1,721,007 research outputs found
Gas Phase Ion Chemistry of BF3/HN3 Mixtures. The First Observation of [BFnHxHn-1]+ (n=1,2; x= 1,3)Ions
No full textGas-phase reactions of protonated chlorine, Cl2H+ , with H2 (D2 ) and CH4 . A mass spectrometric and theoretical study
No full textFrom vacuum to atmospheric pressure: A review of ambient ion soft landing
No full textThe capability to deposit intact highly pure ionic species makes ion soft landing an advantageous mass spectrometric method able to create molecular layers on solid surfaces. Recent advances in this technique gave the possibility to manipulate solvent-free ions in open-air conditions. The high ionic current produced by the new sources as well as the developments of accelerated systems dramatically increase the efficiency of the soft landing process, opening new opportunities for surface modification with self-organized polyatomic structures. This review reports the developments of the ambient ion soft landing, highlights its most recent applications and discusses future perspectives
GAS-PHASE CHEMISTRY OF DIPHOSPHATE ANIONS AS A TOOL TO INVESTIGATE THE INTRINSIC REQUIREMENTS OF PHOSPHATE ESTER ENZYMATIC REACTIONS: THE [M1M2HP2O7]- IONS
No full textExperimental studies on gaseous inorganic phosphate ions are practically nonexistent, yet they can prove helpful for a better understanding of the mechanisms of phosphate ester enzymatic processes. The present contribution extends our previous investigations on the gas-phase ion chemistry of diphosphate species to the [M1M2HP2O7]- ions where M1 and M2 are the same or different and correspond to the Li, Na, K, Cs, and Rb cations.
The diphosphate ions are formed by electrospray ionization of 10-4M solutions of Na5P3O10 in CH3CN/H2O (1/1) and MOH bases or M salts as a source of M+ cations. The joint application of mass spectrometric techniques and quantum-mechanical calculations makes it possible to characterize the gaseous [M1M2HP2O7]- ions as a mixed ionic population formed by two isomeric species: linear diphosphate anion coordinated to two M+ cations (group I) and[PO3···MH2PO4]- clusters II and the [PO3···M1M2···HPO4]- clusters (group II). The relative gas-phase stabilities and activation barriers for the isomerization I-> II, which depend on the nature of the M+ cations, highlight the electronic
susceptibility of P-O-P bond breaking in the active site of enzymes. The previously unexplored gas-phase reactivity of [M1M2HP2O7]- ions towards alcohols of different acidity was investigated by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). The reaction proceeds by addition of the alcohol molecule followed by elimination of a water molecule
Sulfur hexafluoride corona discharge decomposition: gas-phase ion chemistry of SOFx+ (x =1-3) ions
No full textSulfur hexafluoride corona discharge decomposition: gas-phase ion chemistry of SOF x + (x = 1-3) ions
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The Mechanism of 2-Furaldehyde Formation from D-Xylose Dehydration in the Gas Phase. A Tandem Mass Spectrometric Study
Full text linkThe mechanism of reactions occurring in solution can be investigated also in the gas phase by suited mass spectrometric techniques, which allow to highlight fundamental mechanistic features independent of the influence of the medium and to clarifying controversial hypotheses proposed in solution studies. In this work, we report a gas-phase study performed by electrospray triple stage quadrupole mass spectrometry (ESI-TSQ/MS) on the dehydration of d-xylose, leading mainly to the formation of 2-furaldehyde (2-FA). It is generally known in carbohydrate chemistry that the thermal acid catalyzed dehydration of pentoses leads to the formation of 2-FA, but several aspects on the solution-phase mechanism are controversial. Here, gaseous reactant ions corresponding to protonated xylose molecules obtained from ESI of a solution containing d-xylose and ammonium acetate as protonating reagent were allowed to undergo collisionally activated decomposition (CAD) into the triple stage quadrupole analyzer. The product ion mass spectra of protonated xylose are characterized by the presence of ionic intermediates arising from xylose dehydration, which were structurally characterized by their fragmentation patterns. As expected, the xylose triple dehydration leads to the formation of the ion at m/z 97, corresponding to protonated 2-FA. On the basis of mass spectrometric evidences, we demonstrated that in the gas phase, the formation of 2-FA involves protonation at the OH group bound to the C1 atom of the sugar, the first ionic intermediate being characterized by a cyclic structure. Finally, energy resolved product ion mass spectra allowed to obtain information on the energetic features of the d-xylose→2-FA conversion. © 2013 American Society for Mass Spectrometry
The Metal Alkali Coordination Effect on the Diphosphate Gas Phase Ion Chemistry. The MH2P2O7- Ions
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