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EDTA Complex (edta + complex)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Complexes of Yb3+ with EDTA and CDTA , Molecular and Electronic Structure

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2008
Janicki
Abstract Two Yb3+ compounds, [C(NH2)3]2[Yb(EDTA)(H2O)2]ClO4·6H2O and [C(NH2)3][Yb(CDTA)(H2O)2]·4H2O, where EDTA is the ethylenediaminetetraacetate anion and CDTA is the trans -1,2-diaminecyclohexane- N,N,N,,N, -tetraacetate anion, were obtained and their crystal structures and spectroscopic properties were determined. In both compounds, the coordination geometries of the eight-coordinate Yb3+ ion are very similar. In each case, the inner sphere of the metal ion consists of four carboxyl oxygen atoms, two nitrogen atoms and two water molecules. The complexes were characterized by UV/Vis/NIR absorption at different temperatures and IR spectroscopy. The spectroscopic results revealed high sensitivity of the electronic 4f13 configuration upon minor changes in the coordination geometry around the Yb3+ ion. These data also demonstrate that species present in solutions of Yb3+,EDTA are similar to those found in the crystal, whereas in solutions of Yb3+,CDTA an equilibrium between at least two different forms exists. For the Yb3+,EDTA complex in solution and in the crystalline state, a charge-transfer transition was detected. Theoretical calculations revealed its complicated (Yb , ligand and ligand , Yb) character.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Mössbauer Investigation of Peroxo Species in the Iron(III),EDTA,H2O2 System

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2005
Virender K. Sharma
Abstract The reaction of a diiron(III),EDTA complex with H2O2 in alkaline medium is studied by Mössbauer spectroscopy in conjunction with the rapid-freeze/quench technique in order to identify possible intermediate species during the formation and decomposition of the purple (EDTA)FeIII(,2 -O2)3, complex ion. Starting from the six-coordinate [FeIIIEDTA], species at acidic pH, it is demonstrated that mononuclear complexes formed at a pH of about 1 are convert into the diiron(III),EDTA complex [(EDTA)FeIII -O-FeIII(EDTA)]4, upon raising the pH to around 10.4. H2O2 reacts with the diiron(III) complex to give peroxide/hydroperoxide related adducts. Initially, the reaction tears apart the dimers to form a peroxo adduct, namely the seven-coordinate mononuclear [(EDTA)FeIII(,2 -O2)]3,, which is stable only at very high pH. The decomposition of this peroxo adduct gives two new species, which are reported for the first time. The Mössbauer parameters of these species suggest a six-coordinate ,-peroxodiiron(III) complex [(EDTA)FeIII -(OO)-FeIII(EDTA)]4, and a seven-coordinate ,-hydroxo-,-peroxodiiron(III) complex [(EDTA)FeIII -(OO)(OH)-FeIII(EDTA)]5,. A badly resolved, extremely broad component is observed in the Mössbauer spectra during the conversion of the monomer to dimeric peroxo species, which may be attributed to the short-lived [(EDTA)FeIII -OO]3, or [(EDTA)FeIII -OOH]2, intermediate species. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

A heterogeneous kinetic model of the oxidative polymerization of 2,6-dimethylphenol with a copper-EDTA complex in water

AICHE JOURNAL, Issue 10 2009
Qun Liu
Abstract The heterogeneous oxidative polymerization kinetics of 2,6-dimethylphenol (DMP) catalyzed by a copper(II)-EDTA complex in water was studied. During the oxidative polymerization of DMP in water the oxygen uptake rate increases with an increase in DMP concentration and an increase in temperature. The Michaelis,Menten kinetic model as applied to the polymerization of DMP in organic solvents is not appropriate for the description of the full course of DMP polymerization in water. A new heterogeneous kinetic model is proposed to describe the catalyst deactivation during the oxidative polymerization as well as the difference in reactivity between the monomer, water-soluble oligomer and water-insoluble oligomer. The polymerization rate estimated by the new model is consistent with the measured data. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Recovering Ga(III) from coordination complexes using pyridine 2,6-dicarboxylic acid chelation ion chromatography

BIOMEDICAL CHROMATOGRAPHY, Issue 9 2010
K. Staff
Abstract Ion exchange chelation chromatography is an effective means to extract metals from coordination complexes and biological samples; however there is a lack of data to verify the nature of metal complexes that can be successfully analysed using such a procedure. The aim of this study was to assess the capability of pyridine 2,6-dicarboxylic acid (PDCA) to extract and quantify Ga(III) from a range of environments using standard liquid chromatography apparatus. The PDCA chelation method generated a single Ga(III) peak with a retention time of 2.55 ± 0.02 min, a precision of <2% and a limit of detection of 110 ,M. Ga(III) hydroxide complexes (highest stability constant 15.66) were used to successfully cross-validate the chelation method with inductively coupled plasma mass spectrometry. The PDCA assay extracted 96.9 ± 1.2% of the spiked Ga(III) from porcine mucus and 100.7 ± 2.7% from a citrate complex (stability constant 10.02), but only ca 50% from an EDTA complex (stability constant 22.01). These data suggest that PDCA chelation can be considered a suitable alternative to inductively coupled plasma mass spectrometry for Ga(III) quantification from all but the most strongly bound coordinated complexes i.e. a stability constant of <15. Copyright © 2010 John Wiley & Sons, Ltd. [source]