1,721,081 research outputs found
Gas-phase proton affinity of nitric acid and its esters. A mass spectrometric and ab initio study on the existence and the relative stability of two isomers of protonated ethyl nitrate
No full textSulfur hexafluoride corona discharge decomposition: gas-phase ion chemistry of SOFn+ ions.
No full text– Edinburgo – Settembre 2003
“Gas-phase Fluorination of Acetylene: Formation, Structure and Reactvity of C2H2F+ Ions”
No full textStudi radiolitici di meccanismi di reazione: trasposizione di claisen acido catalizzata in fase gassosa
No full text
“Elemental Chlorine and Chlorine Fluoride: Theoretical and Experimental Proton Affinity and the Gas-Phase Chemistry of Cl2H+ and FClH+ Ions”.
No full textReactivity and Selectivity of the Methoxycarbonyl Cation in the Gas-Phase Electrofilic Aromatic Substitution
No full textProtonation induced ligand switching within NO2+ bound clusters.
No full textAn intracluster proton-promoted reaction leading to a ligand switching in mixed NOq2 complexes of nitric acid and its
derivatives is described. The proton affinity and the NOq2 binding energy are demonstrated to be the factors affecting the
process, the trend of which is shown to reflect the peculiar properties of nitric acid and its derivatives
Gas-phase NO+ affinities
No full textA scale of relative gas-phase NO+ binding energies (BEs) has been constructed by evaluation of NO+- transfer equilibria L1NO+ + L-2 reversible arrow L2NO+ + L-1 by Fourier-transform ion cyclotron resonance mass spectrometry and by application of the kinetic method, based on the metastable fragmentation of L-1(NO+)L-2 nitryl-ion bound dimers. The relative scale, anchored to the NO+ affinity of water, for 52 ligands, including alkyl halides, alkyl nitrates, alcohols, nitroalkanes, nitriles, aldehydes, ketones, and aromatic and heterocyclic compounds, led to an absolute NO+ affinity scale. The results are compared with those of an earlier study, and the apparent discrepancies are traced to a different choice of the absolute BE value used as the reference standard. The NO+ BEs fit a satisfactorily linear correlation when plotted versus the corresponding proton affinities (PAs). The NO+ BEs, while much lower than the PAs, are nevertheless higher than the corresponding BEs of the strictly related NO2+ cation, a result consistent with the experimental and theoretical results currently available on the structure and the stability of NO+ and NO2+ complexes. The NO+ BE vs. PA correlation allows one to estimate within 1-2 kcal . mol(-1) the NO+ BE of the molecules included in the comprehensive PA compilations currently available. For example, the correlation gives the following NO+ affinities of the DNA bases, in kcal . mol(-1) (1 kcal = 4.18 kJ): adenine, 40.3; cytosine, 40.4; guanine, 40.1; and thymine, 34.9. The experimental NO+ BE of thymine, the only one accessible to direct measurement, amounts to 35.6 +/- 2 kcal . mol(-1), which underlines the predictive value of the correlation. This study reports the second successful extension of the kinetic method to the evaluation of the absolute BEs of polyatomic cations, following our recent application to the strictly related NO2+ ion
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