Oxidized Derivatives of Octopus vulgaris and Carcinus aestuarii Hemocyanins at pH 7.5 and Related Models by X-ray Absorption Spectroscopy

Borghi, E.; Solari, Pier Lorenzo; Beltramini, Mariano; Bubacco, Luigi; Muro, Paolo Di; Salvato, Benedetto

doi:10.1016/s0006-3495(02)75667-1

Cited by 16 publications

(15 citation statements)

References 46 publications

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“…It has already been mentioned that in case of binuclear complexes, the metal–metal contribution in the spectra is superposed to the sample signals . Hence, in case of complexes 2 and 4 , firstly, the theoretical model generated for (Cu1) center using the available crystal structure of 1 has been fitted to the experimental data to determine the geometry about (Cu1) center in these complexes.…”

Section: Discussionmentioning

confidence: 99%

“…Synchrotron X‐ray absorption fine structure spectroscopy (XAFS) is an effective technique for selectively investigating the local coordination environment of metal ions . The analysis of the oscillations that occur at ~ 50 eV above the threshold of the X‐ray absorption spectrum, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…+1 and +2 oxidation states of the metal. Earlier workers have pointed out that the analysis of EXAFS spectra of binuclear metal complexes pose some problems because of the presence of two absorbing atoms, even when the absorbing atoms may be of the same element, and from the fact that the metal–metal contribution in the spectra is superposed to the sample signals. In the present work, we have attempted to investigate the geometry about (Cu1) center in all of these complexes and about the (Cu2) center in complexes 2 and 4 .…”

Section: Introductionmentioning

confidence: 99%

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XAFS investigations of copper(II) complexes with tetradentate Schiff base ligands

et al. 2012

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X‐ray absorption fine structure spectra have been investigated at the K‐edge of copper in copper(II) salen/salophen complexes: [Cu(salen)] (1), [Cu(salen)CuCl2].H2O (2), [Cu(salophen)] (3) and [Cu(salophen) CuCl2].H2O (4), where salen2− = N,N′‐ethylenebis (salicylidenaminato); salophen2− = o‐phenylenediaminebis(salicylidenaminato). Complexes 1 and 3 are supposed to have one type of copper centers (called (Cu1)) and complexes 2 and 4 two types of copper centers (called (Cu1) and (Cu2)) having different coordination environments and geometries. A theoretical model has been generated using the available crystallographic data of complex 1 and it has been used for analysis of the extended X‐ray absorption fine structure (EXAFS) data of the four complexes to obtain the structural parameters for (Cu1) center. For this center, the obtained Cu–Cu distance (3.2 Å) verifies the binuclear nature of all the complexes. For determining the coordination geometry around (Cu2) center in 2 and 4, a theoretical model has been generated using the crystal structure of a Cu(II) complex, [Cu(C16H12N2O2Cl2)]. This theoretical model has been fitted to the EXAFS data of 2 and 4 to obtain the structural parameters for (Cu2) center. The present analysis shows that (Cu1) center has square pyramidal geometry involving 2N and 3O donor atoms, whereas (Cu2) center has distorted tetrahedral geometry with 2O and 2Cl donor atoms. The values of the chemical shifts and presence of typical Cu(II) X‐ray absorption near‐edge spectroscopy features suggest that copper is in the +2 oxidation state in all these complexes. The intensity of ls → 3d pre‐edge feature has been used to investigate the geometry and binuclear nature of the complexes. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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XAFS investigations of copper(II) complexes with tetradentate Schiff base ligands

et al. 2012

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“…Conclusively, clear evidence was obtained on adsorption of Cu ions onto IRP samples which attribute to detection of CuO that allowed carbonyl groups from GMA to bond with. The local coordination environment of metal ions can be selectively investigated with XAFS spectroscopy [42]. XAFS is also capable of determining distances, the coordination number, and the types of atoms surrounding the metal centers [43].…”

