title: Gas-phase ion/molecule reactions between dimethoxyphosphonium ions and aromatic hydrocarbons.
abstract: Ion/molecule reactions between O=P(OCH(3))(2)(+) phosphonium ions and six aromatic hydrocarbons (benzene, toluene, 1,2,4-trimethylbenzene, naphthalene, acenaphthylene and fluorene) were performed in a quadrupole ion trap mass spectrometer. The O=P(OCH(3))(2)(+) phosphonium ions, formed by electron impact from neutral trimethyl phosphite, were found to react with aromatic hydrocarbons (ArHs) to give (i) an adduct [ArH, O=P(OCH(3))(2)](+) and (ii) for ArHs which have an ionization energy below or equal to 8.14 eV, a radical cation ArH(+ *) by charge transfer reaction. Collision-induced dissociation experiments, which produce fragment ions other than the O=P(OCH(3))(2)(+) ions, indicate that the adduct ions are covalent species. Isotope-labeled ArHs were used to elucidate fragmentation mechanisms. The charge transfer reactions were investigated using density functional theory at the B3LYP/6-311 + G(3df,2p)//B3LYP/6-31G(d,p) level of theory. The potential energy surface obtained from B3LYP/6-31G(d,p) calculations for the reaction between O=P(OCH(3))(2)(+) and benzene is described.
authors.affiliation: Laboratoire Analyse et Environnement, Université d'Evry Val d'Essonne, CNRS UMR 8587, Bd François Mitterrand, 91025 Evry Cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Leclerc
authors.forename: William
authors.initials: W
authors.lastname: Buchmann
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Taphanel
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Morizur