A Chemodosimetric Approach for Fluorimetric Detection of Hg2+ Ions by Trinuclear Zn(II)/Cd(II) Schiff Base Complex: First Case of Intermediate Trapping in a Chemodosimetric Approach
Autor: | Debasis Das, Abani Sarkar, Tonmoy Chakraborty, Debabrata Samanta, Suvendu Maity, Aratrika Chakraborty, Suranjana Purkait |
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Rok vydání: | 2020 |
Předmět: |
Schiff base
010405 organic chemistry Ligand chemistry.chemical_element Zinc 010402 general chemistry 01 natural sciences Fluorescence Fluorescence spectroscopy 0104 chemical sciences Inorganic Chemistry Crystallography chemistry.chemical_compound chemistry Density functional theory Physical and Theoretical Chemistry Absorption (chemistry) Spectroscopy |
Zdroj: | Inorganic Chemistry. 59:9014-9028 |
ISSN: | 1520-510X 0020-1669 |
Popis: | The present work discloses the application of two fluorescent zinc and cadmium complexes (1 and 2) for sensing of Hg(II) ions through a chemodosimetric approach. The ligand under consideration in this work is a N2O donor Schiff base ligand (E)-4-bromo-2-(((2-morpholinoethyl)imino)methyl)phenol (HL), which has been harnessed to generate complexes [Zn3L2(OAc)4] (1) and [Cd3L2(OAc)4] (2). X-ray single crystal diffraction studies unveil the trinuclear skeleton of complexes 1 and 2. Both complexes have been found to be highly fluorescent in nature. However, the quantum efficiency of Zn(II) complex (1) dominates over the Cd(II) analogue (2). The absorption and emission spectroscopic properties of the complexes have been investigated by density functional theory. Complexes 1 and 2 can detect Hg2+ ions selectively by fluorescence quenching, and it is noteworthy to mention that the mechanism of sensing is unique as well as interesting. In the presence of Hg2+ ions, complexes 1 and 2 are transformed to mononuclear mercuric intermediate complex (3) and finally to a trinuclear mercuric complex (4) by hydrolysis. We have successfully trapped the intermediate complex 3, and we characterized it with the aid of X-ray crystallography. Transformation of complexes 1 and 2 to intermediate complex 3 and finally to 4 has been established by UV-vis spectroscopy, fluorescence spectroscopy, ESI-MS spectroscopy, 1H NMR spectroscopy, and X-ray crystallography. The spontaneity of the above conversion is well supported by thermodynamic aspects as reflected from density functional theoretical calculations. |
Databáze: | OpenAIRE |
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