Physical mechanism and electric-magnetic interaction in ECD and ROA: Visualization methods on chirality

Abstract

Many receptors in existence are composed of chiral molecules. So, chirality is one of the structural features of chemical and biological organic molecules. The role of chirality is mainly reflected in the identification and the corresponding reaction mechanism of molecular species. In this paper, we perform an intuitive visual analysis of the new nor-BPAP (bicyclic polyprenylated acylphloroglucinols) derivatives. The physical nature of this molecule and chirality is studied and analyzed by combining the two-dimensional (2D) map and three-dimensional (3D) map of its excited state. We characterize the transition magnetic dipole moment (TMDM), the transition electric dipole moment (TEDM), the transition electric quadrupole moment (TEQM), and their tensor product. In this way, the electrical and magnetic interactions can be well visually analyzed. During the process, the anisotropy of the TEDM/TMDM is derived from different chiral centers in the molecule. At the same time, the relationship among molecular vibration mode, molecular Raman optical activity (ROA) and the molecular chiral structure is also analyzed. The ROA spectrum reverses because the group responses based on different vibration modes of the chiral molecules.