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A multilayered representation, quantum mechanical and molecular mechanics study of the CH 3 F + OH − reaction in water
Author(s) -
Chen Jie,
Xu Yulong,
Wang Dunyou
Publication year - 2013
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.23498
Subject(s) - solvation , aqueous solution , chemistry , molecular mechanics , activation energy , nucleophile , transition state theory , computational chemistry , reaction mechanism , quantum , thermodynamics , transition state , potential of mean force , molecular dynamics , molecule , reaction rate constant , quantum mechanics , physics , kinetics , organic chemistry , catalysis
The bimolecular nucleophilic substitution (S N 2) reaction of CH 3 F + OH − in aqueous solution was investigated using a combined quantum mechanical and molecular mechanics approach. Reactant complex, transition state, and product complex along the reaction pathway were analyzed in water. The potentials of mean force were calculated using a multilayered representation with the DFT and CCSD(T) level of theory for the reactive region. The obtained free energy activation barrier for this reaction at the CCSD(T)/MM representation is 18.3 kcal/mol which agrees well with the experimental value at ∼21.6 kcal/mol. Both the solvation effect and solute polarization effect play key roles on raising the activation barrier height in aqueous solution, with the former raising the barrier height by 3.1 kcal/mol, the latter 1.5 kcal/mol. © 2013 Wiley Periodicals, Inc.