Benchmark calculations of proton affinity and gas‐phase basicity using multilevel ( G4 and G3B3 ), B3LYP and MP2 computational methods of para‐substituted benzaldehyde compounds

2021 ◽  
Author(s):  
Zaki S. Safi ◽  
Nuha Wazzan
Keyword(s):  
Gas Phase ◽  
Proton Affinity ◽  
Computational Methods

Predicting ion rearrangement reactions — The energetics of the internal SN2 reaction in gas-phase proton-bound molecular pairs

2005 ◽  
Vol 83 (11) ◽  
pp. 1864-1870 ◽  
Author(s):  
Julie AD Grabowy ◽  
Paul M Mayer
Keyword(s):  
Key Words ◽  
Gas Phase ◽  
Proton Affinity ◽  
Intermediate Complex ◽  
Isomerization Reaction ◽  
Base System ◽  
Alkyl Groups ◽  
Rearrangement Reaction ◽  
Metastable Ions ◽  
The Difference

A common rearrangement reaction for gas-phase proton-bound molecular pairs corresponds to an internal SN2 reaction that results in the loss of a small neutral molecule. For pairs (RCN)(ROH)H+, the energies of the two transition states (TSa and TSb) and the intermediate complex (IC) in the isomerization reaction (relative to the proton-bound pair, in kJ mol–1) can be estimated using the following relationships: E(TSa) = 87 – 9(n) – 0.33(ΔPA), E(IC) = 83 – 9(n) – 0.33(ΔPA), and E(TSb) = 107 – 9(n) – 0.10(ΔPA), where 87, 83, and 107 kJ mol–1 are the values for (CH3CN)(CH3OH)H+. Here, n is the number of stablizing alkyl groups on the central SN2 carbon and ΔPA is the difference between the proton affinity of the migrating moiety and that for the base system (in this case, CH3CN). For the analogous pairs (ROH)(R′OH)H+, only the first value in each expression is different (98, 94, and 121 kJ mol–1, respectively, calculated for (CH3OH)2H+).Key words: proton-bound molecular pairs, isomerization, internal SN2 reaction, energetics, metastable ions.

Theoretical Investigation of the Proton Affinity and Gas-Phase Basicity of Neutral x,y-Dihydroxybenzoic Acid and its Derivatives

2006 ◽  
Vol 12 (6) ◽  
pp. 385-396 ◽  
Author(s):  
Brandon L. Rebber ◽  
J. Anthony Halfacre ◽  
Kyle A. Beran ◽  
Nicholas R. Beller ◽  
Mario Gomez ◽  
...  
Keyword(s):  
Gas Phase ◽  
Proton Affinity ◽  
Theoretical Investigation ◽  
Dihydroxybenzoic Acid
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