XANES spectra of copper(II) complexes: correlation of the intensity of the 1s .fwdarw. 3d transition and the shape of the complex

Sano, Mitsuru; Komorita, Seiko; Yamatera, Hideo

doi:10.1021/ic00029a022

Cited by 102 publications

(128 citation statements)

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“…[13] The XANES signatures differ between the two Cu II species, as indicated by more intense B and D peaks and less-pronounced A and C peaks for [Cu…”

Section: X-ray Absorption Spectroscopy (Xas)mentioning

confidence: 99%

“…region is also affected. To better probe the coordination mode of the additional glycine amino acid, we have used different isotopically labelled glycine ( 15 N on the amine group or 13 C either on the carboxylate group or on the C a ). The superhyperfine structure observed for the 15 N-labelled glycine differs sufficiently from that of the unlabelled sample to support binding through the amine function.…”

Section: X-ray Absorption Spectroscopy (Xas)mentioning

confidence: 99%

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X‐ray and Solution Structures of Cu^IIGHK and Cu^IIDAHK Complexes: Influence on Their Redox Properties

Hureau

Eury

Guillot

et al. 2011

Chemistry A European J

134

204

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The Gly-His-Lys (GHK) peptide and the Asp-Ala-His-Lys (DAHK) sequences are naturally occurring high-affinity copper(II) chelators found in the blood plasma and are hence of biological interest. A structural study of the copper complexes of these peptides was conducted in the solid state and in solution by determining their X-ray structures, and by using a large range of spectroscopies, including EPR and HYSCORE (hyperfine sub-level correlation), X-ray absorption and (1)H and (13)C NMR spectroscopy. The results indicate that the structures of [Cu(II)(DAHK)] in the solid state and in solution are similar and confirm the equatorial coordination sphere of NH(2), two amidyl N and one imidazole N. Additionally, a water molecule is bound apically to Cu(II) as revealed by the X-ray structure. As reported previously in the literature, [Cu(II)(GHK)], which exhibits a dimeric structure in the solid state, forms a monomeric complex in solution with three nitrogen ligands: NH(2), amidyl and imidazole. The fourth equatorial site is occupied by a labile oxygen atom from a carboxylate ligand in the solid state. We probe that fourth position and study ternary complexes of [Cu(II)(GHK)] with glycine or histidine. The Cu(II) exchange reaction between different DAHK peptides is very slow, in contrast to [Cu(II)(GHK)], in which the fast exchange was attributed to the presence of a [Cu(II)(GHK)(2)] complex. The redox properties of [Cu(II)(GHK)] and [Cu(II)(DAHK)] were investigated by cyclic voltammetry and by measuring the ascorbate oxidation in the presence of molecular oxygen. The measurements indicate that both Cu(II) complexes are inert under moderate redox potentials. In contrast to [Cu(II)(DAHK)], [Cu(II)(GHK)] could be reduced to Cu(I) around -0.62 V (versus AgCl/Ag) with subsequent release of the Cu ion. These complete analyses of structure and redox activity of those complexes gave new insights with biological impact and can serve as models for other more complicated Cu(II)-peptide interactions.

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“…[13] The XANES signatures differ between the two Cu II species, as indicated by more intense B and D peaks and less-pronounced A and C peaks for [Cu…”

Section: X-ray Absorption Spectroscopy (Xas)mentioning

confidence: 99%

Section: X-ray Absorption Spectroscopy (Xas)mentioning

confidence: 99%

X‐ray and Solution Structures of Cu^IIGHK and Cu^IIDAHK Complexes: Influence on Their Redox Properties

Hureau

Eury

Guillot

et al. 2011

Chemistry A European J

134

204

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“…Its intensity is determined by the admixture of p-orbital contributions. Therefore, it is sensitive to the local symmetry at the Cu center and increases when going from a quadratic-planar to a tetrahedral coordination geometry [41].…”

Section: Discussionmentioning

confidence: 99%

“…7d). These differences in the dipole intensity can be directly related to the coordination geometry and the local symmetry at the Cu center [41].…”

Section: Mo Analysis Of the Calculated Xas Spectra For Copper(ii) Commentioning

confidence: 99%

Revisiting the Dependence of Cu K-Edge X-Ray Absorption Spectra on Oxidation State and Coordination Environment

