pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes

Copper ions in the active sites of several proteins/enzymes interact with phenols and quinones, and this interaction is associated to the reactivity of the enzymes. In this study the speciation of the Cu2+ with iminodiacetic phenolate/hydroquinonate ligands has been examined by pH-potentiometry. The...

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Main Authors: Marios Stylianou, Anastasios D. Keramidas, Chryssoula Drouza
Format: Article
Language:English
Published: Wiley 2010-01-01
Series:Bioinorganic Chemistry and Applications
Online Access:http://dx.doi.org/10.1155/2010/125717
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author Marios Stylianou
Anastasios D. Keramidas
Chryssoula Drouza
author_facet Marios Stylianou
Anastasios D. Keramidas
Chryssoula Drouza
author_sort Marios Stylianou
collection DOAJ
description Copper ions in the active sites of several proteins/enzymes interact with phenols and quinones, and this interaction is associated to the reactivity of the enzymes. In this study the speciation of the Cu2+ with iminodiacetic phenolate/hydroquinonate ligands has been examined by pH-potentiometry. The results reveal that the iminodiacetic phenol ligand forms mononuclear complexes with Cu2+ at acidic and alkaline pHs, and a binuclear Ophenolate-bridged complex at pH range from 7 to 8.5. The binucleating hydroquinone ligand forms only 2 : 1 metal to ligand complexes in solution. The pK values of the protonation of the phenolate oxygen of the two ligands are reduced about 2 units after complexation with the metal ion and are close to the pK values for the copper-interacting tyrosine phenol oxygen in copper enzymes.
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spelling doaj-art-e8d8464bc15b49d18a6226169d31c1542025-08-20T02:21:57ZengWileyBioinorganic Chemistry and Applications1565-36331687-479X2010-01-01201010.1155/2010/125717125717pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) ComplexesMarios Stylianou0Anastasios D. Keramidas1Chryssoula Drouza2Department of Chemistry, University of Cyprus, 1678 Nicosia, CyprusDepartment of Chemistry, University of Cyprus, 1678 Nicosia, CyprusAgricultural Production and Biotechnology and Food Science, Cyprus University of Technology, P. O. Box 50329, 3603 Lemesos, CyprusCopper ions in the active sites of several proteins/enzymes interact with phenols and quinones, and this interaction is associated to the reactivity of the enzymes. In this study the speciation of the Cu2+ with iminodiacetic phenolate/hydroquinonate ligands has been examined by pH-potentiometry. The results reveal that the iminodiacetic phenol ligand forms mononuclear complexes with Cu2+ at acidic and alkaline pHs, and a binuclear Ophenolate-bridged complex at pH range from 7 to 8.5. The binucleating hydroquinone ligand forms only 2 : 1 metal to ligand complexes in solution. The pK values of the protonation of the phenolate oxygen of the two ligands are reduced about 2 units after complexation with the metal ion and are close to the pK values for the copper-interacting tyrosine phenol oxygen in copper enzymes.http://dx.doi.org/10.1155/2010/125717
spellingShingle Marios Stylianou
Anastasios D. Keramidas
Chryssoula Drouza
pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
Bioinorganic Chemistry and Applications
title pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
title_full pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
title_fullStr pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
title_full_unstemmed pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
title_short pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
title_sort ph potentiometric investigation towards chelating tendencies of p hydroquinone and phenol iminodiacetate copper ii complexes
url http://dx.doi.org/10.1155/2010/125717
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