Polarized light-induced molecular orientation control of rigid schiff base Ni(II), Cu(II), and Zn(II) binuclear complexes as polymer composites

We have investigated linearly polarized UV light-induced molecular orientation due to Weigert effect of composite materials of new six binuclear nickel(II), copper(II), and zinc(II) complexes of two rigid Schiff base ring ligands (L₁ and L₂) composite materials with methyl orange (MO), an azo-dye, in polyvinylalchol (PVA) cast films. To compare the degree of molecular orientation, two ligands, namely flexible aliphatic cyclohexane (ML₁: NiL₁, CuL₁, ZnL₁) and rigid aromatic (ML₂: NiL₂, CuL₂, ZnL₂), were synthesized using amine moiety.We have also characterized these complexes by means of elemental analysis, IR, and UV-vis spectra, single crystal or powder X-ray diffraction (XRD) analysis, and so on. Composite materials of ML₁ or ML₂+MO+PVA were also prepared to separately disperse the solutes in a polymer matrix. For any metal complexes, optical anisotropy (represented as the R parameters) of ML₂+MO+PVA was larger than ML₁+MO+PVA because of the rigidness of the ligands.