Strong effects of the matrix-environment on the MI-VCD spectra of chiral oxiranes trace back to depolarization effects arising from linear and circular birefringence and linear dichroism occurring within the anisotropic matrices.
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.
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.
The absolute configuration of cyclic peptides with two chiral centers can be unambiguously assigned with VCD. This is however not possible with three or four chiral centers. Hence, other techniques are needed to supplement VCD.
Strong solute–solvent interactions can affect VCD spectral signatures in various ways. In this perspective, we discuss the micro-solvation approach to simulate the solvent effects.