Abstract
A microscopic model for interpreting remarkably high helical twisting power (HTP) of metal complexes as a chiral dopant is proposed. The intermolecular interaction of a triad system consisting of a dopant and two host molecules located near its chiral center has been calculated for this purpose. The dopant molecule studied here is D-[M(acac)2L] (L= dibenzoylmethanate substituted with n octyloxy groups), and the host molecule is N-(4-methoxybenzylidene)-4-n-butylaniline (MBBA). D-[M(acac)2L] is regarded as a modified three-bladed propeller, interacting with host molecules through its bulky ligands. The stable structure has been obtained by geometry optimization using Gaussian 03, and the interaction energy assessed as a function of twisting angle between two host molecules. The results provide a simple explanation for the extremely high HTP as observed for this type of a chiral dopant.
