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Title: XAFS Study of the Local Structure of Some Lanthanoid(III) Complexes

Abstract

Two types of lanthanoid(III) complexes were synthesized: type I complexes - Ln(III) (Ln = Sm, Eu, Tb, Dy) anthrarufinate complexes using anthrarufin (1,5-dihydroxy-9,10-anthraquinone) as the ligands, and type II complexes - Ln(III)-transition(d-bloch) metal(II) bi-nuclear complexes. The local structures of these complexes were studied by EXAFS spectroscopy. We found that there is a good linear correlation between the ionic radii of Ln(III) and the Ln-O distances for the type I complexes, and for type II complexes the interatomic distances between Gd and coordinated oxygen atoms of the bi-nuclear complex are shorter than those of the Gd mononuclear complex.

Authors:
;  [1];  [2]
  1. Department of Frontier Materials Chemistry, Faculty of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561 (Japan)
  2. Department of Advanced Physics, Faculty of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561 (Japan)
Publication Date:
OSTI Identifier:
21054649
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 882; Journal Issue: 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644552; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ANTHRAQUINONES; ATOMIC RADII; CORRELATIONS; DYSPROSIUM COMPLEXES; DYSPROSIUM IONS; FINE STRUCTURE; INTERATOMIC DISTANCES; IODINE COMPLEXES; LIGANDS; OXYGEN; RARE EARTH COMPOUNDS; SAMARIUM COMPLEXES; SAMARIUM IONS; X-RAY SPECTROSCOPY

