title: Energetics of the ligated vanadium dications VO2+, VOH2+, and [V,O,H2]2+.
abstract: Charge-stripping mass spectrometry and electronic structure calculations are combined to examine the energetics of the vanadium-containing dications VO2+, VOH2+, [HVOH]2+, and [V(OH2)]2+. Energy-resolved measurements, in conjunction with quantum-mechanical calculations, led to ionization energies (IE) of (VO+) = 16.6 +/- 0.3 eV and IE(VOH+) = 16.0 +/- 0.4 eV. Born-Haber cycles reveal that VO2+ and VOH2+ are both thermochemically stable dications with respect to their charge-separation asymptotes. Depending on the mode of ion generation, the [V,O,H2]+ monocations are formed as variable mixtures of the structural isomers [HVOH]+ and [V(OH2)]+. The measured IE([V,O,H2]+) = 13.7 +/- 0.3 eV is between the theoretical predictions for these isomers, indicating that mixtures of both isomers are sampled in the experiments. According to the theoretical results, [V(OH2)]2+ is also a thermochemically stable dication, whereas [HVOH]2+ is suggested to be metastable.
authors.affiliation: Institut für Chemie Technische Universität Berlin Strasse des 17. Juni 135, 10623 Berlin, Germany. detlef.schroeder@www.chem.tu-berlin.de
authors.forename: Detlef
authors.initials: D
authors.lastname: Schröder
authors.forename: Marianne
authors.initials: M
authors.lastname: Engeser
authors.forename: Helmut
authors.initials: H
authors.lastname: Schwarz
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Harvey