title: Ion chemistry of OV(OCH3)3 in the gas phase: molecular cations and anions and their primary fragmentations.
abstract: Trimethyl vanadate(V), OV(OCH(3))(3) (1), is examined by various mass spectrometric means. Photoionization experiments yield an ionization energy of IE(OV(OCH(3))(3)) = 9.54 +/- 0.05 eV for the neutral molecule. The primary fragmentation of the molecular cation 1(+), i.e., loss of neutral formaldehyde, can occur via two independent routes of hydrogen migrations to afford the formal V(IV) compounds HOV(OCH(3))(2)(+) and OV(OCH(3))(CH(3)OH)(+), respectively. These two pathways are associated with low-lying activation barriers of almost identical height. At elevated energies, direct V-O bond cleavage of 1(+) allows for expulsion of a methoxy radical concomitant with the generation of the cationic fragment OV(OCH(3))(2)(+), a formal V(V) compound. Trimethyl vanadate can also form a molecular anion, 1(-), whose most abundant dissociation channel involves loss of a methyl radical, thereby leading to the formal V(V) compound OV(OCH(3))(2)O(-). Various mass spectrometric experiments and extensive theoretical studies provide detailed insight into the ion structures and the relative energetics of the primary dissociation reactions of the molecular cations and anions of 1.
authors.affiliation: Institut für Chemie der Technischen Universität Berlin, Strasse des 17 Juni 135, D-10623 Berlin, Germany.
authors.forename: Detlef
authors.initials: D
authors.lastname: Schröder
authors.forename: Jessica
authors.initials: J
authors.lastname: Loos
authors.forename: Marianne
authors.initials: M
authors.lastname: Engeser
authors.forename: Helmut
authors.initials: H
authors.lastname: Schwarz
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Jankowiak
authors.forename: Robert
authors.initials: R
authors.lastname: Berger
authors.forename: Roland
authors.initials: R
authors.lastname: Thissen
authors.forename: Odile
authors.initials: O
authors.lastname: Dutuit
authors.forename: Jens
authors.initials: J
authors.lastname: Döbler
authors.forename: Joachim
authors.initials: J
authors.lastname: Sauer