Ab initio computational modeling on the tautomerism of monochalcogenocarboxylic acids CH3C(O)XH (X = S, Se, and Te) in the polar and aprotic solution
Ab initio computational modeling on the tautomerism of monochalcogenocarboxylic acids CH3C(O)XH (X = S, Se, and Te) in the polar and aprotic solution
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DOI：
10.1002/qua.21218
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发表时间：
2007
影响因子：
2.2
通讯作者：
Qiang-Gen Li;Guoming Liang;Xin Wang;S. Chu;Yi Ren
中科院分区：
文献类型：
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作者：
Qiang-Gen Li;Guoming Liang;Xin Wang;S. Chu;Yi Ren
通过从头算分子轨道方法（HF 和 MP2），使用 6-311+G(d,p) 和 6-311++G(2df,2pd) 基组，对极性和非质子溶液四氢呋喃 (THF) 中三种单硫族羧酸 CH3C(O)XH（X = S、Se 和 Te）的互变异构进行了计算建模 使用组合的超分子/连续体方法，其中 CH3OCH3 被认为是超分子中 THF 的现实模型。我们的计算表明，涉及 CH3OCH3 的互变异构不仅在互变平衡中优先选择烯醇形式 CH3C(X)OH（X = S、Se 和 Te），而且还显着降低了 THF 溶液中互变异构势垒 >34 kJ/mol。这些结果支持了 Kato 和同事的实验，与早期 Delaere 等人对硫代甲酸 HC(O)SH…O(CH3)2 互变异构势垒的理论预测相反，其中由于互变异构过渡结构定位的限制，势垒相对于反应物复合物增加了~6 kJ/mol。 © 2006 Wiley periodicals, Inc. Int J Quantum Chem，2007
Computational modeling by an ab initio molecular orbital method (HF and MP2) with the 6-311+G(d,p) and 6-311++G(2df,2pd) basis sets on the tautomerism of three monochalcogenocarboxylic acids CH3C(O)XH (X = S, Se, and Te) in the polar and aprotic solution tetrahydrofuran (THF) was undertaken using the combined supramolecular/continuum method, in which CH3OCH3 was considered as a realistic model for THF in the supermolecule. Our calculations showed that the tautomerism involving CH3OCH3 not only gives the preference of the enol form CH3C(X)OH (X = S, Se, and Te) in the tautomeric equilibrium, but also significantly lowers the tautomeric barriers by >34 kJ/mol in THF solution. These results support the experiments of Kato and coworkers, in contrast with earlier Delaere et al.'s theoretical prediction for the tautomeric barrier of thioformic acid HC(O)SH…O(CH3)2, in which the barrier is increased by ∼6 kJ/mol relative to reactants complex because of the constraint in locating the tautomeric transition structure. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007