The electronic structure and bond properties of the compartmental ligand 6, 11-dimethyl-7, 10-diazahexadeca-5, 11-diene-2, 4, 13, 15- tetraone (H~4daaen) and its mononuclear and binuclear compartmental complexes of [copper(II) and europium(III)] have been investigated by X-ray photoelectron spectroscopy (XPS). The changes of binding energy indicate the existence of distinct charge transfer phenomena in ligand molecules after the ligands forming the mononuclear complexes. The charge transfers from oxygen atoms to nitrogen atoms via π-bond in the ligand molecule when Cu(II) ion is coordinated and from nitrogen atoms to oxygen atoms when Eu(III) ion is coordinated. After the Cu(II) ion and Eu(III) ion are both coordinated, the charge transfer phenomenon is not obvious. The 2p~3~/~2 satellite phenomenon of Cu(II) is too complex to be explained by a single final- state screening theory.

Key words: COPPER COMPLEX, EUROPIUM COMPLEX, X-RAY PHOTOELECTRON SPECTROMETRY, CHARGE TRANSFER, NITROGEN HETEROCYCLICS, KETENE