An -OH group functionalized MOF for ratiometric Fe3+ sensing

作者:Xu, Hui*; Dong, Yingying; Wu, Yuhang; Ren, Wenjing; Zhao, Tao; Wang, Shunli; Gao, Junkuo*
来源:Journal of Solid State Chemistry, 2018, 258: 441-446.
DOI:10.1016/j.jssc.2017.11.013

摘要

Iron is one of the most important elements in the biochemical processes in all living system, both deficiency or excess of iron will lead to metabolism disorder diseases. However, Fe3+ is one of the most efficient fluorescence quenchers among the transition-metal ions because of its paramagnetic nature. The realization of Fe3+ ratiometric and self-calibrated fluorescent sensor is highly-challenging. We synthesized a novel luminescent -OH functionalized EuOHBDC (Eu-2(OH-BDC)(3), OH-BDC=2-hydroxyterephthalic acid) by hydrothermal reaction and in situ ligand synthesis, and used it as a rare ratiomatric luminescent sensor for Fe3+ ions. The -OH functional group facilitates both electron transfer and binding interaction between EuOHBDC and Fe3+, which lead to luminescent quenching of ligand-based emission while enhancement of a new peak emission, and thus enables ratiometric detection of Fe3+. The relative fluorescent intensity ratio (I-375/I-427) increased linearly with increasing Fe3+ concentration in the 10-50 mu M range with 1.17 mu M (65 ppb) detection limit. The EuOHBDC also shows excellent selectivity towards different metal ions, particularly can discriminate Fe3+ and Fe2+ through different luminescent responses. This result clearly demonstrates the superiority of -OH functionalized MOF for Fe3+ detection, which can contribute to develop high performance luminescent probe for detection of metal ions in environmental and biomedical applications.