Computational investigations of the gas phase reactions between hydrogen chloride and protonated alkyl chlorides
| Autor: | Pervin Ünal Civcir |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
Substitution reaction Condensed Matter Physics Biochemistry Reaction coordinate chemistry.chemical_compound Elimination reaction chemistry Ab initio quantum chemistry methods Computational chemistry Nucleophilic substitution Physical chemistry SN2 reaction Physical and Theoretical Chemistry Hydrogen chloride Alkyl |
| Zdroj: | Journal of Molecular Structure: THEOCHEM. 848:128-138 |
| ISSN: | 0166-1280 |
| DOI: | 10.1016/j.theochem.2007.09.021 |
| Popis: | Ab initio calculations have been carried out for the gas phase identity nucleophilic substitution reactions between HCl and the protonated alkyl chlorides, MeClH+, EtClH+, PriClH+, and ButClH+. Geometries of stationary points along the reaction coordinate have been optimized at the B3LYP/6-31G(d), MP2/6-31G(d) and MP4/6-31G(d) level of theory. Additional single point energy calculations based on the MP2 optimized geometries are carried out at the full MP4 (SDTQ) level and improved energies have been calculated with the MP2/6-31++G(d,p). The potential energy profiles for both nucleophilic substitution (SN2) and elimination (E2) pathways have been investigated. The C Cl bond for the tertiary butyl system is significantly longer than the other alkyl groups. Calculated potential energy barrier of the backside (SN2B) substitution reactions for HCl/RClH+ system decreases in the order: Me > Et > Pri > But. The frontside substitution (SN2F) reaction barrier is higher than the backside substitution (SN2B) reaction barriers, but the difference between the SN2F and SN2B becomes smaller when the number of methyl substituents increases. Elimination reactions (E2) are thermodynamically unfavorable. |
| Databáze: | OpenAIRE |
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