Quantum-Chemical Predictions of pK(a)'s of Thiols in DMSO

Abstract : The deprotonation of thiols (on the S-H bond) is widely involved in organic and bio-organic reactions. With the aid of density functional theory (DFT) calculations, the present study focuses on predicting the pK(a)'s of thiols. Efforts were first put in searching for an appropriate computational method. To achieve this goal, the accuracy of 13 different DFT functionals (i.e., B3LYP, BB1K, PBE, M06, M05, M06-2X, M06-L, M05-2X, TPSS, MPW1K, MPWB1K, MPW3LYP, TPSSLYP1W) and 6 different total electron basis sets (6-31G(d), 6-31+G(d), 6-31+G(d,p), 6-311+G(d,p), 6-311++G(d,p), 6-311++G(2df,2p)) (with DMSO solvent and SMD solvation model) were examined. The M06-2X/6-311++G(2df,2p) (M1) method was found to give the best performance in reproducing the reported 16 pK(a)'s of thiols, with a standard deviation (SD) of about 0.5 pK(a) unit. Meanwhile, the M1 method was found to be excellent in reproducing the gas phase Gibbs free energies of 17 thiols, providing extra evidence for the reliability of the M1 method in treating thiol systems. On this basis, M1 was then used to predict the pK(a)'s of 291 thiols whose experimental pK(a) values remain unknown. Accordingly, the scope of pK(a)'s of different thiols was constructed.
Type de document :
Article dans une revue
Journal of Physical Chemistry A, American Chemical Society, 2014, 118 (3), pp.606-622. 〈10.1021/jp410274n〉
Domaine :
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Soumis le : jeudi 18 février 2016 - 16:39:49
Dernière modification le : jeudi 6 septembre 2018 - 16:00:03

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Hai-Zhu Yu, Yi-Meng Yang, Liang Zhang, Zhi-Min Dang, Guo-Hua Hu. Quantum-Chemical Predictions of pK(a)'s of Thiols in DMSO. Journal of Physical Chemistry A, American Chemical Society, 2014, 118 (3), pp.606-622. 〈10.1021/jp410274n〉. 〈hal-01276053〉

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