Improvement of the dopant compatibility in a chiral LC mixture by structural modification of lanthanide complexes

Abstract

The syntheses of Eu³⁺‐ and Nd³⁺‐cholesterol derivative complexes are described. All complexes have been characterized by ¹H NMR, ¹³C{¹H} NMR, IR spectroscopies and elemental analysis. They have been incorporated in various amounts into chiral LC mixtures. The influence of the complex's shape, the alkyl chain length and the dopant concentration on the phase transition temperatures of these rare earth‐doped liquid crystals was investigated. Lanthanide dopants with calamitic cholesteryl ester ligands were mixed in the chiral LC at a level of 6 mol % without altering the liquid crystal texture.

Acknowledgments

We thank the Ministère chargé de la Recherche, the Région Nord‐Pas‐de‐Calais and the Fonds Européen de Développement Economique des Régions for their financial support, and Pr. Patrick Martin for help in recording IR data.