A Multilayered Representation, Quantum Mechanical and Molecular Mechanics Study of the CH3F+OH- Reaction in Water

作者：Chen, Jie^*; Xu, Yulong; Wang, Dunyou

来源：Journal of Computational Chemistry, 2014, 35(6): 445-450.

DOI：10.1002/jcc.23498

• quantum mechanical
• molecular mechanics
• S(N)2 reaction
• aqueous solution
• potential mean force
• barrier height
• reaction pathway
• nucleophile

The bimolecular nucleophilic substitution (S(N)2) reaction of CH3F+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 approximate to 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.

• 出版日期2014-3-5
• 单位山东师范大学