Asymmetric Synthesis of (S)-2-Amino-3-(1-naphthyl)propanoic Acid via Chiral Nickel Complex. Crystal Structure, Circular Dichroism, 1H and 13C NMR Spectra of the Complex

2005 ◽  
Vol 70 (9) ◽  
pp. 1397-1410 ◽  
Author(s):  
Alexander Popkov ◽  
Ivana Císařová ◽  
Jana Sopková ◽  
Josef Jirman ◽  
Antonín Lyčka ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Asymmetric Synthesis ◽  
1H And 13C Nmr ◽  
X Ray ◽  
Complex Crystal Structure ◽  
Cotton Effects ◽  
Circular Dichroïsm ◽  
Complex Crystal ◽  
C Nmr

The recently published environmentally friendly preparation of a glycine synthon 2 from regeneratable chiral auxiliary BPB ((S)-N-(2-benzoylphenyl)-N'-benzylprolinamide) was used for preparative asymmetric synthesis of the non-coded amino acid 3-(1-naphthyl)alanine (1). Full assignment of 1H and 13C NMR of both intermediate complex 3 and 1 and X-ray structure determination of complex 3 were made. Cotton effects observed in circular dichroism spectrum of complex 3 are consistent with published empirical rules.

Element specific determination of the magnetic properties of two macrocyclic tetranuclear 3d–4f complexes with a Cu3Tb core by means of X-ray magnetic circular dichroism (XMCD)

2018 ◽  
Vol 20 (33) ◽  
pp. 21286-21293
Author(s):  
K. Balinski ◽  
L. Schneider ◽  
J. Wöllermann ◽  
A. Buling ◽  
L. Joly ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Circular Dichroism ◽  
Magnetic Structure ◽  
Magnetic Circular Dichroism ◽  
Macrocyclic Complexes ◽  
X Ray ◽  
Specific Determination ◽  
Circular Dichroïsm

We apply X-ray magnetic circular dichroism to study the internal magnetic structure of two very promising star shaped macrocyclic complexes with a CuII3TbIII core.

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

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.

X-RAY MAGNETIC CIRCULAR DICHROISM ON Pt L-EDGES IN Co-BASED MATERIALS

2005 ◽  
Vol 19 (30) ◽  
pp. 4517-4523 ◽  
Author(s):  
P. POULOPOULOS
Keyword(s):  
Circular Dichroism ◽  
Magnetic Moment ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Crystallographic Structure ◽  
Third Generation ◽  
X Ray ◽  
Fcc Lattice ◽  
Circular Dichroïsm

Progress in third-generation synchrotron radiation facilities has made possible, nowadays, the determination of induced spin and orbital magnetic moments of 5d transition metal elements via the element-specific X-ray magnetic circular dichroism technique. In this work, recent results on the magnetic moments of Pt in Co -based alloys and multilayers are briefly reviewed. The magnetic moment carried by the 5d electrons of Pt in these systems ranges between 0.2 and 0.7μ B /atom. The ratio of orbital μ L to spin μS magnetic moment is found to be in the range 0.15–0.25. Finally, a method is described for the determination of Pt magnetic moment in lattices other than the fcc lattice, which is the thermodynamically stable crystallographic structure of bulk Pt .

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