title: Electronic Structure of Bis(2,4-pentanedionato-O,O')oxovanadium(IV). A Photoelectron Spectroscopy, Electronic Spectroscopy, and ab Initio Molecular Orbital Study.
abstract: The electronic structure of the title VO(acac)(2) complex has been investigated using effective core potential configuration interaction ab initio calculations, UV-photoelectron spectroscopy, and electronic spectroscopy. The metal-ligand bonding with the equatorial acac(-) ligands is dominated by sigma interactions involving the filled ligand orbitals and the empty orbitals of the d(1) vanadium(IV) ion. The oxovanadium interactions involve a larger metal-d participation thus resulting in a strong V-O bonding having partial triple-bond character. Additional three-orbital-four-electron stabilizing interactions involving the filled acac(-) MOs and the oxovanadium orbitals further reinforce both the axial and equatorial bonds. The unpaired metal-d electron is completely localized in the nonbonding d(x)()()2(-)(y)()()2 orbital. The low ionization energy of the photoelectron spectrum has been fully assigned on the basis of combined DeltaSCF and configuration interaction calculations. The same theoretical approach has, in addition, provided a good fitting of frequencies associated with "d-d" and charge transfer electronic transitions.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Catania, V.le A. Doria 8, 95125 Catania, Italy.
authors.forename: Santo
authors.initials: S
authors.lastname: Di Bella
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lanza
authors.forename: Antonino
authors.initials: A
authors.lastname: Gulino
authors.forename: Ignazio
authors.lastname: Fragalà