Chirality induction and amplification in supramolecular systems exhibiting vibrational optical activity.

Abstract

Vibrational optical activity (VOA) refers to two vibrational techniques: vibrational circular dichroism (VCD) and Raman optical activity (ROA) that are sensitive both to the chirality and the molecular structure, typically surpassing electronic optical activity (EOA) in recognition of fine structural details. However, the measurement of VOA is inherently obstructed as the intensity of the VOA signal is typically 10-4-10-5 of the intensity of the parent IR or Raman signals. This feature considerably limits the practical applications of VOA and is a fundamental reason why various strategies are currently developed to enhance the VOA intensity. This perspective review discusses up-to-date studies focusing on applications of VOA to analyse supramolecular, mostly biogenic, systems showing induction and amplification of chirality. Most attention is devoted to two types of biogenic supramolecular assemblies providing unique enhancement of VOA: amyloid fibrils showing enormous VCD and carotenoid aggregates exhibiting resonantly enhanced ROA.