ChemInform Abstract: Design and Synthesis of New Ferroelectric Liquid Crystals. Part 5. Properties of Some Chiral Fluorinated FLCs: A Direct Connection Between Macroscopic Properties and Absolute Configuration in a Fluid Phase.

Abstract

ChemInform Abstract The basic correctness of the "bent cylinder binding site" model for packing in the smectic C* phase and its usefulness for stereochemical assignments are demonstrated. This recently proposed model for the molecular origins of the ferroelectric polarization P observed in chiral, layered, tilted liquid crystal phases such as smectic C* phase states that doping of a chiral compound (the guest) into a achiral (or low-polarization) C phase (the host) will afford orientation of the guest molecules such that measurement of P of the fluid mixture can establish the absolute configuration of the guest independently of any optical activity or crystallography measurements, a completely unique method for configurational assignments. Mixtures of host (IV) with 10% by weight of each guest (IIIa) and (IIIb) have P values of +2.8 and -17 nC/cm2, resp., thus demonstrating the absolute configuration of both (obtained from (I) in a 2:1 ratio at 0 rc C) on the one hand and predominant retention in the fluorination on the other. In contrast, fluorination of (V) proceeds with redominant inversion as is shown by the same method. The assignments are fully confirmed by conventional methods.