Four-unit linking groups V. Optically active dopants

A number of diesters incorporating a four-unit linking group in the acid part (3-propyloxy, (E)-3-propenyloxy, and 4-butyl units) and an optically active centre in the diol part have been prepared. Structurally related three and four ring dioxolanes derived from the corresponding aldehyde precursors to the acids (i.e., also containing 3-propyloxy, (E)-3-propenyloxy, and 4-butyl groups) and the optically active tartaric acids have also been synthesized. The physical properties of these potential chiral dopants pertinent to electrooptic display device and thermochromic applications have been determined. These new chiral dopants are characterized by short pitches, good solubility in nematic hosts, excellent chemical, photochemical and thermal stability, etc. Most of these new optically active substances are well suited for at least one potential application for a chiral nematic mesophase with exactly denned properties made from a standard nematic mesophase and an optically active dopant. A small number of the new substances exhibit mesomorphic properties at elevated temperatures.