密度泛函理论研究S-亚硝基硫醇化合物中S-NO的键离解能的取代基效应(英文)

DFT Study of the Substituent Effect on Bond Dissociation Enthalpies(BDE) of the S-NO Bond for S-nitrosothiols

利用密度泛函理论（B3LYP，B3PW91，B3P86），使用6—31G^＊＊基组计算了乙氰溶液中孓亚硝基硫醇化合物中SNO的键离解能。结果表明B3PW91／G-31G^＊＊方法计算得出的键离解能平均绝对偏差为7．36kJ／mol，与实验符合比较好。因此，我们建议使用B3PW91／6—31G^＊＊方法来计算S-亚硝基硫醇化合物中S-NO的键离解能。进一步分析表明不同的取代基对S-NO的键离解能影响不同。当C6H5SNO中的一个H基团分别被2-CH3、4-CH3、4-Cl、4-NO2基组取代时，S-NO的键离解能降低2．09～12．54kJ／mol。当C6H5SNO中的一个H基团分别被2-Cl、3-CH3、3-Cl、4-OCH3基组取代时，S-NO的键离解能增加0．042～36．37kJ／mol。

Quantum chemical calculations are used to estimate the bond dissociation energies （BDEs） for 11 S-nitrosothiols compounds. These compounds are studied by employing the hybrid density functional theory （B3LYP, B3PWg1, B3P86） methods together with 6-31G^＊＊ basis set. It is demonstrated that the B3PWg1/6-31G^＊ ＊ method can give good results of BDE, which has the mean absolute error of 7. 36 kJ/mol. Considering the smaller mean absolute error at 6- 31G^＊ ＊ , we recommend the B3PW91 method combined with 6-31G^＊ ＊ basis set, as a satisfactory method of computing the BDEs for removal of the NO group in RSNO compounds. Further analysis indicated that different substituent positions have different effect on BDE of the S-NO bond. The bond dissociation energy of the S-NO bond lowers 2.09-12.54 kJ/mol when a H group of C6H5SNO is substituted with 2-CH3, 4-CH3, 4-C1, 4-NO2 groups, respectively. While the bond dissociation energy of the S-NO bond increases 0. 042-36. 37 kJ/mol when a H group of C6H5SNO is substituted with 2-C1, 3-CH3, 3-Cl, 4-OCH3 groups, respectively.