How water molecules modulate the hydration of CO2 in water solution: insight from the cluster-continuum model calculations.
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.
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 360015, China.
Binju
B
Wang
Zexing
Z
Cao
D002245:Carbon Dioxide / Q000737:chemistry*; D015394:Molecular Structure; D011789:Quantum Theory; D012996:Solutions; D014867:Water / Q000737:chemistry*
D012996:Solutions; D014867:Water; D002245:Carbon Dioxide