V. I. Vovna

The photoelectron spectroscopy and electronic structure of metal β-diketonates and their analogs

Abstract He(I) photoelectron spectra of transition and non-transition metal bis- and tris-β-diketonate complexes were studied. Spectra have been interpreted based on the study of regularities in spectra of compound rows and results of quantum chemical calculations of ground and ionized states by X α -DV and ab initio methods. In group III d-metal complexes, the bond covalency changes in the sequenceYL 3 3 3 , whereas for complexes of final elements in the transition row, the bond covalency is directly proportional to the period row. Ionization energy changes for O to NR group substitution, γ-H to Cl and CH 3 group, β-CH 3 groups to H, C(CH 3 ) and C 6 H 5 , are discussed. It was shown that for high-spin complexes, despite the closeness of the final state energies, ψ-function symmetry prohibits the interaction between states caused by d- and L-electrons removal.

The electron relaxation and UP spectra of metal coordination compounds

Abstract The electronic structure of 3d-metals bis and tris-β-diketonates was studied by methods of UP spectroscopy and quantum chemistry in ab initio, Xα-DV and INDO approximations. According to PE data, the covalent interaction metal-legand is realized, on the whole, by n-electrons, and IE 1 in all compounds caused by d-electrons. The Xα-DV calculations give a good agreement with experimental picture of interaction of metal AOs and ligand orbitals. Ab initio calculations showed the main role of high σ-orbitals in covalent interaction. All quantum chemical methods overstate multiplet splitting of ligand levels caused by overestimation of a delocalization factor of d-electrons.

EXPERIMENTAL AND THEORETICAL INVESTIGATION OF ALUMINIUM, GALLIUM AND INDIUM TRIS-ACETYLACETONATES GROUND, EXCITED AND IONIZED STATES NATURE

Abstract The electronic structures of aluminium, gallium and indium tris-acetylacetonates were investigated by methods of photoelectron, absorption electronic spectroscopy and quantum chemistry. The experimental and theoretical ionization energies and electron transition energies were determined; the nature of correspondent ground, ionized and excited states was studied. The main regularities of electronic spectra changes during central atom substitution were established. The communication between geometry and some energetical characteristics of present compounds in ground, excited and ionized states were studied.

Photoelectron spectra and electronic structure of some zinc thio-β-diketonates

Abstract For the first time, the photoelectron spectra were obtained for a variety of complexes of Zn(II) with thiodibenzoylmethane (Sdbm), dithioacetylacetone (S2acac), trifluorothioacetylactone (tFSac), napthylthioacetone (ntSac), trifluorothiotrimethoxybenzoylacetone (tFtMeOSbzac), trifluorothioethoxybenzoylacetone (tFEtOSbzac), and ethoxythiobenzoylacetone (SbzacOEt). For interpretation of these spectra, we calculated the electronic structure of these and some other β-diketonates and thio-β-diketonates of Zn(II) with different functional groups in β-positions of the ligands. The joint analysis of the obtained experimental and theoretical data allowed us to establish for these compounds: (a) the major characteristics of electronic structure of compounds studied; (b) some correlations between electronic structure, photoelectron spectra, and the types of functional groups in β-positions of the ligands; and (c) experimental and theoretical ionization energies, and character of relevant spectral bands.

Electronic structure of Ni(II) acetylacetonate and its γ-substituted analogs

The ab initio Hartree–Fock method with the DZA basis in single- and multideterminant approximations was used to study the electronic structure of nickel bis(acetylacetonate) and its γ-substituted analogs (X = Cl and CH3). The character and sequence of canonical molecular orbitals were determined; the influence of γ-substituents and the role of the correlation and relaxation effects were elucidated.

Electronic structure of some bis-β-diketonates of zinc and their thio-analogs

Abstract For interpretation of photoelectron and absorption electronic spectra of a series of thio- and dithio-Zn(II)-β-diketonates, the electronic structures of zinc acetylacetonates (acac), benzoylacetonates (bza), dibenzoylmethanates (dbm) and their thio-analogs were calculated with the aid of the quantum chemical MNDO method with and without taking into account the configuration interaction. One-electron ionization energies, ground, excited and ionized state energies of the present compounds have been determined. The nature of these states, the regularities of their change during substitution of oxygen to sulphur, and CH 3 -groups to C 6 H 5 have been established.

THE ELECTRONIC STRUCTURE OF TRIFLUOROBENZOYLACETONATES OF AL(III), GA(III)AND IN(III)

Abstract In order to investigate the electronic effects of the substitution of trifluoro and phenyl groups on diketonates chelate rings we have measured the photoelectron and absorption electron spectra of the trifluorobenzoylacetonates of aluminum, galliurn and indium. The electronic structure of these compounds and the Al, Ga, In trifluoroacetylacetonates and their benzoylacetonates in the ground, excited and ionized states (PM3/CI method) was calculated. This was done using experimental and theoretical ionization energies, exciting energies along with the nature of corresponding ionized and excited states from which spectral interpretations are proposed. On the strength of obtained results we have established the main patterns of electronic structure and changes in the spectra of the studied β-diketonates depending on the functional groups and the central atom.