title: Investigating the electronic structure and bonding in uranyl compounds by combining NEXAFS spectroscopy and quantum chemistry.
abstract: The nature of the reactivity of the "yl" oxygens has been a subject of constant interest for a long time in uranyl chemistry. Thus, the electron-donor ability of the equatorial ligands plays an important role in the nature of the uranyl U=O bond. In this paper, a combination of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and both ground-state and time-dependent density functional theory (DFT) calculations have been used to examine the effect of equatorial plane ligation on the U=O bonding in two uranyl complexes: [UO(2)(py)(3)I(2)] and [UO(2)(CN)(5)][NEt(4)](3). By coupling experimental data and theory, spectral features observed in the oxygen K-edge NEXAFS spectra have been assigned. Despite the inert character of the U=O bond, we observe that the electron-donating or withdrawing character of the equatorial ligands has a measurable effect on features in the NEXAFS spectra of these species and thereby on the unoccupied molecular orbitals of {UO(2)}(2+).
authors.affiliation: CEA, DEN, DRCP, 30207 Bagnols sur Cèze, France. clara.fillaux@cea.fr
authors.forename: Clara
authors.initials: C
authors.lastname: Fillaux
authors.forename: Dominique
authors.initials: D
authors.lastname: Guillaumont
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Berthet
authors.forename: Roy
authors.initials: R
authors.lastname: Copping
authors.forename: David K
authors.initials: DK
authors.lastname: Shuh
authors.forename: Tolek
authors.initials: T
authors.lastname: Tyliszczak
authors.forename: Christophe
authors.initials: C
authors.lastname: Den Auwer