Benchmarking of Density Functionals for the Accurate Description of Thiol鈥揇isulfide Exchange

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• 作者：Rui P. P. Neves ; Pedro A. Fernandes ; Ant贸nio J. C. Varandas ; Maria J. Ramos
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2014
• 出版时间：November 11, 2014
• 年：2014
• 卷：10
• 期：11
• 页码：4842-4856
• 全文大小：578K
• ISSN：1549-9626

文摘

A set of 92 density functionals was employed to accurately characterize thiol鈥揹isulfide exchange. The properties we have benchmarked throughout the study include the geometry of a 15 atoms model system, the potential energy surface, the activation barrier, and the energy of reaction for thiol鈥揹isulfide exchange. Reference energies were determined at the CCSD(T)/CBS//MP2/aug-cc-pVDZ level of theory, and reference geometries were calculated at the MP2/aug-cc-pVTZ level. M11-L, M06-2X, M06-HF, N12-SX, PBE1PBE, PBEh1PBE, and OHSE2PBE described better the geometry of the model system, with average deviations of 0.06 脜 in bond lengths (0.06 脜 in bond-breaking lengths) and 1.9掳 in bond angles. On the other hand, the potential energy surface and its gradient were more accurately described by the hybrid density functional BHandH, closely followed by mPW1N, mPW1K, and mPWB1K. The barrier height and energy of reaction were better reproduced by the BMK and M06-2X functionals (deviations of 0.17 and 0.07 kcal路molp>鈥?p>, respectively) for a set of 10 Pople鈥檚 basis sets. MN12-SX and M11-L showed very good results for the widely used 6-311++G(2d,2p) basis set, with deviations of 0.02 and 0.05 kcal路molp>鈥?p>, respectively. We studied the effect of the split-valence, diffuse, and polarized functions in the activation barrier of thiol鈥揹isulfide exchange, for a set of 10 Pople鈥檚 basis sets. While increasing the splitting and polarization may increase the activation barrier in approximately 1 kcal路molp>鈥?p>, diffuse functions generally contribute to decreasing it no more than 0.10 kcal路molp>鈥?p>. In general, 13 functionals provided energies within 1 kcal路molp>鈥?p> of the reference value. The BB1K density functional is one of the best density functionals to characterize thiol鈥揹isulfide exchange reactions; however, several density functionals with modified Perdew鈥揥ang exchange and about 40% Hartree鈥揊ock exchange, such as mPW1K, mPW1N, and mPWB1K, show a good performance, too.