Rudolph¹,

Jacob²

2018

Preprint

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X-ray absorption spectroscopy (XAS) at the Cu K-edge is an important tool for probing the properties of copper centers in transition metal chemistry and catalysis.However, the interpretation of experimental XAS spectra requires a detailed understanding of the dependence of spectroscopic features on the local geometric and electronic structure, which can be established by theoretical X-ray spectroscopy.Here, we present a systematic computational study of the Cu K-edge XAS spectra of selected Cu complexes based on time-dependent density-functional theory in combination with a molecular orbital analysis of the relevant transitions. For a series of Cu ammine model complexes as well as a comprehensive test set of 12 Cu(I) and 5 Cu(II) complexes, we revisit the dependence of the pre-edge region in Cu K-edge XAS spectra on oxidation state and coordination geometry. While our calculations confirm earlier experimental assignments, we can also reveal additional signatures of the ligand orbitals and identify the underlying orbital interactions.The comprehensive picture provided by this study will provide a reliable basis for the interpretation of in situ Cu K-edge XAS spectra of catalytic intermediates.2

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“…The weak pre-edge at 8.979 keV arises from the quadrupole-allowed 1s  3d transition, which is only prominent in absence of inversion symmetry. 52,53 The shoulder M 1 at 8.992 eV and the peak M 2 at 8.997 eV are assigned respectively to the 1s4pz and to the 1s 4px,y transitions. The broad peak B around 9 eV is caused by multiple scattering of the photoelectron within the first coordination shell of Cu II 54,55 so that its energy position indirectly depends upon the Cu II -N bond length.…”

Section: Spectroscopic Characterizations Of Cumentioning

confidence: 99%

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

et al. 2016

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Metalloporphyrins are prominent building blocks in the synthetic toolbox of advanced photodriven molecular devices. When the central ion is paramagnetic, the relaxation pathways within the manifold of excited states are highly intricate so that unravelling the intramolecular energy and electron transfer processes is usually a very complex task. This fact is critically hampering the development of applications based on the enhanced coupling offered by the electronic exchange interaction. In this work, the dynamics of charge separation in a copper porphyrin-fullerene are studied with several complementary spectroscopic tools across the electromagnetic spectrum (from near infra-red to X-ray wavelengths), each of them providing specific diagnostics. Correlating the various rates clearly demonstrates that the lifetime of the photoinduced charge-separated state exceeds by about 10 fold that of the isolated photoexcited Cu II porphyrin. As revealed by the spectral modifications in the XANES region, this stabilization is accompanied by a transient change in covalency around the Cu II center, which is induced by an enhanced interaction with the C 60 moiety. This experimental finding is further confirmed by state-of-the art calculations using DFT and TD-DFT including dispersion effects that explain the electrostatic and structural origins of this interaction, as the Cu II P cation becomes ruffled and approaches closer to the fullerene in the charge-separated state. From a methodological point of view, these results exemplify the potential of multielectron excitation features in transient X-ray spectra as future diagnostics of sub-femtosecond electronic dynamics. From a practical point of view, this work is paving the way for elucidating out-ofequilibrium electron transfer events coupled to magnetic interaction processes on their intrinsic time-scales.

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XANES spectra of copper(II) complexes: correlation of the intensity of the 1s .fwdarw. 3d transition and the shape of the complex

Cited by 102 publications

References 0 publications

X‐ray and Solution Structures of Cu^IIGHK and Cu^IIDAHK Complexes: Influence on Their Redox Properties

X‐ray and Solution Structures of Cu^IIGHK and Cu^IIDAHK Complexes: Influence on Their Redox Properties

Revisiting the Dependence of Cu K-Edge X-Ray Absorption Spectra on Oxidation State and Coordination Environment

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

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XANES spectra of copper(II) complexes: correlation of the intensity of the 1s .fwdarw. 3d transition and the shape of the complex

Cited by 102 publications

References 0 publications

X‐ray and Solution Structures of CuIIGHK and CuIIDAHK Complexes: Influence on Their Redox Properties

X‐ray and Solution Structures of CuIIGHK and CuIIDAHK Complexes: Influence on Their Redox Properties

Revisiting the Dependence of Cu K-Edge X-Ray Absorption Spectra on Oxidation State and Coordination Environment

Elucidating the Ultrafast Dynamics of Photoinduced Charge Separation in Metalloporphyrin-Fullerene Dyads Across the Electromagnetic Spectrum

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Product

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X‐ray and Solution Structures of Cu^IIGHK and Cu^IIDAHK Complexes: Influence on Their Redox Properties

X‐ray and Solution Structures of Cu^IIGHK and Cu^IIDAHK Complexes: Influence on Their Redox Properties