scholarly journals Bimolecular production of proton bound dimers in the gas phase. A low pressure ion cyclotron resonance technique for examination of solvent exchange equilibria and determination of single molecule solvation energetics

1982 ◽  
Vol 60 (4) ◽  
pp. 542-544 ◽  
Author(s):  
J. W. Larson ◽  
R. L. Clair ◽  
T. B. McMahon
Keyword(s):  
Gas Phase ◽  
Single Molecule ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Solvent Exchange ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Gas Phase Ion ◽  
Low Pressures

A scheme is presented whereby sequences of fast bimolecular gas phase ion molecule reactions in mixtures containing (CHF2)2O may be used to generate proton bound dimer species at low pressures in an ion cyclotron resonance spectrometer. Using competitive solvent switching reactions it is demonstrated that solvent exchange equilibria may be readily established and from the thermochemical data derived from such equilibria accurate relative single molecule solvation energetics obtained.

Thermodynamic control in the reactions of gas phase anions. An abinitio and ion cyclotron resonance study of the reactions of anions with diborane

1985 ◽  
Vol 63 (2) ◽  
pp. 281-287 ◽  
Author(s):  
O. Elsenstein ◽  
M. Kayser ◽  
M. Roy ◽  
T. B. McMahon
Keyword(s):  
Gas Phase ◽  
Cyclotron Resonance ◽  
Reaction Pathway ◽  
Basis Set ◽  
Resonance Spectroscopy ◽  
Ion Cyclotron Resonance ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Reaction Channels ◽  
Gas Phase Ion

The gas phase ion molecule reactions of a number of anions, X−, with diborane, B2H6 have been investigated using ion cyclotron resonance spectroscopy. Two distinct reaction channels are observed in addition to simple proton transfer. The first of these is production of BH4− and BH2X while the second is formation of BH3X− and BH3. In order to determine the importance of thermodynamic factors in the course of reaction abinitio calculations have been carried out on the species involved to obtain the relative stabilities of the two possible pairs of products. The 4-31 +G basis set incorporating additional flat s and p functions has been used since this basis set has been demonstrated to give the most accurate description of anions to date. The results obtained indicate that the thermochemical factors are instrumental in determining the reaction pathway.

Bimolecular production of gas phase ionic hydrates by ion cyclotron resonance spectroscopy

1980 ◽  
Vol 58 (8) ◽  
pp. 863-865 ◽  
Author(s):  
R. L. Clair ◽  
T. B. McMahon
Keyword(s):  
Gas Phase ◽  
Cyclotron Resonance ◽  
Resonance Spectroscopy ◽  
Ion Cyclotron Resonance ◽  
Ion Chemistry ◽  
Ion Molecule Reactions ◽  
Hydronium Ion ◽  
Dominant Feature ◽  
Ion Cyclotron ◽  
Gas Phase Ion

The gas phase ion–molecule reactions of α,α,α′,α′ tetrafluorodimethyl ether both alone and in mixtures with water have been examined. The dominant feature of the ion chemistry of these mixtures is the sequential bimolecular production of the hydrated hydronium ion, H5O2+. Two independent mechanistic pathways for production of H5O2+ are outlined arising from reaction of H3O+ with (CF2H)2O and from CF2H—O=CHF+ with H2O. Implications for examination of solvent switching equilibria are discussed.

Gas phase acidic solvolysis reactions of acyl halides by ion cyclotron resonance spectroscopy

1978 ◽  
Vol 56 (5) ◽  
pp. 670-679 ◽  
Author(s):  
T. B. McMahon
Keyword(s):  
Gas Phase ◽  
Cyclotron Resonance ◽  
Resonance Spectroscopy ◽  
Ion Cyclotron Resonance ◽  
Elimination Reaction ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Process Observation ◽  
Gas Phase Ion ◽  
Acyl Halides

A number of gas phase ion molecule reactions of protonated species with acyl halides have been examined by ion cyclotron resonance spectroscopy. A number of these reactions are found to involve an addition–elimination reaction having the character of an acidic solvolysis process. Observation of the occurrence or non-occurrence of such reactions and a consideration of appropriate thermochemical data allow a set of criteria to be formulated governing the feasibility of observing the acidic solvolysis reaction. In addition a number of mechanistic inferences are made concerning intermediates involved in the various reactions.

Bimolecular reactions of nucleophiles in the gas phase. The reaction of the methoxide anion with ketones. An ion cyclotron resonance study

1980 ◽  
Vol 33 (10) ◽  
pp. 2271 ◽  
Author(s):  
G Klass ◽  
JH Bowie
Keyword(s):  
Gas Phase ◽  
Cyclotron Resonance ◽  
Ion Cyclotron Resonance ◽  
Bimolecular Reactions ◽  
Methyl Nitrite ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Methoxide Anion

The methoxide anion (produced from methyl nitrite) reacts with neutral ketones (M) to form non-decomposing(M-H+)- ions. The (M-H+)- ions are ambident species and they undergo a number of ion-molecule reactions, including (i) characteristic reactions through the carbanion centre with methyl nitrite, and (ii) for acetone, the formation of an [M +(M- H+)]- ion. In several cases peaks due to collision-stabilized (M+MeO-) ions are observed (e.g. MeO-/acetone), but they are not detected for the majority of cases studied.

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