Polarized spectroscopy and polarized UV light-induced molecular orientation of chiral diphenyl Schiff base Ni(ii) and Cu(ii) complexes and azobenzene in a PMMA film

Abstract

We have investigated polarized UV light-induced molecular orientation, namely increasing optical anisotropy of chiral diphenyl Schiff base Ni(II) and Cu(II) complexes (diph(SS)Ni and diph(SS)Cu) as well as azobenzene (AZ), as organic/inorganic hybrid materials in polymethylmethacrylate (PMMA) cast films. The driving force and reason for polarized UV light-induced molecular orientation of AZ are the so-called Weigert effect and accompanying molecular alignment of diph(SS)Ni or diph(SS)Cu is attributed to intermolecular interactions between two components dispersed in a flexible matrix environment of PMMA, which is confirmed with CD spectra. Gradual increase of the degree of dichroism was measured with polarized absorption electronic spectra. The anisotropic parameters were evaluated from them and were discussed based on interactions between electric transition dipole moments calculated by TD-DFT.