Electronic structure and photoelectron spectra of nickel(II)-beta-diketonate complexes

The photoelectron spectra of the nickel(II) complexes of acetylacetone, ace tylacetoimine, ethylenebis(acetylacetoimine) have been measured and quantum chemical calculations by X-alpha-DV method have been fulfilled. The spectr a were interpreted, the nature of occupied molecular orbitals was establish ed, and the effect of oxygen atoms substitution to -NR- groups was analyzed . From the average energies of even and odd group orbitals equality in the ligands structure (AA(-))(2) and predominant contribution of even MOs in co valent bonding in Ni(AA)(2), the values of the complex covalent stabilizati on have been calculated. The results of Ni(AA)(2)(+) calculations with vaca ncies at different MOs allowed the appreciation the relaxation values of co mplex MOs. The ionization energies were obtained in two ways: one based on full energy differences E(Ni(AA)(2)(+))-E(Ni(AA)(2)) and the other by the t ransition state method: IEi = - epsilon(i)(n = 1/2). (C) 1999 Elsevier Scie nce B.V. All rights reserved.