Experimentation and Theoretic Calculation of a BODIPY Sensor Based on Photoinduced Electron Transfer for Ions Detection

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• 作者：Hua Lu ; ShuShu Zhang ; HanZhuang Liu ; YanWei Wang ; Zhen Shen ; ChunGen Liu ; XiaoZeng You
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：December 24, 2009
• 年：2009
• 卷：113
• 期：51
• 页码：14081-14086
• 全文大小：290K
• 年卷期：v.113,no.51(December 24, 2009)
• ISSN：1520-5215

文摘

A boron-dipyrromethene (BODIPY)-based fluorescence probe with a N,N′-(pyridine-2, 6-diylbis(methylene))-dianiline substituent (1) has been prepared by condensation of 2,6-pyridinedicarboxaldehyde with 8-(4-amino)-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene and reduction by NaBH₄. The sensing properties of compound 1 toward various metal ions are investigated via fluorometric titration in methanol, which show highly selective fluorescent turn-on response in the presence of Hg²⁺ over the other metal ions, such as Li⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, Pb²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Ag⁺, and Mn²⁺. Computational approach has been carried out to investigate the mechanism why compound 1 provides different fluorescent signal for Hg²⁺ and other ions. Theoretic calculations of the energy levels show that the quenching of the bright green fluorescence of boradiazaindacene fluorophore is due to the reductive photoinduced electron transfer (PET) from the aniline subunit to the excited state of BODIPY fluorophore. In metal complexes, the frontier molecular orbital energy levels changes greatly. Binding Zn²⁺ or Cd²⁺ ion leads to significant decreasing of both the HOMO and LUMO energy levels of the receptor, thus inhibit the reductive PET process, whereas an oxidative PET from the excited state fluorophore to the receptor occurs, vice versa, which also quenches the fluorescence. However, for 1-Hg²⁺ complex, both the reductive and oxidative PETs are prohibited; therefore, strong fluorescence emission from the fluorophore can be observed experimentally. The agreement of the experimental results and theoretic calculations suggests that our calculation method can be applicable as guidance for the design of new chemosensors for other metal ions.