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Anion Binding‐Induced White Light Emission using a Water‐Tolerant Fluorescent Molecular Tweezer
Author(s) -
Kumar Rajesh,
Srivastava Aasheesh
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201504269
Subject(s) - chemistry , fluorescence , photochemistry , pyrene , perylene , hydrogen bond , amide , amine gas treating , aqueous solution , excimer , acetonitrile , pyridine , ether , molecule , organic chemistry , physics , quantum mechanics
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 H 2 PO 4 − 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 H 2 PO 4 − and HSO 4 − 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 H 2 PO 4 − and HSO 4 − was found to be 1:1 and affinity of the FMT for these anions is of the order of 10 4 m −1 . The limit of detection for H 2 PO 4 − was found to be 13 n m . Addition of a perylene monoimide‐based red emitter gives rise to panchromatic emission perceived as white light.