Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.249, 17-25, 1994
Liquid-Crystalline Paramagnetic Cu(II) Complexes of Enaminoketone Ligands
Studies of complexes : [R-C6H4-CO(CH)(2)N-Alk]Cu-2, (I), [Alk-CO(CH)(2)N-C6H4-R]Cu-2, (II), and [R(1)-C6H4-CO(CH)(2)N-C6H4-R(2)]Cu-2, (III), for various terminal substituents R, R(1), R(2), are presented. For alkyl substituents R, complexes are low-melting and low-clearing nematics (group (I)) and smectics A (group (II)). Mesophases are monotropic for pure compounds, enantiotropic for mixtures. Elongation of molecular core by introduction trans-cyclohexyl rings into R substituents leads to enantiotropic paramagnetic mesogens. Complexes of the group (III) are high-melting and high-clearing mesogens which usually undergo decomposition in the isotropic phase. Chiral highly twisted mesophases are observed for some optically active complexes.