Section: Adsorption Mechanismmentioning

confidence: 99%

Selectivity of Copper by Amine-Based Ion Recognition Polymer Adsorbent with Different Aliphatic Amines

et al. 2019

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This paper investigates the selectivity of GMA-based-non-woven fabrics adsorbent towards copper ion (Cu) functionalized with several aliphatic amines. The aliphatic amines used in this study were ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). The non-woven polyethylene/polypropylene fabrics (NWF) were grafted with glycidyl methacrylate (GMA) via pre-radiation grafting technique, followed by chemical functionalization with the aliphatic amine. To prepare the ion recognition polymer (IRP), the functionalized amine GMA-grafted-NWF sample was subjected to radiation crosslinking process along with the crosslinking agent, divinylbenzene (DVB), in the presence of Cu ion as a template in the matrix of the adsorbent. Functionalization with different aliphatic amine was carried out at different amine concentrations, grafting yield, reaction temperature, and reaction time to study the effect of different aliphatic amine onto amine density yield. At a concentration of 50% of amine and 50% of isopropanol, EDA, DETA, TETA, and TEPA had attained amine density around 5.12, 4.06, 3.04, and 2.56 mmol/g-ad, respectively. The amine density yield decreases further as the aliphatic amine chain grows longer. The experimental condition for amine functionalization process was fixed at 70% amine, 30% isopropanol, 60 °C for grafting temperature, and 2 h of grafting time for attaining 100% of grafting yield (Dg). The prepared adsorbents were characterized comprehensively in terms of structural and morphology with multiple analytical tools. An adsorptive removal and selectivity of Cu ion by the prepared adsorbent was investigated in a binary metal ion system. The IRP samples with a functional precursor of EDA, the smallest aliphatic amine had given the higher adsorption capacity and selectivity towards Cu ion. The selectivity of IRP samples reduces as the aliphatic amine chain grows longer, EDA to TEPA. However, IRP samples still exhibited remarkably higher selectivity in comparison to the amine immobilized GMA-g-NWF at similar adsorption experimental conditions. This observation indicates that IRP samples possess higher selectivity after incorporation of the ion recognition imprint technique via the radiation crosslinking process.

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“…Recently, we have reconsidered and resolved some fundamental aspects of the binuclear copper site for met-and metazido derivatives of Octopus vulgaris (mollusc) and Carcinus aestuarii (arthropod) Hcs at pH 7.5 (Borghi et al, 2002). The study described therein is part of a larger project in collaboration with B. Salvato's group in Padova and L. Casella's group in Pavia, carried out at the ESRF facility, which has also considered the XAS characterization of the hemocyanin derivatives from the same phyla at pH 5.5 and some related binuclear models without XRD.…”

Section: Introductionmentioning

confidence: 99%

Multiple-scattering XAS calculations for the characterization of the binuclear (type 3) copper sites of hemocyanins and related model compounds

Borghi

Solari

2004

J Synchrotron Radiat

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Our previous studies on the met- and met-azido-Hc forms from Octopus vulgaris (mollusc) and Carcinus aestuarii (arthropod) at pH 7.5 and on some related binuclear models without X-ray diffraction have considered and resolved some fundamental aspects of their binuclear type-3 copper site (i.e. correct values of the Cu-Cu distances; apical distortion, when present, at the copper site; presence and type of bridging groups). In this contribution the multiple-scattering (MS) calculations performed in order to refine the EXAFS modulation of the absorption spectra are presented. It is only with a composite and advanced approach that some severe problems, mainly deriving from the presence of two absorbing atoms and from the fact that the metal-metal contribution in the absorption spectra overlaps with the Cu-His signals, have been overcome. Results are also presented which indicate the role of the MS calculations in the XANES edge region, and which show how it is possible to extract quantitative information from this zone of the spectrum in order to refine the structure of the site also in the case of a binuclear centre.

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Oxidized Derivatives of Octopus vulgaris and Carcinus aestuarii Hemocyanins at pH 7.5 and Related Models by X-ray Absorption Spectroscopy

Cited by 16 publications

References 46 publications

XAFS investigations of copper(II) complexes with tetradentate Schiff base ligands

XAFS investigations of copper(II) complexes with tetradentate Schiff base ligands

Selectivity of Copper by Amine-Based Ion Recognition Polymer Adsorbent with Different Aliphatic Amines

Multiple-scattering XAS calculations for the characterization of the binuclear (type 3) copper sites of hemocyanins and related model compounds

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