Kadarkaraisamy Mariappan, Madhubabu Alaparthi, C. Richards
Feb 1, 2019
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Journal
Polyhedron
Abstract
Abstract Oxidation of sulfur in 1,8-oxybis(ethyleneethoxyethylenethio)anthracene-9,10-dione (1) using 30% hydrogen peroxide or sodium perborate yielded 1,8-oxybis(ethyleneethoxyethylenesulfoxide)anthracene-9,10-dione (2) and 1,8-oxybis(ethyleneethoxyethylenesulfone)anthracene-9,10-dione (3) respectively. Both sulfoxides (2) and sulfones (3) were characterized thoroughly by NMR and single-crystal X-ray crystallography. Compound 2 produced an intense green emission upon association with Ca(II) in acetonitrile. Selectivity for Ca(II) is distinctly improved as compared to the parent (1) as well as the oxygen analogue of 1 (1,8-oxybis(ethyleneethoxyethyleneoxy)anthracene-9,10-dione). UV–Visible & emission titrations and Job’s plot studies reveal that compound 2 formed 2:1 complexes with Ca(II) and Pb(II) in acetonitrile solution, which was confirmed by single-crystal X-ray diffraction. Ca(II) and Pb(II) are complexed within the macrocycle through the anthraquinone carbonyl oxygen, two ether oxygens and two oxygens of the sulfoxide. Reversibility between compound 2 and its Ca(II) complex is studied using UV–Vis and emission experiments mixing with EDTA. Unlike compound 2, compound 3 is non-emissive with metal ions. X-ray studies of Pb(II) complex of 3 revealed that a unique mixed complex (2:1 and 1:1 ratios) formed within the unit cell.