Structural determination of Cu and Fe–Citrate complexes: theoretical investigation and analysis by ESI-MS

Bertoli, Alexandre C.; Carvalho, Ruy Inácio Neiva de; Freitas, Matheus P.; Ramalho, Teodorico C.; Mancini, Daiana T.; Oliveira, M. Conceição; Varennes, Amarílis de; Dias, Ana

doi:10.1016/j.jinorgbio.2014.12.008

Cited by 21 publications

(10 citation statements)

References 36 publications

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“…Adduct formation in ESI was particularly pronounced for the metal-citrate solutions, where none of the metal-citrate species previously reported by others (Gautier-Luneau et al, 2005;Nischwitz and Michalke, 2009;Silva et al, 2009;Bertoli et al, 2015) could be found, although their pH and stoichiometry settings were in a comparable range to those in this study. These discrepancies can primarily be explained by a re-distribution of Na + , Cl − , and H + (which occurred in the aqueous phase as free ions according to the PHREEQC calculations) during ionization and gas phase transfer.…”

Section: Metal-ligand Speciation Patterns: Integrity and Reproducibilitysupporting

confidence: 62%

“…These discrepancies can primarily be explained by a re-distribution of Na + , Cl − , and H + (which occurred in the aqueous phase as free ions according to the PHREEQC calculations) during ionization and gas phase transfer. For example, a Fe(Cit) monomer (m/z = 279.9078) and two Cu(Cit) 2 dimers (m/z = 465.9427 and 487.9246) had also been described by Bertoli et al (2015), albeit without a Cl − adduct for the former and without Na + adducts for the latter. Nischwitz and Michalke (2009) also observed a Cu(Cit) 2 complex, but with a NH + 3 instead of Na + adduct.…”

Section: Metal-ligand Speciation Patterns: Integrity and Reproducibilitymentioning

confidence: 99%

“…The ESI-MS measurements of known metal-ligand mixtures can be compared with speciation data acquired from other methods such as computational speciation modeling, crystallography, or complex affinity titrations. For example, the complexing behavior of citrate, an important natural metal chelator which forms highly diverse species with iron under different pH and stoichiometry conditions, has been studied by ESI-MS in comparison with complementary techniques, such as spectrophotometric titrations and chemical modeling (Gautier-Luneau et al, 2005;Nischwitz and Michalke, 2009;Silva et al, 2009;Bertoli et al, 2015). In parallel to these studies on artificial metal-organic compounds under well-constrained conditions, ESI-MS has recently been applied to identify unknown metal-binding ligands isolated from natural waters, which ubiquitously occur as a component of natural dissolved organic matter (DOM), and which govern the mobility and availability of bioactive trace metals such as iron (Fe) and copper (Cu) (McCormack et al, 2003;Ross et al, 2003;Mawji et al, 2008Mawji et al, , 2011Stenson, 2009;Velasquez et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…The focus of our study lays on Fe -and Cu-complexes due to their bioactive nature and high affinity for organic ligands (Van den Berg, 1984;Rue and Bruland, 1995;Buck and Bruland, 2005;Buck et al, 2007). For the qualitative study, we chose a representative range of previously described ligands with different functional groups, binding stoichiometries, and binding strengths (Table 1): Citrate is a naturally occurring, physiologically important metal chelator which has been studied in-depth by ESI-MS and other speciation methods (GautierLuneau et al, 2005;Nischwitz and Michalke, 2009;Silva et al, 2009;Bertoli et al, 2015). Because it is a tricarboxylate chelator with an additional binding hydroxyl group, it could be seen as a representative of natural DOM which is largely composed of C x H y O z compounds and also contains a high density of carboxyl and hydroxyl functional groups as revealed by NMR analyses (Hertkorn et al, 2006;Repeta, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

2016

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In recent years, electrospray-ionization mass spectrometry (ESI-MS) has been increasingly used to complement the bulk determination of metal-ligand equilibria, for example via competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV). However, ESI-MS speciation analyses may be impacted by instrumental artifacts such as reduction reactions, fragmentation, and adduct formation at the ESI source, changes in the ionization efficiencies of the detected species in relation to sample matrix, and peak overlaps in response to increasing sample complexity. In our study, equilibria of the known artificial ligands citrate, ethylenediaminetetraacetic acid (EDTA), 1-nitroso-2-naphthol (NN), and salicylaldoxime (SA) with iron (Fe) and copper (Cu) were investigated by ultra-high resolution ESI-MS, Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), under a variety of sample matrix and ionization settings. The acquired mass spectra were compared with metal-ligand equilibrium data from the literature as well as an adapted speciation model. Overall, the mass spectra produced representative species mentioned in previous reports and predicted by the speciation calculations, such as Fe(Cit), Cu(Cit) 2 , Fe(EDTA), Cu(EDTA), Fe(NN) 3 , and Cu(SA) 2 . The analyses furthermore revealed new species which had been hypothesized but not measured directly using other methods, for example ternary complexes of citrate with Fe and Cu, Cu(SA) monomers, and the dimer Fe(SA) 2 . Finally, parallel measurements of a Cu+SA calibration series and a Cu+SA+EDTA competition series indicated that FT-ICR-MS can produce linear responses and low detection limits analogous to those of ACSV. We propose that ultra-high resolution FT-ICR-MS can be used as a representative tool to study interactions of trace metals with artificial as well as natural, unknown ligands at the molecular level.

