C
C stretching VCD signal
VCD spectroscopy was applied to allenic natural products to elucidate their axial chirality. The sign and intensity of C
C
C antistretching VCD signal were found to be affected by substituents on the allene.
Y, and X
Y
Z stretching region
VCD spectroscopy in the 1900–2400 cm−1 region has less often been studied. This article briefly summarises VCD studies in this spectral region and discusses the properties of 1900–2400 cm−1 chromophores.
The solution structure of the antibiotic vancomycin is studied in DMSO, allowing for a direct comparison of measurements done using Raman optical activity and vibrational circular dichroism. In this case, ROA wins!
A combination of visual inspection and machine learning is used to identify IR/VCD spectral markers to determine composition and absolute configuration of terpenes in complex mixtures.
VCD spectroscopy associated with DFT calculations is a powerful tool to unambiguously assign both the absolute configurations and conformations of chiral secondary metabolites directly in solution.