Nie Yu-Xiu, Zhang Xiao-Xia, Yuan Yong-Ning, Lu Feng, Geng Zhi-Yuan
College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070, Gansu, People's Republic of China.
J Mol Model. 2020 Apr 3;26(5):91. doi: 10.1007/s00894-020-04357-w.
The mechanism of C-H bond activation of ethane was catalyzed by palladium halide cations (PdX (X = F, Cl, Br, H, and CH)), which was investigated using density functional theory (DFT) at B3LYP level. The reaction mechanism was taken into account in triplet and singlet spin state potential energy surfaces. For PdF, PdCl, and PdBr, the high spin states were the ground states, whereas the ground states were the low spin states in PdH and PdCH. The reaction of PdF, PdCl, and PdBr with ethane occurred via a typical "two-state reactivity" mechanism. In contrast, for PdH and PdCH, the overall reaction performed on the ground state PESs in a spin-conserving manner. The crossing points between two potential energy surfaces were observed and effectively decreased the activation barrier in PdX/CH (X = F, Cl, and Br). The minimum energy crossing points (MECP) were obtained used the algorithm in Harvey method. The natural valence electron configuration calculations were analyzed by natural bond orbital. The distribution and contribution of the front molecular orbital of the initial complexes could be further understand by the density of states. The feature of the bonding evolution in the main pathways was studied using topological analysis including localized orbital locator and atoms in molecules.
卤化钯阳离子（PdX，X = F、Cl、Br、H和CH）催化乙烷C-H键活化的机理，采用密度泛函理论（DFT）在B3LYP水平上进行了研究。在三重态和单重态自旋态势能面上考虑了反应机理。对于PdF、PdCl和PdBr，高自旋态是基态，而在PdH和PdCH中基态是低自旋态。PdF、PdCl和PdBr与乙烷的反应通过典型的“双态反应性”机理发生。相比之下，对于PdH和PdCH，整个反应以自旋守恒的方式在基态势能面上进行。观察到两个势能面之间的交叉点，有效降低了PdX/CH（X = F、Cl和Br）中的活化能垒。使用Harvey方法中的算法获得了最小能量交叉点（MECP）。通过自然键轨道对自然价电子构型计算进行了分析。通过态密度可以进一步了解初始配合物前沿分子轨道的分布和贡献。使用包括定域轨道定位器和分子中的原子在内的拓扑分析研究了主要途径中键合演化的特征。
