“…Moreover, the appearance of shoulder peak B at 8985 eV indicates that the configuration of copper extracts in organic phases is plane square because the electron of s-orbital can migrate to the z -direction of the p-orbital with an empty state (1s → 4p z ). Similar spectral signatures were also observed for copper complexes with the plane square configuration . From these symmetry indications, the structural sketch of copper extracts drawn in Figure may be supposed.…”
Section: Resultssupporting
confidence: 71%
“…Compared with the case of tetraamminecopper(II), the XANES feature of the extracted copper complexes in organic phases is evidently different because of the chelate effect and conjugation effect of β-diketone ligands. This phenomenon was also reported for the structure of other tetracoordinated copper species . For instance, Chaboy et al investigated the coordination structure of four nitrogen-containing ligands (ammonia, ethylenediamine, phthalocyanine, and glycine) with copper(II) by X-ray absorption spectroscopy.…”
Section: Resultssupporting
confidence: 54%
“…This phenomenon was also reported for the structure of other tetracoordinated copper species. 26 For instance, Chaboy et al investigated the coordination structure of four nitrogen-containing ligands (ammonia, ethylenediamine, phthalocyanine, and glycine) with copper(II) by X-ray absorption spectroscopy. They found that although four copper species are tetracoordinated structure, their XANES features are evidently different, indicating the structure and property of ligands have pronounced effect on the geometry of coordinated ions.…”
Section: Resultsmentioning
confidence: 99%
“…Similar spectral signatures were also observed for copper complexes with the plane square configuration. 26 From these symmetry indications, the structural sketch of copper extracts drawn in Figure 2 1. There is no distinct difference on the parameters for inner-sphere coordination of copper extracts.…”
A microscopic investigation on the extraction process of copper(II) in ammoniacal solutions has been performed by X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculation. The structural change of copper(II) species in ammoniacal solution has been derived from X-ray absorption near-edge spectroscopy (XANES) by principal component analysis and linear combination fitting. It was found that the coordination structure of the extracted copper complex in the organic phases is planar square and independent of the aqueous pH, whereas the geometries of copper(II) species in ammoniacal solutions changed from axially elongated octahedron to distorted planar square with increase of pH. The coordination geometry and structural parameters of copper(II) species were further obtained by extended X-ray absorption fine structure (EXAFS) fitting and DFT calculation with the B3LYP functional. These results reveal that the formation of tetracoordinated copper(II) ammine species can evidently inhibit the copper extraction reaction. Thus, the extraction mechanism of copper(II) in ammoniacal solutions has been elucidated in view of the microscopic structural aspects of copper species in both organic phase and ammoniacal solutions.
“…Moreover, the appearance of shoulder peak B at 8985 eV indicates that the configuration of copper extracts in organic phases is plane square because the electron of s-orbital can migrate to the z -direction of the p-orbital with an empty state (1s → 4p z ). Similar spectral signatures were also observed for copper complexes with the plane square configuration . From these symmetry indications, the structural sketch of copper extracts drawn in Figure may be supposed.…”
Section: Resultssupporting
confidence: 71%
“…Compared with the case of tetraamminecopper(II), the XANES feature of the extracted copper complexes in organic phases is evidently different because of the chelate effect and conjugation effect of β-diketone ligands. This phenomenon was also reported for the structure of other tetracoordinated copper species . For instance, Chaboy et al investigated the coordination structure of four nitrogen-containing ligands (ammonia, ethylenediamine, phthalocyanine, and glycine) with copper(II) by X-ray absorption spectroscopy.…”
Section: Resultssupporting
confidence: 54%
“…This phenomenon was also reported for the structure of other tetracoordinated copper species. 26 For instance, Chaboy et al investigated the coordination structure of four nitrogen-containing ligands (ammonia, ethylenediamine, phthalocyanine, and glycine) with copper(II) by X-ray absorption spectroscopy. They found that although four copper species are tetracoordinated structure, their XANES features are evidently different, indicating the structure and property of ligands have pronounced effect on the geometry of coordinated ions.…”
Section: Resultsmentioning
confidence: 99%
“…Similar spectral signatures were also observed for copper complexes with the plane square configuration. 26 From these symmetry indications, the structural sketch of copper extracts drawn in Figure 2 1. There is no distinct difference on the parameters for inner-sphere coordination of copper extracts.…”
A microscopic investigation on the extraction process of copper(II) in ammoniacal solutions has been performed by X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculation. The structural change of copper(II) species in ammoniacal solution has been derived from X-ray absorption near-edge spectroscopy (XANES) by principal component analysis and linear combination fitting. It was found that the coordination structure of the extracted copper complex in the organic phases is planar square and independent of the aqueous pH, whereas the geometries of copper(II) species in ammoniacal solutions changed from axially elongated octahedron to distorted planar square with increase of pH. The coordination geometry and structural parameters of copper(II) species were further obtained by extended X-ray absorption fine structure (EXAFS) fitting and DFT calculation with the B3LYP functional. These results reveal that the formation of tetracoordinated copper(II) ammine species can evidently inhibit the copper extraction reaction. Thus, the extraction mechanism of copper(II) in ammoniacal solutions has been elucidated in view of the microscopic structural aspects of copper species in both organic phase and ammoniacal solutions.
“…The strong affinity of this molecule to the external walls of carbon nanotubes was shown in ref , where it was used to obtain copper-coated CNTs. Such (acac) 2 compounds with various metal ions possess unique physical and chemical properties, permitting their application as analytical reagents, catalysts, or inhibitors for many chemical reactions …”
The encapsulation of an organometallic paramagnetic molecule, copper(II) acetylacetonate (Cu(acac)2), inside single-walled carbon nanotubes (SW CNTs) is studied using continuous wave electron paramagnetic resonance (EPR). By preparing samples from fully opened as well as from closed SW CNTs, the EPR spectra of encapsulated and nonencapsulated molecules can be clearly identified. The EPR spectrum originating from the encapsulated molecules is unchanged by dispersion of the endohedral nanohybrids in a solvent or by solubilization of the nanohybrids in water using bile salt surfactants, demonstrating that the CNTs protect them from changes in their external environment. The EPR parameters obtained for the encapsulated molecules show that they experience an extremely apolar environment. From the dipolar broadening of the EPR lines of the nanohybrids, the distances between the encapsulated molecules inside the CNTs can be estimated by adapting Van Vleck’s method of moments for the case of a one-dimensional array of molecules. Furthermore, a combination of orientation dependent EPR experiments and polarized Raman scattering on preferentially aligned CNT hybrids in stretched polymer film samples yields information on the orientational distribution of the encapsulated molecules inside the SW CNTs.
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