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A Highly Sensitive and Selective Fluorescent Sensor for Zinc(II) Ions Based on a 1,2,3‐Triazolyl‐Functionalized 2,2’‐Dipicolylamine (DPA)
Author(s) -
Waheed Abdul,
Ahmad Tauqir,
Haroon Muhammad,
Ullah Nisar
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202000928
Subject(s) - bathochromic shift , moiety , chemistry , fluorescence , stoichiometry , zinc , selectivity , photochemistry , proton nmr , detection limit , inorganic chemistry , combinatorial chemistry , stereochemistry , organic chemistry , catalysis , physics , quantum mechanics , chromatography
The design and synthesis of a new triazolyl‐DPA ( TAZDPA ) based Zn 2+ fluorescent sensor is reported. The structural architect of TAZDPA contains 2,2’‐dipicolylamine (DPA) and 1,2,3‐triazolyl moiety as chelators, which synergistically coordinate with Zn 2+ , resulting in dramatic fluorescent emission enhancement and a notable bathochromic shift due to the inhibition of photoinduced electron transfer (PET) process. Solution state structural characterization and molecular modeling of TAZDPA suggest that N3 of 1,2,3‐triazolyl moiety and DPA coordinate with Zn 2+ to afford five‐membered coordination ring. The binding behavior and stoichiometry of the TAZDPA /Zn 2+ complex was studied by Job's plot, which suggested 1 : 1 stoichiometry. The nature of binding behavior of TAZDPA with Zn 2+ was validated by 1 H‐NMR that revealed a distinct downfield shift of DPA and triazolyl protons. Under physiological condition, TAZDPA displayed high selectivity for Zn 2+ over a wide range of competing common cations, exhibiting ultra‐sensitivity with a limit of detection (LOD) of 8.3×10 1 nM. This implies that TAZDPA can detect chronic Zn 2+ concentration for freshwater (>1.84 μM) denoted by the U.S. Environmental Protection Agency (EPA).