ions and PA sensing was studied in DMF through the luminescence quenching experiments, which show 1b is a potential turn-off luminescent sensory material for the selective detection of Fe(3+) ions and PA with detection limits of around 10(-7) M for both of them. The fluorescence quenching mechanism for Fe(3+) ions and PA was also investigated.
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), Nanjing, 210023, PR China. iamxhzhou@njupt.edu.cn
authors.forename: Xin-Hui
authors.initials: XH
authors.lastname: Zhou
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Hong-Hui
authors.initials: HH
authors.lastname: Li
authors.forename: Ao
authors.initials: A
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Huang