Premium
Aminoquinoline‐Salicylaldimine Dyads as Highly Selective Turn‐On Fluorescent Sensors for Zinc (II) Ions
Author(s) -
Vongnam Kunnigar,
Aree Thammarat,
Sukwattanasinitt Mongkol,
Rashatasakhon Paitoon
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201800155
Subject(s) - deprotonation , fluorescence , chemistry , titration , naked eye , detection limit , chelation , zinc , quinoline , stoichiometry , aqueous solution , turn (biochemistry) , photochemistry , inorganic chemistry , ion , organic chemistry , chromatography , biochemistry , physics , quantum mechanics
Four new derivatives of 8‐aminoquinolines are successfully synthesized by extension of the π ‐conjugated system on the quinoline ring and incorporation of either the salicylaldimine or its reduced amino form. These compounds show selective fluorescence enhancement by Zn 2+ ion, attributing to the chelation‐enhanced fluorescence (CHEF) effects, in which the deprotonation of the amido –NH and phenolic ‐OH causes the internal charge transfer (ICT) process. The fluorescent signals of these compounds are shifted from the range of 391–562 nm to 535–590 nm upon addition of Zn 2+ . The sensing mechanism is investigated by 1 H NMR titration, mass spectrometry, and single crystal X‐ray diffraction analysis which suggests a 1:1 binding stoichiometry between the sensor and Zn 2+ . The detection limits of 0.024 to 0.431 μM and the association constants ranging between 7.0 × 10 3 and 1.2 × 10 4 M −1 can be estimated for these four sensors. One of these compounds is fabricated on wax‐patterned filter paper and used as a probe for Zn 2+ in aqueous solution with a naked‐eye detection limit at 10 μM.