The interplay of configuration and conformation in helical perylenequinones: Insights from chirality induction in liquid crystals and calculations

Abstract

SummaryThe chirality transfer in liquid crystals induced by two helical perylenequinones (namely, the natural compounds cercosporin and phleichrome) was investigated by integrating measurements of helical twisting power with a conformational analysis by DFT calculations and with the prediction of their twisting ability by the surface-chirality method. The two quasi-enantiomeric derivatives induce oppositely handed cholesteric phases when introduced as dopants in nematic solvents. We evaluated the role of the different conformations of the chiral hydroxyalkyl side chains in determining the helical twisting power: They were found to affect the strength of the chirality transfer, although the handedness of the induced cholesteric phase is essentially determined by the axial chirality (helicity) of the core of the perylenequinones.

Chiral Dopants Derived from Ephedrine/Pseudoephedrine: Structure and Medium Effects on the Helical Twisting Power

“…Different model approaches for the prediction of the twisting ability have been applied and the results were compared with experimentally measured HTP values [10,11]. But reliable structureproperty correlations could only be found within dopant classes of similar molecular structures [12,13]. Anyway, such studies could be essential building blocks for a generally valuable perception allowing the preparation of tailor-made chiral mesogenic phases.…”