ABSTRACT A large Faraday rotation characterized by a Verdet constant on the order of 10 6 o /T·m has been observed at room temperature in thin layers of discotic copper (Cu 2+ : 3 d 9 ) and vanadyl (VO 2+ : 3 d 1 ) enaminoketone complexes. Contrary to expectations, this remarkably high Verdet constant is not associated with electronic transitions in the inner shells of the metal ions, which typically occur at energies below 2.5 eV. Instead, the rotation increases with rising optical absorption at higher energies. Density‐functional theory (DFT) calculations indicate that the optical absorption in these discotic complexes arises from anisotropic transitions involving the π‐orbitals of the enaminoketone ligands. Moreover, the magnitude of the Verdet constant depends strongly on the molecular orientation of the discotic liquid crystals relative to the magnetic field direction. This orientation dependence highlights the potential for tunable Faraday rotation, achieved either through self‐assembly on surfaces or by external control, such as electric fields capable of reorienting the molecules.
Łempicka‐Mirek et al. (Wed,) studied this question.