SPECTROSCOPIC AND ODMR INVESTIGATIONS OF THE LOWEST PI-PI-ASTERISK AND LIGAND-LIGAND CHARGE-TRANSFER EXCITED-STATES OF ZINC(II) MIXED-LIGAND COMPLEXES

Zero-field splittings of the emitting levels of the title compounds were measured by ODMR. For complexes of the type Zn(X-PhS)2(phen) resonances of the 3-pi-pi-* phosphorescing levels were observed for X = F5,4-Cl, 4-CH3. For X = 4-Cl, resonances were detected for the 3LLCT emitting manifold also. For X = 4-CH30, resonances were detected only for the 3LLCT emitting states. A model invoking mixing between the two types of states is proposed that satisfactorily accounts for the dependences of the properties of the emitting manifolds on the donating ability of the X substituent.