Complex Formation between Iron(III) and Tartaric and Citric Acids in a Wide pH Range 1 to 13 as Studied by Magnetic Susceptibility Measurements

Yokoi, Hiroshi; Mitani, Tsuyoshi; Mori, Yasuyoshi; Kawata, Satoshi

doi:10.1246/cl.1994.281

Cited by 22 publications

(22 citation statements)

References 12 publications

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“…These results are in agreement with those reported in the literature at almost the same pH. [37] The shortest FeϪO bond is 1.942 Å for the FeϪO (alkoxide) bond. The other distances are 1.995 Å for the FeϪO (central carboxylate) bond and 2.055 Å for the FeϪO (terminal carboxylate) bonds.…”

Section: Zero-field Splitting Parameters and Structures Of Compounds supporting

confidence: 93%

High‐Field EPR Study of Frozen Aqueous Solutions of Iron(III) Citrate Complexes

et al. 2005

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Keywords: High-field EPR spectroscopy / Iron / Coordination chemistry / Citrate ligand / Tripodal ligand / Spin crossover High-field electron paramagnetic resonance spectra have been measured for frozen aqueous solutions of Fe III citrate at acidic and neutral pH values. At high fields (up to 12 T) and high frequencies (95, 190 and 285 GHz), fine-structure peaks due to resonance between Kramers doublets (±1/2, ±3/2, ±5/ 2) of an S = 5/2 species can be observed when the experiments are performed at high temperatures. A full-matrix diagonalisation approach has been used to derive the spinHamiltonian parameters for the S = 5/2 spin state. In acidic media (pH = 2), the spacing of the fine structure reveals that the value of the axial zero-field splitting (ZFS) parameter D is −0.12 cm −1 without rhombicity. A small but significant g anisotropy can be observed which depends slightly on the frequency and the temperature (g x = 2.014, g y = 2.014 and

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Section: Zero-field Splitting Parameters and Structures Of Compounds supporting

confidence: 93%

High‐Field EPR Study of Frozen Aqueous Solutions of Iron(III) Citrate Complexes

et al. 2005

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“…Fe(II) forms a monomeric complex but Fe(III) binds much more strongly, forming dimeric and trimeric complexes in the pH range of wine (Timberlake 1964, Yokoi et al 1994). In the presence of just three equivalents of tartaric acid, the reduction potential of the couple is reduced to ~350 mV at pH 3.6 (Green and Parkins 1961).…”

Section: Redox Systems In Winementioning

confidence: 99%

Review of Oxidative Processes in Wine and Value of Reduction Potentials in Enology

Danilewicz¹

2011

Am. J. Enol. Vitic.

103

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“…Two studies performed in aqueous solutions at up to pH 4 have yielded conflicting results! [9,10] The monoferric dicitrate [Fe(H x cit) 2 ] (5À2x)À species has been claimed to be recognized by the E. coli transport system, and indeed seems to be the only complex of established biological relevance. [11] The [Fe(cit) 2 ] 5À species has been structurally characterized (crystallized from solution at pH 8) by Matzapetakis et al [12] The "recognition" of the mononuclear dicitrate species may be questioned in the light of recent papers describing the crystallographic structure of FecA, the outer membrane receptor of the citrate system of E. coli, which binds a dinuclear ferric dicitrate.…”

Section: Introductionmentioning

confidence: 99%

“…According to this scheme, the variation of k 2 obs with [L] can be described by the rate law given in Equation (10).…”

mentioning

confidence: 99%

New Trends in the Chemistry of Iron(III) Citrate Complexes: Correlations between X‐ray Structures and Solution Species Probed by Electrospray Mass Spectrometry and Kinetics of Iron Uptake from Citrate by Iron Chelators

Gautier‐Luneau

Merle

Phanon

et al. 2005

Chemistry A European J

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Despite the crucial role of "iron(III) citrate systems" in the iron metabolism of living organisms (bacteria as well as plants or mammals), the coordination chemistry of ferric citrate remains poorly defined. Variations in the experimental conditions used for the preparation of so-called ferric citrates (iron salt, Fe:cit molar ratio, base, pH, temperature, solvent) lead to several different species, which are in equilibrium in solution. To date, six different anionic complexes have been structurally characterized in the solid state, by ourselves or others. In the work described herein, we have established the experimental conditions leading to each of them. Five were obtained from aqueous solution. With the exception of a nonanuclear species (of which fragments have been detected), all were identified in aqueous solution on the basis of electrospray ionization mass spectrometry. In addition, the spectra revealed a new trinuclear species, which could not be crystallized. Kinetic studies of iron uptake from citrate species by iron chelators confirmed the results indicated by the ESI-MS studies. These studies also allowed the relative molar fraction of mononuclear versus polynuclear complexes to be determined, which depends on the Fe:cit molar ratio.

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Complex Formation between Iron(III) and Tartaric and Citric Acids in a Wide pH Range 1 to 13 as Studied by Magnetic Susceptibility Measurements

Cited by 22 publications

References 12 publications

High‐Field EPR Study of Frozen Aqueous Solutions of Iron(III) Citrate Complexes

High‐Field EPR Study of Frozen Aqueous Solutions of Iron(III) Citrate Complexes

Review of Oxidative Processes in Wine and Value of Reduction Potentials in Enology

New Trends in the Chemistry of Iron(III) Citrate Complexes: Correlations between X‐ray Structures and Solution Species Probed by Electrospray Mass Spectrometry and Kinetics of Iron Uptake from Citrate by Iron Chelators

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