Benzyl anion transfer in the fragmentation of N-(phenylsulfonyl)-benzeneacetamides: a gas-phase intramolecular SNAr reaction

2015 ◽  
Vol 13 (40) ◽  
pp. 10205-10211 ◽  
Author(s):  
Shanshan Shen ◽  
Yunfeng Chai ◽  
Yaqin Liu ◽  
Chang Li ◽  
Yuanjiang Pan
Keyword(s):  
Gas Phase ◽  
Snar Reaction ◽  
Anion Transfer

This work is the first example reporting the gas-phase benzyl anion transfer to conduct the intramolecular SNAr reactions.

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 computational study of the SNAr reaction of 2-ethoxy-3,5-dinitropyridine and 2-methoxy-3,5-dinitropyridine with piperidine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Oluwakemi A. Oloba-Whenu ◽  
Idris O. Junaid ◽  
Chukwuemeka Isanbor
Keyword(s):  
Hydrogen Bonding ◽  
Gas Phase ◽  
Density Functional ◽  
Computational Study ◽  
Density Functional Theory Method ◽  
Basis Set ◽  
Slow Step ◽  
Functional Theory ◽  
Snar Reaction ◽  
Hybrid Density Functional

AbstractA computational study of the chemical kinetics and thermodynamics study of the SNAr between 3,5-dinitroethoxypyridine 1a and 3,5-dinitromethoxypyridine 1b with piperidine 2 in the gas phase is reported using hybrid density functional theory method B3PW91 and 6–31G(d,p) basis set. The reaction was modeled via both the catalyzed and base-catalyzed pathways which proceeded with the initial attack of the nucleophile 2 on the substrates 1 to yield the Meisenheimer complex intermediate that is stabilized with hydrogen bonding. Calculations show that the reaction goes via the formation and decomposition of a Meisenheimer complex, which was observed to be stabilized by hydrogen bonding. Along the uncatalyzed pathway, the decomposition of the Meisenheimer complex was the slow step and requires about 28 kcal/mol. This barrier was reduced to about 14.8 kcal/mol with the intervention of the base catalyst, thus making the formation of the Meisenheimer complex rate determining. All reactions were calculated to be exothermic, about −6.5 kcal/mol and −0.6 kcal/mol, respectively, for the reaction of 1a and 1b with 2.

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.

Dynamics of a gas-phase SNAr reaction: non-concerted mechanism despite the Meisenheimer complex being a transition state

2020 ◽  
Vol 22 (45) ◽  
pp. 26562-26567
Author(s):  
Nishant Sharma ◽  
Rupayan Biswas ◽  
Upakarasamy Lourderaj
Keyword(s):  
Transition State ◽  
Gas Phase ◽  
Substitution Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Concerted Mechanism ◽  
Snar Reaction

Multi-step roaming pathway in the nucleophilic aromatic substitution reaction involving a Meisenheimer transition state.

Residual Gas Reactions in the Electron Microscope: I. Qualitative Observations on the Water Gas Reaction

1968 ◽  
Vol 26 ◽  
pp. 292-293
Author(s):  
Richard E. Hartman ◽  
Roberta S. Hartman ◽  
Peter L. Ramos
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Gas Phase ◽  
Absolute Temperature ◽  
Residual Gas ◽  
Gas Reactions ◽  
Image Position ◽  
The Right ◽  
Water Gas ◽  
Thinning Rate

The action of water and the electron beam on organic specimens in the electron microscope results in the removal of oxidizable material (primarily hydrogen and carbon) by reactions similar to the water gas reaction .which has the form:The energy required to force the reaction to the right is supplied by the interaction of the electron beam with the specimen.The mass of water striking the specimen is given by:where u = gH2O/cm2 sec, PH2O = partial pressure of water in Torr, & T = absolute temperature of the gas phase. If it is assumed that mass is removed from the specimen by a reaction approximated by (1) and that the specimen is uniformly thinned by the reaction, then the thinning rate in A/ min iswhere x = thickness of the specimen in A, t = time in minutes, & E = efficiency (the fraction of the water striking the specimen which reacts with it).

Integration of Core-Edge Spectroscopy Methods for the Study of Polymers

1996 ◽  
Vol 54 ◽  
pp. 154-155
Author(s):  
E. G. Rightor
Keyword(s):  
Excited State ◽  
Polymer Blends ◽  
Gas Phase ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Electronic States ◽  
Core Electron ◽  
Bulk Solids ◽  
Development Application

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.

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