title: Structures of trimetallic molybdenum and tungsten suboxide cluster anions.
abstract: Anion photoelectron spectra of Mo(3)O(y)(-) and W(3)O(y)(-) (y = 3-6) are reported and analyzed using density functional theory results in an attempt to determine whether electronic and structural trends in the less oxidized clusters (y = 3, 4) could elucidate the disparate chemical properties of the M(3)O(y)(-) (M = Mo, W, y = 5, 6) species. In general, cyclic structures are calculated to be more stable by at least 1 eV than extended structures, and the lowest energy structures calculated for the most reduced species favor M = O terminal bonds. While the numerous low-energy structures found for Mo(3)O(y)(-)/Mo(3)O(y) and W(3)O(y)(-)/W(3)O(y) were, in general, similar, various structures of W(3)O(y)(-)/W(3)O(y) were found to be energetically closer lying than analogous structures of Mo(3)O(y)(-)/Mo(3)O(y). Additionally, the Mo-O-Mo bridge bond was found to be a more stabilizing structural motif than the W-O-W bridge bond, with the oxygen center in the former having the highest negative charge. Based on this, the observation of trapped intermediates in reactions between Mo(3)O(y)(-) and water or CO(2) that are not observed in analogous W(3)O(y)(-) reactivity studies may be partially attributed to the role of bridge bond fluxionality.
authors.affiliation: Indiana University, Department of Chemistry, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Rothgeb
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Mann
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Waller
authors.forename: Caroline Chick
authors.initials: CC
authors.lastname: Jarrold