Anion Binding‐Induced White Light Emission using a Water‐Tolerant Fluorescent Molecular Tweezer |
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| Authors: | Rajesh Kumar Dr. Aasheesh Srivastava |
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| Affiliation: | Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, India |
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| Abstract: | A novel fluorescent molecular tweezer (FMT), built on the pyridine‐2,6‐bis‐carboxamide framework, has been developed that, in presence of a red emitter, gives rise to white light emission in response to the addition of H2PO4? anions. The FMT incorporates two pyrene moieties as fluorescent reporter units and a strategically placed amine residue that imparts pH sensitivity to the fluorescence and offers additional electrostatic/hydrogen‐bonding interactions to the anions. As a result, this FMT selectively binds monoanionic tetrahedral oxyanions such as H2PO4? and HSO4? that contain hydrogen bond donors and acceptors, and can sense their presence in aqueous acetonitrile through changes in fluorescence. Anion binding results in excimer formation by the pyrenes and a bluish‐green emission from the FMT. Both amide and amine residues of the FMT interact with these anions. The binding stoichiometry with H2PO4? and HSO4? was found to be 1:1 and affinity of the FMT for these anions is of the order of 104 m ?1. The limit of detection for H2PO4? was found to be 13 nm . Addition of a perylene monoimide‐based red emitter gives rise to panchromatic emission perceived as white light. |
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| Keywords: | anion sensing electron transfer excimer formation fluorescence self-assembly |
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