The magnetic circular dichroism (MCD) spectra of 8-hydroxyquinoline (oxine) in various solvents were measured for the
1L
b and
1L
a absorption bands. The MCD spectra of eleven metal oxinates were also measured for the ligand absorption bands. Oxine exhibited a characteristic MCD spectral feature for each molecular form, that is, cationic, anionic, neutral and zwitterionic forms. The property of metal-ligand bonding of metal oxinates was discussed by means of these MCD spectra. The MCD technique was demonstrated to be useful for investigating the metal-ligand bonding properties, and it was concluded that as for the metal-oxygen bonding, ionic character was dominant for Mg, Al Co, Fe, Ni, Cu and Zn oxinates and covalent character was dominant for V, Mo, Ag and Cd oxinates.
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