Paramagnetic liquid-crystalline complexes based on novel enaminoketone ligands

Calamitic ligands having aminopropenone-3 ring substituted with alkyl-trans-cyclohexyl-phenyl and alkyl groups are low melting nematogens. Copper(II) complexed to the ligands gives thermally stable rod-like liquid crystals which exhibit an enantiotropic paramagnetic nematic phase. It is shown that modifications of the terminal groups as well as synthesis of asymmetric complexes enables us to extend the nematic range and depress the melting points.