XPS study of the mononuclear and binuclear compartmental complexes of [copper(II) and europium(III)]

The electronic structrure and bond properties of the compartmental ligand 6 ,11-dimethyl-7, 10-diazahexadeca-5, 11-diene-2, 4, 13, 15-tetraone (H(4)daa en) and its mononuclear and binuclear compartmental complexes of [copper(II ) and europium(III)] have been investigated by X-ray photoelectron spectros copy(XPS). The changes of binding energy indicate the existence of distinct charge transfer phenomena in ligand molecules after the ligands forming th e mononuclear complexes. The charge transfers from oxygen atoms to nitrogen atoms via pi-bond in the ligand molecule when Cu(II) ion is coordinated an d from nitrogen atoms to oxygen atoms when Eu(III) ion is coordinated. Afte r the Cu(II) ion and Eu(III) ion are both coodinated, the charge transfer p henomenon 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.