A highly selective pyridoxal-based chemosensor for the detection of Zn() and application in live-cell imaging; X-ray crystallography of pyridoxal-TRIS Schiff-base Zn() and Cu() complexes
In a simple, one-step reaction, we have synthesized a pyridoxal-based chemosensor by reacting tris(hydroxymethyl)aminomethane (TRIS) together with pyridoxal hydrochloride to yield a Schiff-base ligand that is highly selective for the detection of Zn( ii ) ion. Both the ligand and the Zn( ii ) comple...
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Published in | RSC advances Vol. 11; no. 54; pp. 34181 - 34192 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Royal Society of Chemistry
21.10.2021
The Royal Society of Chemistry |
Subjects | |
Online Access | Get full text |
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Summary: | In a simple, one-step reaction, we have synthesized a pyridoxal-based chemosensor by reacting tris(hydroxymethyl)aminomethane (TRIS) together with pyridoxal hydrochloride to yield a Schiff-base ligand that is highly selective for the detection of Zn(
ii
) ion. Both the ligand and the Zn(
ii
) complex have been characterized by
1
H &
13
C NMR, ESI-MS, CHN analyses, and X-ray crystallography. The optical properties of the synthesized ligand were investigated in an aqueous buffer solution and found to be highly selective and sensitive toward Zn(
ii
) ion through a fluorescence turn-on response. The competition studies reveal the response for zinc ion is unaffected by all alkali and alkaline earth metals; and suppressed by Cu(
ii
) ion. The ligand itself shows a weak fluorescence intensity (quantum yield,
Φ
= 0.04), and the addition of zinc ion enhanced the fluorescence intensity 12-fold (quantum yield,
Φ
= 0.48). The detection limit for zinc ion was 2.77 × 10
−8
M, which is significantly lower than the WHO's guideline (76.5 μM). Addition of EDTA to a solution containing the ligand-Zn(
ii
) complex quenched the fluorescence, indicating the reversibility of Zn(
ii
) binding. Stoichiometric studies indicated the formation of a 2 : 1 L
2
Zn complex with a binding constant of 1.2 × 10
9
M
−2
(±25%). The crystal structure of the zinc complex shows the same hydrated L
2
Zn complex, with Zn(
ii
) ion binding with an octahedral coordination geometry. We also synthesized the copper(
ii
) complex of the ligand, and the crystal structure showed the formation of a 1 : 1 adduct, revealing 1-dimensional polymeric networks with octahedral coordinated Cu(
ii
). The ligand was employed as a sensor to detect zinc ion in HEK293 cell lines derived from human embryonic kidney cells grown in tissue culture which showed strong luminescence in the presence of Zn(
ii
). We believe that the outstanding turn-on response, sensitivity, selectivity, lower detection limit, and reversibility toward zinc ion will find further application in chemical and biological science.
The synthesis, characterization, X-ray crystallography, and live-cell imaging of pyridoxal-TRIS Schiff-base ligand which is selective as a luminescence sensor to detect Zn(
ii
) ion, and the corresponding Zn(
ii
) and Cu(
ii
) complexes are described. |
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Bibliography: | 2095325 13 [1]Cu 2ClO 10.1039/d1ra05763d 2095332 Electronic supplementary information (ESI) available ( ) 2095330 C NMR, COSY NMR O 1 For ESI and crystallographic data in CIF or other electronic format see DOI − 2 5H Zn 4 and C-DEPT135 NMR, IR and ESI-MS spectrum of ligand, EDTA reversibility plot, pH effect plot, detection limit plot, UV-Vis and emission plot on addition of anions, ESI-MS of metal complex, quantum yield and detection limit calculation. CCDC 2+ H NMR ] ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2046-2069 2046-2069 |
DOI: | 10.1039/d1ra05763d |