Induced Cholesteric Mesophases as a Probe for the Stereochemistry of Chiral Biphenyls

In the studies of the induced cholesteric mesophases, the twisting powers of cisoid- and transoidbridged 2,2′-diaminobiphenyl derivatives having R-configuration were found to be negative and positive respectively. In the cases where CD spectroscopy is inadequate, the liquid crystal method is sensitive to the helicity of the biphenyl moiety. The conformation of 2,2′-diamino-6,6′-dimethylbiphenyl is discussed.