| 日時: |
2013-04-09 13:30 - 15:30 |
| 場所: |
4号館2階輪講室1 東海1号館324室 |
| 会議名: |
物構研談話会（13-01）In Search of the Best Synchrotron Facility for Multi-Edge X-ray Absorption Spectroscopy: Electronic Structure from XANES and Geometric Structure from EXAFS |
| 連絡先: |
阿部仁4972 |
| 講演者: |
Dr. Robert K. Szilagyi (Department of Chemistry and Biochemistry, Montana State University) |
| アブストラクト: |
Multi-edge X-ray Absorption Spectroscopy is a powerful approach to obtain direct experimental information about the electronic and geometric structures of transition metal complexes with unoccupied d-orbital manifolds. X-ray Absorption Near Edge Spectroscopic measurements and molecular orbital-based analysis of pre-edge and rising-edge features can provide information about the orbital contribution and effective nuclear charge of an absorber. These are key electronic structural informations to define quantitatively the degree of covalent and ionic interactions involving the absorber. Data obtained in the energy range of hard, tender, and soft X-rays provide metal p, ligand p and metal d for third row main group elements and second row transition metals, and metal d and ligand p for first row transition metals and second row main group elements, respectively. The multi-edge Extended Absorption Fine Structure analysis has the potential to define atomic positional coordinates for non-crystalline samples with accuracy that is comparable to small molecule crystallography.
The presentation will highlight case studies to demonstrate the power of using multi-edge XAS measurements through examples obtained from the beamlines of Stanford Synchrotron Radiation Lightsource in Menlo Park CA, Advanced Light Source in Berkeley CA, Synchrotron Research Center in Stoughton WI, and the Canadian Light Source in Saskatoon Canada. Transition metal complexes studied will include biomimetic compounds of FeFe-hydrogenase metalloenzyme, non-innocent Cu and Ni pincer type complexes, precatalysts for Pd-based homogeneous organometallic reactions.
Key references:
Rokhsana D., Howells A.E., Dooley D.M., Szilagyi R.K.:
Role of the Tyr-Cys Cross-link to the Active Site Properties of
Galactose Oxidase
Inorganic Chemistry, 2012, 51(6), 3513-3524
Giles L.J., Grigoropoulos A., Szilagyi R.K.:
Multi-Edge X-Ray Absorption Spectroscopy Part I: XANES Analysis of a
Biomimetic Model of FeFe-Hydrogenase
Journal of Physical Chemistry A, 2012, 116(50), 12280-12298
Queen M.S., Towey B.D., Murray K.A., Veldkamp B.S., Byker H.J., Szilagyi R.K.:
Electronic Structure of [Ni(II)S4] Complexes from S K-edge X-ray
Absorption Spectroscopy
Coordination Chemistry Reviews, 2013, 257(2), 564-578
Mossin S., Tran B.L., Adhikari D., Pink M., Heinemann F.W., Sutter J.,
Szilagyi RK, Meyer K., Mindiola D.J.
A Mononuclear Fe(III) Single Molecule Magnet with a 3/2 <-> 5/2 spin crossover
The Journal of American Chemical Society, 2012, 134(33), 13651-13661 |
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