Neutral Metal Atoms Acting as a Leaving Group in Gas-Phase SN2 Reactions: M(CH3)++ NH3→ CH3NH3++ M (M = Zn, Cd, Hg)

2012 ◽  
Vol 31 (10) ◽  
pp. 3816-3824 ◽  
Author(s):  
Robert Kretschmer ◽  
Maria Schlangen ◽  
Martin Kaupp ◽  
Helmut Schwarz
Keyword(s):  
Gas Phase ◽  
Sn2 Reactions ◽  
Metal Atoms ◽  
Leaving Group ◽  
Neutral Metal

Effects of Substituent and Leaving Group on the Gas-Phase SN2 Reactions of Phenoxides with Halomethanes: A DFT Investigation

2009 ◽  
Vol 113 (38) ◽  
pp. 10359-10366 ◽  
Author(s):  
Qiang-gen Li ◽  
Ying Xue
Keyword(s):  
Gas Phase ◽  
Sn2 Reactions ◽  
Leaving Group

Effect of the Leaving Group on the Rates of SN2 and SN2' Reactions in Allylic Systems

1960 ◽  
Vol 82 (11) ◽  
pp. 2881-2888 ◽  
Author(s):  
F. G. Bordwell ◽  
Phillip E. Sokol ◽  
James D. Spainhour
Keyword(s):  
Sn2 Reactions ◽  
Leaving Group

Mechanisms of aromatic nucleophilic substitution by the ambident thiocyanate ion

1973 ◽  
Vol 26 (2) ◽  
pp. 273 ◽  
Author(s):  
DE Giles ◽  
AJ Parker
Keyword(s):  
Nucleophilic Substitution ◽  
Transition States ◽  
Reactivity Ratio ◽  
Substitution Reactions ◽  
Aromatic Nucleophilic Substitution ◽  
Thiocyanate Ion ◽  
Sn2 Reactions ◽  
Leaving Group ◽  
Electrophilic Reactivity ◽  
Saturated Carbon Atom

Sulphur/nitrogen reactivity ratios in a series of aromatic nucleophilic substitution reactions of ambident thiocyanate ion have been determined. There are profound differences from the pattern found in SN2 reactions at a saturated carbon atom. Abnormal transition states, involving interactions between entering and leaving group, are likely in the bond-breaking step of the intermediate complex in reactions of thiocyanate ion with 1-fluoro-2,4-dinitrobenzene and with 2,4- dinitrophenyl 4-toluenesulphonate. The nitro-substituted aryl thiocyanates are shown to be tri-functional electrophiles, with reactive centres at aromatic carbon, at cyanide carbon, and at sulphur. Aryl 4-toluenesulphonates are bifunctional electrophiles with reactive centres at aryl carbon and sulphonyl sulphur. The site of attack by nucleophiles depends on the nature of the nucleophile. The sulphur/nitrogen reactivity ratio of ambident SCN-, and the electrophilic reactivity of tri- and bi-functional substrates, are in most instances consistent with the Hard and Soft Acids and Bases principle. Exceptions to the principle in some instances reveal differences between the SNAr and SN2 mechanisms, and in others indicate abnormal transition states.

scholarly journals Benchmark ab Initio Energy Profiles for the Gas-Phase SN2 Reactions Y-+ CH3X → CH3Y + X-(X,Y = F,Cl,Br). Validation of Hybrid DFT Methods

2001 ◽  
Vol 105 (5) ◽  
pp. 895-904 ◽  
Author(s):  
Srinivasan Parthiban ◽  
Glênisson de Oliveira ◽  
Jan M. L. Martin
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Dft Methods ◽  
Sn2 Reactions ◽  
Energy Profiles

scholarly journals The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bingkun Yu ◽  
Xianghui Xue ◽  
Chengling Kuo ◽  
Gaopeng Lu ◽  
Christopher J. Scott ◽  
...  
Keyword(s):  
Lower Ionosphere ◽  
Atmospheric Tides ◽  
Metallic Ions ◽  
Number Density ◽  
Mesopause Region ◽  
Lidar Observation ◽  
Metal Atoms ◽  
Chemical Coupling ◽  
Coupling Processes ◽  
Neutral Metal

AbstractWe present a multi-instrument experiment to study the effects of tropospheric thunderstorms on the mesopause region and the lower ionosphere. Sodium (Na) lidar and ionospheric observations by two digital ionospheric sounders are used to study the variation in the neutral metal atoms and metallic ions above thunderstorms. An enhanced ionospheric sporadic E layer with a downward tidal phase is observed followed by a subsequent intensification of neutral Na number density with an increase of 600 cm−3 in the mesosphere. In addition, the Na neutral chemistry and ion-molecule chemistry are considered in a Na chemistry model to simulate the dynamical and chemical coupling processes in the mesosphere and ionosphere above thunderstorms. The enhanced Na layer in the simulation obtained by using the ionospheric observation as input is in agreement with the Na lidar observation. We find that the intensification of metallic layered phenomena above thunderstorms is associated with the atmospheric tides, as a result of the troposphere-mesosphere-ionosphere coupling.

Photoinitiation of Gas-Phase SN2 Reactions through the Evans−Polanyi Excited State Surface

1997 ◽  
Vol 119 (21) ◽  
pp. 5067-5068 ◽  
Author(s):  
Caroline E. H. Dessent ◽  
Mark A. Johnson
Keyword(s):  
Excited State ◽  
Gas Phase ◽  
Sn2 Reactions

Gas-phase SN2 reactions at silicon and carbon centers. An experimental appraisal of theory

1976 ◽  
Vol 98 (4) ◽  
pp. 894-899 ◽  
Author(s):  
J. D. Payzant ◽  
K. Tanaka ◽  
L. D. Betowski ◽  
D. K. Bohme
Keyword(s):  
Gas Phase ◽  
Carbon Centers ◽  
Sn2 Reactions
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