Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/44196
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Type: Journal article
Title: UV-Vis and fluorimetric Al³⁺, Zn²⁺, Cd²⁺ and Pb²⁺ complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone
Other Titles: UV-Vis and fluorimetric Al(3+), Zn(2+), Cd(2+) and Pb(2+) complexation studies of two 3-hydroxyflavones and a 3-hydroxythioflavone
Author: Valente, J.
Buntine, M.
Lincoln, S.
Ward, A.
Citation: Inorganica Chimica Acta, 2007; 360(10):3380-3386
Publisher: Elsevier Science SA
Issue Date: 2007
ISSN: 0020-1693
1873-3255
Statement of
Responsibility: 
John V. Valente, Mark A. Buntine, Stephen F.Lincoln and A. David Ward
Abstract: The complexation of Al³⁺, Zn²⁺, Cd²⁺ and Pb²⁺ by the 3-hydroxyflavones: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-one (H1) and 3-hydroxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one (H2), and by the 3-methoxythioflavone: 3-hydroxy-2-(2-methoxyphenyl)- 4H-1-benzopyran-4-thione (H3) have been studied spectrophotometrically and fluorimetrically to determine the corresponding complexation constants, Ksp and Kfl, in 5:95 water:ethanol (v/v) solution for which [HClO4] was either 10⁻² or 10⁻⁵ mol dm⁻³ and I = 0.10 mol dm⁻³ (NaClO₄) at 298.2 K. Complexation occurs dominantly through the deprotonated ligand for [Al(1)]²⁺ and [Al(2)]²⁺ for which logKsp = 4.51 and 4.73, respectively, in 10⁻² mol dm⁻³ HClO₄ and 4.21 and 4.61 in 10⁻⁵ mol dm⁻³ HClO₄. For Pb²⁺ complexation by H1, H2 and H3 is characterized by logKsp = 2.20, 2.57 and 3.22, respectively, in 10⁻² mol dm⁻³ HClO₄ and 4.70, 5.38 and 5.74 in 10⁻⁵ mol dm⁻³ HClO₄. Equilibrium mixtures of [Pb(H1)]²⁺ and [Pb1]⁺, [Pb(H2)]²⁺ and [Pb2]⁺, and [Pb(H3)]²⁺ and [Pb3]⁺ appear to be formed. Complexation of Zn²⁺ and Cd²⁺ by all three ligands was only detected in 10⁻⁵ mol dm⁻³ HClO₄. For Zn²⁺ complexation by H1, H2 and H3 logKsp = 3.22, 3.74 and 4.46 and for Cd²⁺ the corresponding values are 2.39, 2.40 and 3.72 for Cd²⁺. Only [Al1] ²⁺ and [Al2] ²⁺ show significant fluorescence and are characterized by logKfl = 6.30 and 7.49 in 10⁻² mol dm⁻³ HClO₄.
Keywords: 3-Hydroxyflavones; 3-Hydroxythioflavones; Metal complexes; Stability constants; Fluorescence
Description: Copyright © 2007 Published by Elsevier B.V.
RMID: 0020071235
DOI: 10.1016/j.ica.2007.04.011
Description (link): http://www.elsevier.com/wps/find/journaldescription.cws_home/504086/description#description
Appears in Collections:Chemistry publications
Environment Institute publications

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