A vibrational circular dichroism (VCD) methodology for the measurement of enantiomeric excess in chiral compounds in the solid phase and for the complementary use of NMR and VCD techniques in solution: the camphor case

The Analyst ◽  
2018 ◽  
Vol 143 (6) ◽  
pp. 1406-1416 ◽  
Author(s):  
María Mar Quesada-Moreno ◽  
Albert Virgili ◽  
Eva Monteagudo ◽  
Rosa M. Claramunt ◽  
Juan Ramón Avilés-Moreno ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Solid Phase ◽  
Enantiomeric Excess ◽  
Vibrational Circular Dichroism ◽  
Solid Samples ◽  
Chiral Compounds ◽  
First Time ◽  
Circular Dichroïsm

For the first time, it is shown that VCD spectroscopy can be used to determine the % ee in chiral solid samples.

Determination of Enantiomeric Excess in Deuterated Chiral Hydrocarbons by Vibrational Circular Dichroism Spectroscopy

1990 ◽  
Vol 44 (2) ◽  
pp. 235-238 ◽  
Author(s):  
Kevin M. Spencer ◽  
Steven J. Cianciosi ◽  
John E. Baldwin ◽  
Teresa B. Freedman ◽  
Laurence A. Nafie
Keyword(s):  
Circular Dichroism ◽  
Enantiomeric Excess ◽  
Circular Dichroism Spectroscopy ◽  
Vibrational Circular Dichroism ◽  
Circular Dichroïsm

Substituent effect in theoretical VCD spectra

RSC Advances ◽  
2014 ◽  
Vol 4 (51) ◽  
pp. 27062-27066 ◽  
Author(s):  
Piotr F. J. Lipiński ◽  
Jan Cz. Dobrowolski
Keyword(s):  
Circular Dichroism ◽  
Substituent Effect ◽  
Vibrational Circular Dichroism ◽  
Correlational Study ◽  
First Time ◽  
Circular Dichroïsm

A correlational study shows for the first time a quantitative substituent effect on Vibrational Circular Dichroism intensity.

scholarly journals Solid Phase Nitrosylation of Enantiomeric Cobalt(II) Complexes

Chemistry ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 585-597
Author(s):  
Mads Sondrup Møller ◽  
Morten Czochara Liljedahl ◽  
Vickie McKee ◽  
Christine J. McKenzie
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Atmospheric Pressure ◽  
Solid Phase ◽  
Cobalt Complexes ◽  
Vibrational Circular Dichroism ◽  
Chiral Induction ◽  
Solution State ◽  
Circular Dichroïsm ◽  
Salen Ligand

Accompanied by a change in color from red to black, the enantiomorphic phases of the cobalt complexes of a chiral salen ligand (L2−, Co(L)·CS2, and Co(L) (L = LS,S or LR,R)) chemisorb NO (g) at atmospheric pressure and rt over hours for the CS2 solvated phase, and within seconds for the desolvated phase. NO is installed as an axial nitrosyl ligand. Aligned but unconnected voids in the CS2 desorbed Co(LR,R)·CS2 structure indicate conduits for the directional desorption of CS2 and reversible sorption of NO, which occur without loss of crystallinity. Vibrational circular dichroism (VCD) spectra have been recorded for both hands of LH2, Zn(L), Co(L)·CS2, Co(L), Co(NO)(L), and Co(NO)(L)·CS2, revealing significant differences between the solution-state and solid-state spectra. Chiral induction enables the detection of the νNO band in both condensed states, and surprisingly also the achiral lattice solvent (CS2 (νCS at 1514 cm−1)) in the solid-state VCD. Solution-state spectra of the paramagnetic Co(II) complex shows a nearly 10-fold enhancement and more extensive inversion of polarity of the vibrations of dominant VCD bands compared to the spectra of the diamagnetic compounds. This enhancement is less pronounced when there are fewer polarity inversions in the solid state VCD spectra.

Enantiomeric Excess Determination by Fourier Transform Near-Infrared Vibrational Circular Dichroism Spectroscopy: Simulation of Real-Time Process Monitoring

2005 ◽  
Vol 59 (9) ◽  
pp. 1114-1124 ◽  
Author(s):  
Changning Guo ◽  
Rekha D. Shah ◽  
Rina K. Dukor ◽  
Xiaolin Cao ◽  
Teresa B. Freedman ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Circular Dichroism ◽  
Real Time ◽  
Near Infrared ◽  
Fractional Composition ◽  
Enantiomeric Excess ◽  
Flow Cell ◽  
Vibrational Circular Dichroism ◽  
Chiral Molecules ◽  
Circular Dichroïsm

The first use of near-infrared (NIR) Fourier transform vibrational circular dichroism (FT-VCD) to follow changes in the enantiomeric excess (EE) of chiral sample molecules in time using a flow-cell sampling apparatus is reported. Simultaneous changes in the fractional composition and the EE of a mixture of two different chiral molecules were monitored as a function of time. This simulates the progress of the chemical reaction from a chiral reactant to a chiral product where the mole fractions and EE values of both species may change with time. For the molecules studied, α-pinene, camphor, and borneol, the accuracy of following EE changes for one species alone is approximately 2%, while for simultaneously following EE changes in two species it is approximately 3% for 30 min sampling periods at 16 cm−1 spectral resolution. These findings demonstrate the potential for VCD to be used in the NIR region for real-time monitoring of the composition and %EE of chemical reactions involving the synthesis of chiral molecules.

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