Matrix effects in MI-VCD spectra of two chiral oxiranes and their potential microscopic origin

Abstract

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.

Vibrational Circular Dichroism of a Chiral Triplet Nitrene Investigated Under Matrix‐Isolation Conditions in Parahydrogen

“…However, despite attempting various matrix deposition conditions, the experimental MI–VCD spectra were severely distorted by artefacts. These artefacts were similar to those observed for other rather flat molecules, and reasoned to arise from scattering effects due to micro‐crystalline packing behavior of the host gas under deposition conditions [19] . To circumvent such effects, we implemented a MI–VCD setup, that allowed us to use para‐hydrogen as matrix host gas.…”

“…These artefacts were similar to those observed for other rather flat molecules, and reasoned to arise from scattering effects due to micro-crystalline packing behavior of the host gas under deposition conditions. [19] To circumvent such effects, we implemented a MI-VCD setup, that allowed us to use para-hydrogen as matrix host gas. Parahydrogen (pH 2 ) is known to show great heat dissipation and favorable "self-healing" properties of the crystal lattice, [20] so that it was expected not to show any packing-related artefacts in VCD spectra.…”