Citation Formats

Sudoh, Susumu, Miyamoto, Ryo, and Miyanaga, Takafumi. XAFS Study of the Local Structure of Some Lanthanoid(III) Complexes. United States: N. p., 2007. Web. doi:10.1063/1.2644552.
Sudoh, Susumu, Miyamoto, Ryo, & Miyanaga, Takafumi. XAFS Study of the Local Structure of Some Lanthanoid(III) Complexes. United States. doi:10.1063/1.2644552.
Sudoh, Susumu, Miyamoto, Ryo, and Miyanaga, Takafumi. Fri . "XAFS Study of the Local Structure of Some Lanthanoid(III) Complexes". United States. doi:10.1063/1.2644552.
@article{osti_21054649,
title = {XAFS Study of the Local Structure of Some Lanthanoid(III) Complexes},
author = {Sudoh, Susumu and Miyamoto, Ryo and Miyanaga, Takafumi},
abstractNote = {Two types of lanthanoid(III) complexes were synthesized: type I complexes - Ln(III) (Ln = Sm, Eu, Tb, Dy) anthrarufinate complexes using anthrarufin (1,5-dihydroxy-9,10-anthraquinone) as the ligands, and type II complexes - Ln(III)-transition(d-bloch) metal(II) bi-nuclear complexes. The local structures of these complexes were studied by EXAFS spectroscopy. We found that there is a good linear correlation between the ionic radii of Ln(III) and the Ln-O distances for the type I complexes, and for type II complexes the interatomic distances between Gd and coordinated oxygen atoms of the bi-nuclear complex are shorter than those of the Gd mononuclear complex.},
doi = {10.1063/1.2644552},
journal = {AIP Conference Proceedings},
number = 1,
volume = 882,
place = {United States},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007}
}
  • Octakis(DMSO)lanthanoid(III) iodides (DMSO = dimethylsulfoxide), [Ln(OS(CH{sub 3}){sub 2}){sub 8}]I{sub 3}, of most lanthanoid(III) ions in the series from La to Lu have been studied in the solid state and in DMSO solution by extended X-ray absorption fine structure (EXAFS) spectroscopy. L{sub 3}-edge and also some K-edge spectra were recorded, which provided mean Ln-O bond distances for the octakis(DMSO)lanthanoid(III) complexes. The agreement with the average of the Ln-O bond distances obtained in a separate study by X-ray crystallography was quite satisfactory. The crystalline octakis(DMSO)lanthanoid(III) iodide salts have a fairly broad distribution of Ln-O bond distances, ca. 0.1 {angstrom}, with a fewmore » disordered DMSO ligands. Their EXAFS spectra are in excellent agreement with those obtained for the solvated lanthanoid(III) ions in DMSO solution, both of which show slightly asymmetric distributions of the Ln-O bond distances. Hence, all lanthanoid(III) ions are present as octakis(DMSO)lanthanoid(III) complexes in DMSO solution, with the mean Ln-O distances centered at 2.50 (La), 2.45 (Pr), 2.43 (Nd), 2.41 (Sm), 2.40 (Eu), 2.39 (Gd), 2.37 (Tb), 2.36 (Dy), 2.34 (Ho), 2.33 (Er), 2.31 (Tm), and 2.29 {angstrom} (Lu). This decrease in the Ln-O bond distances is larger than expected from the previously established ionic radii for octa-coordination. This indicates increasing polarization of the Ln{sup III}-O(DMSO) bonds with increasing atomic number. However, the S(1s) electron transition energies in the sulfur K-edge X-ray absorption near-edge structure (XANES) spectra, probing the unoccupied molecular orbitals of lowest energy of the DMSO ligands for the [Ln(OS(CH{sub 3}){sub 2}){sub 8}]{sup 3+} complexes, change only insignificantly from Ln = La to Lu. This indicates that there is no appreciable change in the ?-contribution to the S-O bond, probably due to a corresponding increase in the contribution from the sulfur lone pair to the bonding.« less
  • The preparation of phthalocyanine complexes of yttrium, samarium, gadolinium, ytterbium, and lutetium is reported. The PcLnAcO complex (Pc = phthalocyanine dianion and AcO = acetate anion) was found to act as the sensitizer for the photoreduction of methylviologen chloride (MVCl{sub 2}) in a methanol solution upon irradiation with visible light. On the basis of data from visible spectrophotometric studies and laser flash-photolysis studies, the observation is made that the photoreduction of metalophthalocyanine complexes proceeds via an oxidative process, and a reaction scheme is proposed. 15 refs., 2 figs.
  • We have studied the local structure around Co in YBa{sub 2}(Cu{sub 1{minus}{ital x}}Co{sub {ital x}}){sub 3}O{sub 7{minus}{delta}} {ital c}-axis oriented thin films with three different concentrations: {ital x}=0.07, 0.10, 0.17, and in a PrBa{sub 2}(Cu{sub 1{minus}{ital x}}Co{sub {ital x}}){sub 3}O{sub 7{minus}{delta}} thin film of concentration {ital x}=0.05 using the x-ray absorption fine structure (XAFS) technique. Data were collected at the Co {ital K} edge with polarizations both parallel and perpendicular to the film surface. We find that the oxygen neighbors are well ordered and shortened in comparison with YBCO Cu-O values to {approximately}1.80 A and 1.88 A in the {italmore » c} axis and {ital ab} plane, respectively. The data also show that there are approximately two O neighbors in the main Co-O peak for the {ital ab}-plane data, which agrees with a Cu(1) substitution site but is inconsistent with most of the Co on a Cu(2) site. A comparison of further neighbor peaks for the thin film and powder data show that the amplitude of these peaks is suppressed for the thin films relative to the powder samples. This suggests that there is more disorder and/or distortions of the Co environment present in the thin films. Since x-ray diffraction shows the films to be well ordered, this is a localized distortion. We also compared the polarized XAFS results with calculations for four oxides CoO, Co{sub 2}O{sub 3}, Co{sub 3}O{sub 4}, and CoBaO{sub 2}, and showed that the XAFS data are inconsistent with the presence of significant precipitates of these phases. {copyright} {ital 1996 The American Physical Society.}« less
  • The geometric structures for ferromagnetic Zn1-xCrxTe films grown by molecular beam epitaxy were investigated by fluorescence XAFS measurements in order to elucidate the relationship between the geometric structure and the magnetic properties. XAFS analysis suggested that the majority of Cr atoms doped in CrTe substituted the Zn-site in the ZnTe lattice below the Cr content x = 0.048, and formed Cr-Te compounds such as Cr2Te3 and CrTe above x = 0.090. It is suggested that ferromagnetism of the Zn1-xCrxTe films above x = 0.090 is due to the formation of Cr-Te compounds.