Harsha KG, Ananda Rao B, Baggi TR, Prabhakar S, Jayathirtha Rao V. Thiophene-phenylquinazoline probe for selective ratiometric fluorescence and visual detection of Fe(iii) and turn-off fluorescence for I
- and its applications.
Photochem Photobiol Sci 2020;
19:1707-1716. [PMID:
33216103 DOI:
10.1039/d0pp00193g]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A 2,5-bis(4-phenylquinazolin-2-yl)thiophene (BQT) probe is designed, synthesized and explored for selective ratiometric fluorescence and visual detection of Fe3+ and as a turn-off fluorescence probe for I- anion. BQT is colorless and has blue emission in CH3CN solution. BQT selectively complexes with Fe3+, turns its solution from colorless to greenish yellow and enables the ratiometric sensing of Fe3+ with limit of detection (LOD) and limit of quantitation (LOQ) of 2 × 10-8 M and 6.1 × 10-8 M, respectively. Binding constant of BQT with Fe3+ is found to be 4.1 × 10-4 M-1. BQT is also able to sense I- anion present in aqueous solution by selectively turning colorless to yellow and fluorescence quenching with a LOD of 1.7 × 10-7 M and LOQ of 5.2 × 10-7 M. BQT sensing ability is not influenced by the presence of other metal ions and anions in the vicinity. The BQT-Fe3+ complex is thoroughly characterized using MALDI-TOF, NMR and Job's plot. A reversibility experiment with EDTA suggests BQT is a reversible fluorescent chemosensor for Fe3+ ions. The spectroscopic data of BQT and its complexes are employed to construct a field test kit for qualitative analysis and INHIBIT logic gate.
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