Bimetallomesogens: Synthesis and mesomorphic properties of coppercomplexes of 3,3′-(2-hydroxypropane-1,3-diyl)bis(azan-1-yl-1-ylidene)bis(2-(4- alkoxyphenyl)prop-1-en-1-ol)

A new type of 3,3′-(2-hydroxypropane-1,3-diyl) bis(azan-1-yl-1- ylidene)bis(2-(4-alkoxy phenyl)prop-1-en-1-ol) and their copper complexes were prepared and mesomorphic properties characterized. The mesomorphic properties of these copper complexes were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and powder X-ray diffraction. X-ray structural crystallographic analysis showed that these bimetallic compounds have two copper centers coordinated with central square planar geometry. These molecules all have total two 1a or five alkoxy sidechains 1b appended around the central core. The mesomorphic behavior exhibited was found to be dependent on the sidechain density. All compounds in 1a exhibited smectic mesophases, however, compounds in 1b exhibited hexagonal columnar phases (Col_h), which were characterized by optical textures and confirmed by powder x-ray diffraction.