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Section: Metal-ligand Speciation Patterns: Integrity and Reproducibilitysupporting

confidence: 62%

Section: Metal-ligand Speciation Patterns: Integrity and Reproducibilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

2016

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“…62 The ESI-MS method has been used in a wide variety of fields to study the formation, stoichiometry and speciation of metal complexes of organic ligands. [63][64][65] The ESI-MS spectra obtained for the Cu(II)-H1A/H12A, Cu(II)-H1A/H9A, and Cu(II)-H1A/H6A 1 : 1 metal-to-ligand molar ratio systems recorded in positive mode show dominant molecular ions: [CuL] 2+ (m/z, 597.7 Da). For the Cu(II)-H1A/H12A 1 : 1 metal-to-ligand system the [CuH −1 L] + molecular ion was also observed (m/z, 1195,5 Da, Fig.…”

Section: Dalton Transactions Papermentioning

confidence: 99%

Copper(ii) complexes of terminally free alloferon mutants containing two histidyl binding sites inside peptide chain structure and stability

2015

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Mononuclear and polynuclear copper(II) complexes of alloferon 1 with point mutations, H1A/H12A H2N-A(1)GVSGH(6)GQH(9)GVA(12)G-COOH, H1A/H9A H2N-A(1)GVSGH(6)GQA(9)GVH(12)G-COOH, and H1A/H6A H2N-A(1)GVSGA(6)GQH(9)GVH(12)G-COOH, have been studied by potentiometric, UV-visible, CD, and EPR spectroscopy, and mass spectrometry (MS) methods. Complete complex speciation at different metal-to-ligand molar ratios ranging from 1 : 1 to 3 : 1 was obtained. Over a wide 6-8 pH range, including physiological pH 7.4, and a 1 : 1 metal-to-ligand molar ratio, the peptides studied formed a CuH-1L complex with the 4N{NH2,N(-),2NIm} coordination mode. The presence of the 4N binding site for the CuH-1L complexes prevented the deprotonation and coordination of the second amide nitrogen atom to copper(II) ions (pK-1/-2 7.83-8.07) compared to that of pentaGly (6.81). The amine nitrogen donor and two imidazole nitrogen atoms (H(6)H(9), H(6)H(12) and H(9)H(12)) can be considered to be independent metal-binding sites in the species formed. As a consequence, di- and trinuclear complexes for the metal-to-ligand 2 : 1 and 3 : 1 molar ratios dominate in the solution, respectively. For the Cu(II)-H1A/H9A and Cu(II)-H1A/H12A systems, the Cu3H-9L complexes are likely formed by the coordination of amide nitrogen atoms towards C-termini with ring sizes (7,5,5).

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Overcoming the Inhibition Effects of Citrate: Precipitation of Ferromagnetic Magnetite Nanoparticles with Tunable Morphology, Magnetic Properties, and Surface Charge via Ferrous Citrate Oxidation

Granath

Mandel

Löbmann

2021

Part & Part Syst Charact

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This study demonstrates how the method of thermally assisted oxidative precipitation in water can be opened for—the so far neglected—metal organic iron(II) complexes (herein: citrate) in order to obtain, in one step, ferromagnetic magnetite nanoparticles, possessing essential ligand properties. Based on a dedicated analysis of the specific precursor in combination with the consideration of known properties of the ligand, it is possible to identify existing inhibition‐attributes of the iron organyl such that these can be overcome. Moreover, they can be exploited in a targeted manner; thus, simply by changing concentrations, a variety of magnetite nanoparticle morphologies with distinct properties can be obtained. In the case of the herein investigated ferrous citrate, three major inhibition effects are identified. While two of them efficiently prevent the formation of magnetite and need to be addressed to be overcome, the third can be exploited to selectively synthesize, for example, relatively stable carboxyl group‐bearing nuclei clusters, exhibiting the properties of magnetically responsive photonic crystals, or relatively large mesocrystals, whose intraparticular magnetic interactions are apparently disturbed.

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Structural determination of Cu and Fe–Citrate complexes: theoretical investigation and analysis by ESI-MS

Cited by 21 publications

References 36 publications

Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

Copper(ii) complexes of terminally free alloferon mutants containing two histidyl binding sites inside peptide chain structure and stability

Overcoming the Inhibition Effects of Citrate: Precipitation of Ferromagnetic Magnetite Nanoparticles with Tunable Morphology, Magnetic Properties, and Surface Charge via Ferrous Citrate Oxidation

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