Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase

1998 ◽  
Vol 63 (9) ◽  
pp. 1498-1512 ◽  
Author(s):  
Ulf Mazurek ◽  
Detlef Schröder ◽  
Helmut Schwarz
Keyword(s):  
Gas Phase ◽  
Bond Activation ◽  
Branching Ratio ◽  
Radical Cations ◽  
Reaction Pathways ◽  
Ion Cyclotron Resonance ◽  
Ion Transfer ◽  
Consistent Picture ◽  
Anion Transfer ◽  
Chain Lengths

Gaseous chromium fluoride monocations CrFn+ (n = 1-4) can be prepared by sequential fluorine-atom transfer from nitrogen trifluoride, NF3, to chromium cation. In addition, formal F- anion transfer to CrFn+ (n = 2-4) to yield the corresponding neutral chromium fluorides CrFn+1 is observed. In conjunction with a re-evaluation of previous data, the present results provide a consistent picture of the thermochemistry of neutral and cationic chromium fluorides. The reactivity of the CrFn+ ions towards alkanes is investigated in a Fourier-transform ion cyclotron resonance mass spectrometer. While "bare" Cr+ does not react with alkanes, the chromium fluoride cations CrFn+ do; CrF3+ and CrF4+ are even capable of activating methane. With both increasing oxidation state of chromium and increasing chain lengths of the alkane, the branching ratio of the possible reaction pathways shifts from homolytic C-H and C-C bond activation to hydride- and methanide-ion transfer to yield carbocations, and finally electron transfer generating hydrocarbon radical cations.

A gas phase study of the regioselective BH4− reduction of some 2-substituted maleic anhydrides

1988 ◽  
Vol 66 (10) ◽  
pp. 2587-2594 ◽  
Author(s):  
Hans van der Wel ◽  
Nico M. M. Nibbering ◽  
Margaret M. Kayser
Keyword(s):  
Carbon Atom ◽  
Gas Phase ◽  
Ion Cyclotron Resonance ◽  
Ion Transfer ◽  
Hydride Ion ◽  
Ion Molecule Reactions ◽  
Phase Study ◽  
Olefinic Double Bond ◽  
Gas Phase Ion ◽  
Hydride Ion Transfer

Gas phase ion/molecule reactions in a Fourier transform ion cyclotron resonance mass spectrometer have been carried out for reductions of isotopically labelled citraconic (methylmaleic), phenylmaleic, and ethoxymaleic anhydrides by BH4−. In citraconic anhydride the carbonyl group neighbouring the methyl substituent is reduced preferentially in agreement with the ab initio calculations, which show the higher LUMO coefficients at this site. Hydride ion transfer to the olefinic double bond occurs as well; however, in that case no preference for either of the carbon atoms is observed. In phenylmaleic anhydride strong indications are found for a theoretically unexpected hydride ion transfer to the phenyl ring. For ethoxymaleic anhydride experimental evidence is presented showing hydride ion transfer to the carbon atom carrying the ethoxy group, which is in agreement with the "best overlap" consideration predicting that this carbon atom bears the highest LUMO coefficient.Most of the hydride transfers from BH4− to the molecules studied seem, therefore, to take place under orbital control rather than under control of long-range ion-induced dipole interactions between reactants.

An ion cyclotron resonance study of competitive solvation of gas phase anions

1979 ◽  
Vol 57 (5) ◽  
pp. 473-477 ◽  
Author(s):  
R. L. Clair ◽  
T. B. McMahon
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Carboxylic Acids ◽  
Propionic Acid ◽  
Cyclotron Resonance ◽  
Binding Energies ◽  
Ion Cyclotron Resonance ◽  
Fluoride Ions ◽  
Carboxylate Anions ◽  
Anion Transfer

Reactions of trifluoromethoxide ion, CF3O−, with carboxylic acids have been examined. Facile fluoride transfer is observed to occur to the acids and a subsequent fluoride transfer equilibrium established in mixtures of carboxylic acids. From the equilibrium constant obtained for fluoride transfer acetic acid and propionic acid are found to have near identical fluoride binding energies. Further reaction between the acid solvated fluoride ions and the carboxylic acids is observed to occur resulting in HF displacement and formation of bicarboxylate anions. In mixtures of acetic and propionic acids acetate and propionate anion transfer equilibria are again established. An analysis of the energetics for these processes reveals that propionic acid binds the carboxylate anions more strongly than acetic acid by 0.1 to 0.2 kcal/mol.

Reactivity Trends in the Gas Phase Addition of Acetylene to N-protonated Aryl Radical Cations

2020 ◽  
Author(s):  
Oisin Shiels ◽  
P. D. Kelly ◽  
Cameron C. Bright ◽  
Berwyck L. J. Poad ◽  
Stephen Blanksby ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ion Trap ◽  
Radical Cations ◽  
Rate Coefficients ◽  
Similar Process ◽  
Ion Molecule Reactions ◽  
Aromatic Radicals ◽  
Polycyclic Aromatic ◽  
Gas Phase Ion ◽  
Type Radical

<div> <div> <div> <p>A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N- containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl) and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios and reaction efficiencies are reported. </p> </div> </div> </div>

Dissecting transmetalation reactions at the molecular level: C–B versus F–B bond activation in phenyltrifluoroborate silver complexes

2021 ◽  
Vol 50 (4) ◽  
pp. 1496-1506
Author(s):  
Fiona Bathie ◽  
Adam W. E. Stewart ◽  
Allan J. Canty ◽  
Richard A. J. O'Hair
Keyword(s):  
Gas Phase ◽  
Bond Activation ◽  
Molecular Level ◽  
Silver Complexes ◽  
Fundamental Model ◽  
Model Reactions

Gas-phase experiments and computation provide fundamental model reactions for aryl and fluoride transfer between silver and boron centres.

ChemInform Abstract: Unstrained C-C Bond Activation and Directed Fluorination Through Photocatalytically-Generated Radical Cations.

ChemInform ◽  
2015 ◽  
Vol 46 (52) ◽  
pp. no-no
Author(s):  
Cody Ross Pitts ◽  
Michelle Sheanne Bloom ◽  
Desta Doro Bume ◽  
Qinze Arthur Zhang ◽  
Thomas Lectka
Keyword(s):  
Bond Activation ◽  
Radical Cations

Thermal NH Bond Activation on Anionic and Cationic Platinum Clusters: Non-Predetermined Reaction Pathways Indicate Transitions to a Bulk Surface Reactivity

2009 ◽  
Vol 15 (34) ◽  
pp. 8465-8474 ◽  
Author(s):  
Milan Ončák ◽  
Yali Cao ◽  
Robert F. Höckendorf ◽  
Martin K. Beyer ◽  
Rudolf Zahradník ◽  
...  
Keyword(s):  
Bond Activation ◽  
Surface Reactivity ◽  
Reaction Pathways ◽  
Bulk Surface ◽  
Platinum Clusters
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