Absolute Configuration by X-ray and Circular Dichroism Methods of Calycanthine

1973 ◽  
Vol 244 (132) ◽  
pp. 30-32 ◽  
Author(s):  
A. F. BEECHAM ◽  
A. C. HURLEY ◽  
A. McL. MATHIESON ◽  
J. A. LAMBERTON
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
X Ray ◽  
Circular Dichroïsm

Conclusive Determination of the Absolute Configuration of Chiral C60-Fullerenecis-3 Bisadducts by X-ray Crystallography and Circular Dichroism

2005 ◽  
Vol 117 (15) ◽  
pp. 2302-2305 ◽  
Author(s):  
Shunsuke Kuwahara ◽  
Kazuhiro Obata ◽  
Kazuhiro Yoshida ◽  
Takatoshi Matsumoto ◽  
Nobuyuki Harada ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Absolute ◽  
Circular Dichroïsm

Absolute configuration of Tröger bases: an X-ray diffraction and circular dichroism study

2006 ◽  
Vol 47 (3) ◽  
pp. 319-321 ◽  
Author(s):  
Denis A. Lenev ◽  
Konstantin A. Lyssenko ◽  
Denis G. Golovanov ◽  
Oleg R. Malyshev ◽  
Pavel A. Levkin ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Circular Dichroïsm

scholarly journals X-ray Natural Circular Dichroism

2014 ◽  
Vol 70 (a1) ◽  
pp. C1518-C1518
Author(s):  
Andrei Rogalev ◽  
Alexei Bosak ◽  
Fabrice Wilhelm ◽  
Jose Goulon
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Electric Dipole ◽  
Electric Quadrupole ◽  
Interference Term ◽  
Opposite Parity ◽  
X Ray ◽  
Determination Of Absolute Configuration ◽  
Circular Dichroïsm

Natural Circular Dichroism was only recently discovered in the x-ray range[1]. This effect stems from the interference terms which mix multipole transition moments of opposite parity: the Electric Dipole-Electric Quadrupole (E1.E2) and the Electric Dipole-Magnetic Dipole (E1.M1) exist only in structures with broken space inversion symmetry. The scalar E1.M1 term known to be responsible for Circular Dichroism at optical wavelengths is usually considered to be vanishingly small for core level spectroscopies. The E1.E2 interference term, on the contrary, can be large in the X-ray region, but it is a parity odd second rank tensor and therefore observable only in 13 non-centrosymmetric crystal classes. X-ray Natural Circular Dichroism has now been detected in the XANES region for several uniaxial and biaxial crystals. It can give access to the absolute configuration of chiral absorbing centers. On the other hand, Chiral-EXAFS, i.e. the analog of Magnetic-EXAFS for Natural Circular Dichroism has also been measured recently using a uniaxial optically active crystal of paratellurite (TeO2). Chiral-EXAFS originates from symmetry allowed multiple scattering paths. In this presentation, we wish to report on recent advances in X-ray natural circular dichroism and its applications. Determination of absolute configuration is illustrated with measurements of both E1.E2 and E1.M1 terms in chiral alpha-Ni(H2O)6·SO4 single crystals. Manifestation of X-ray optical acitivity in magnetoelectric crystals will be illustrated with various dichroisms measured at the Fe K-edge in multiferroic GaFeO3 crystal. Finally, we will review briefly the perspectives open by our experiments.

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