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How water molecules modulate the hydration of CO 2 in water solution: Insight from the cluster‐continuum model calculations
Author(s) -
Wang Binju,
Cao Zexing
Publication year - 2012
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.23144
Subject(s) - chemistry , molecule , dissociation (chemistry) , proton , cluster (spacecraft) , chemical physics , water dimer , reaction mechanism , self ionization of water , solvent , computational chemistry , hydrogen bond , catalysis , organic chemistry , physics , quantum mechanics , computer science , programming language
The hydration of CO 2 in water solution was investigated by the cluster‐continuum model calculations with n = 1–8 water molecules. For n = 1–4 water molecules, all the reactions follow a concerted pathway to the hydration product directly. For n = 5–8 water molecules, all the reactions follow a stepwise mechanism and a labile H 3 O + intermediate is involved in reaction. The surrounding water molecules from the bulk solvent play a key role in the proton relay process, which can stabilize the charged transition state and the H 3 O + intermediate in reaction. Furthermore, if the proton transfer from H 3 O + to the carbonyl oxygen occurs, the hydration pathway will be followed. If there is a proton transfer from H 3 O + to the outer water phase through the water bridge, the dissociation product of HCO 3 − will be formed. The predicted reaction energetics by current cluster‐continuum model calculations shows good agreement with the experimental values. Present calculations strongly suggest the suitable cluster‐continuum model including more explicit water molecules highly required for reasonable and unbiased description of the proton relay mechanism for proton transfer related reactions in water solution. © 2012 Wiley Periodicals, Inc.