Prediction of the Standard Gibbs Energy of Transfer of Organic Ions Across the Interface between Two Immiscible Liquids

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• 作者：Toshiyuki Osakai ; Yasuhiro Naito ; Kazuo Eda ; Masahiro Yamamoto
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：October 15, 2015
• 年：2015
• 卷：119
• 期：41
• 页码：13167-13176
• 全文大小：501K
• ISSN：1520-5207

文摘

The non-Bornian solvation model was applied for evaluation of the standard Gibbs energy (螖G_tr^掳,W鈫扥) of transfer of organic ions from water (W) to organic solvent (O = nitrobenzene). The solvation energy of an ion in either W or O is basically formulated as the energy required for the formation of a nanosized ion鈥搒olvent interface around the ion; however, many organic ions with strongly charged groups (e.g., 鈭扴O₃^{鈥?/sup>, 鈭扖O₂鈥?/sup>, 鈭扤H₃+) are preferentially hydrated in O. Here we divided the surface of an ion into 鈥渉ydrated鈥?and 鈥渘on-hydrated鈥?surfaces and then carried out regression analyses with experimental values of 螖G_tr掳,W鈫扥. In the analyses, the local electric field on the surface of an organic ion was evaluated through density functional theory calculation. Good regression results were then obtained with the mean absolute error of 1.9 and 2.4 kJ mol鈥? for 34 anions and 63 cations, respectively. These errors correspond to the error of 鈭?0 mV in the standard ion-transfer potential (螖_OW蠒掳), being only two times larger than the typical experimental error (鈭?0 mV) in the voltammetric measurement. This non-Bornian model is promising for theoretical prediction of 螖G_tr掳,W鈫扥 (or 螖_OW蠒掳) for organic ions and possibly of the biomembrane permeability for ionic drugs.}