title: Mass spectrometric characterization of metal triflates and triflimides (Lewis superacid catalysts) by electrospray ionization and tandem mass spectrometry.
abstract: Trifluoromethylsulfonate (triflate) and bis(trifluoromethylsulfonyl)imide (triflimide) salts, well-known Lewis acid catalysts, present some difficulty in their characterization. By using nitromethane as the solvent, useful electrospray mass spectra in positive and negative ion mode were obtained for salts of metals in oxidation states +2 and +3. In positive mode, addition of a strong Lewis base (triphenylphosphine oxide, TPPO), capable of displacing a triflate (TfO(-)) or a triflimide (Tf(2)N(-)) anion, is necessary for obtaining useful spectra. Under these conditions of solvent and added ligand, the most abundant ions were [M(2+)(A(-))(TPPO)(2)](+) or [M(3+)(A(-))(2)(TPPO)(2)](+) with A(-) = TfO(-) or Tf(2)N(-). The MS/MS spectra of these diagnostic ions provide additional analytical information. The breakdown curves, in the form of % dissociated as a function of the ion activation energy, offer a mean for investigating the bonding in these ions.
authors.affiliation: Laboratoire de Chimie des Molécules Bioactives et des Arômes, Institut de Chimie de Nice (FR CNRS 3037/UMR CNRS 6001), Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Monfardini
authors.forename: Lionel
authors.initials: L
authors.lastname: Massi
authors.forename: Pascale
authors.initials: P
authors.lastname: Tremel
authors.forename: Agnès
authors.initials: A
authors.lastname: Hauville
authors.forename: Sandra
authors.initials: S
authors.lastname: Olivero
authors.forename: Elisabet
authors.initials: E
authors.lastname: Duñach
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Gal