School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China.
J Mol Model. 2013 Sep;19(9):4003-12. doi: 10.1007/s00894-013-1932-7. Epub 2013 Jul 13.
Density functional theory (DFT) with relativistic corrections of zero-order regular approximation (ZORA) has been applied to explore the reaction mechanisms of ethane dehydrogenation by Zr atom with triplet and singlet spin-states. Among the complicated minimum energy reaction path, the available states involves three transition states (TS), and four stationary states (1) to (4) and one intersystem crossing with spin-flip (marked by -->): (3) Zr + C 2 H 6 → (3) Zr-CH 3 -CH 3 ((3)1) → (3)TS 1/2 → (3) ZrH-CH 2 -CH 3 ((3)2) → (3) TS 2/3 --> (1) ZrH2-CH2 = CH2 ((1) 3) → (1) TS 3/4 → (1) ZrH 3 -CH = CH 2 ((1)4). The minimum energy crossing point is determined with the help of the DFT fractional-occupation-number (FON) approach. The spin inversion leads the reaction pathway transferring from the triplet potential energy surface (PES) to the singlet's accompanying with the activation of the second C-H bond. The overall reaction is calculated to be exothermic by about 231 kJ mol(-1). Frequency and NBO analysis are also applied to confirm with the experimental observed data.
密度泛函理论（DFT）与零阶正则逼近（ZORA）的相对论修正已被应用于探索三重态和单重态Zr 原子与乙烷脱氢的反应机制。在复杂的最低能量反应路径中，涉及三个过渡态（TS），四个稳定态（1）至（4）和一个自旋翻转的体系间交叉（标记为-->:（3）Zr+C2H6→（3）Zr-CH3-CH3（（3）1）→（3）TS1/2→（3）ZrH-CH2-CH3（（3）2）→（3）TS2/3--->（1）ZrH2-CH2=CH2（（1）3）→（1）TS3/4→（1）ZrH3-CH=CH2（（1）4）。借助 DFT 分数占据数（FON）方法确定了最小能量交叉点。自旋反转导致反应途径从三重态势能面（PES）转移到单重态，同时第二 C-H 键被激活。整个反应被计算为放热约 231 kJ mol(-1)。还应用了频率和 NBO 分析来与实验观察到的数据进行确认。
