| Autor: |
Lee, Yelim, Kim, Joon Rae, Lee, Eunji |
| Předmět: |
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| Zdroj: |
New Journal of Chemistry; 11/21/2023, Vol. 47 Issue 43, p19897-19905, 9p |
| Abstrakt: |
A benzothiazole-coupled NS4-macrocycle derivative L was synthesized via a three-step route for the detection of Hg2+. Chemosensor L, as a dual channel (UV-vis and fluorescence) receptor, undergoes a significant hypsochromic shift and fluorescence quenching in the presence of Hg(ClO4)2 in ethanol/DMSO (v/v, 9 : 1), showing remarkable selectivity towards Hg2+ over other metal ions both in single and competitive metal ion experiments. The observed chelation-enhanced quenching (CHEQ) effect seems to be attributed to the combination of the heavy atom effect and Hg2+⋯benzothiazole interaction. However, such Hg2+ sensing responses in both channels were not observed for non-perchlorate anions. To explain the anion-dependent Hg2+ sensing, systematic studies on the complexations of L with Hg(ClO4)2 and HgI2 were performed via UV-vis/fluorescence titrations, comparative NMR, and anion exchange. Taken together, the Hg2+ sensing critically depends on the Hg–Ntert bonding which triggers the hypsochromic shift or the CHEQ effect. A weaker coordinating ClO4− allows an endocyclic complex to form with the Hg–Ntert bond being responsive, while a stronger coordinating I− leads to exocyclic complexation without the Hg–Ntert bond being non-responsive. The crystal structure of the mercury(II) iodide complex [Hg2(L)I4] featuring an exocyclic dinuclear form also supports this explanation. This result could present a new perspective on the design of macrocycle-based chemosensors. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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