Claveau Emily E, Miliordos Evangelos
Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
Phys Chem Chem Phys. 2021 Sep 29;23(37):21172-21182. doi: 10.1039/d1cp02492b.
Multi-reference electronic structure calculations combined with large basis sets are performed to investigate the electronic structure of the ground and low-lying electronic states of the MO diatomic species with M = Ti-Cu. These systems have shown high efficiency in the activation of the C-H of saturated hydrocarbons. This study is the first systematic and accurate work for these systems and our results and discussion provides insights into the reactivity and stability of MO units. We find that they can be divided in three groups. The early transition metals (Ti, V, Cr) have very stable and well separated oxo (MO) character ground states, the middle transition metals (Mn, Fe) have oxyl (MO˙) ground states with low-lying oxo excited states, and the late transition metals (Co, Ni, Cu) have well separated oxyl states. The reported spectroscopic constants will aid future experimental investigations, which are sparse in the literature. Periodic trends for the bond lengths, energetics, excitation energies, and wavefunction composition are discussed in detail. Complete basis set limit results indicate the high accuracy of the quintuple- basis sets.
结合大基组进行多参考电子结构计算，以研究M = Ti - Cu的MO双原子物种的基态和低电子态的电子结构。这些体系在饱和烃的C - H活化中表现出高效性。本研究是针对这些体系的首个系统且精确的工作，我们的结果和讨论为MO单元的反应性和稳定性提供了见解。我们发现它们可分为三组。早期过渡金属（Ti、V、Cr）具有非常稳定且分离良好的氧代（MO）特征基态，中期过渡金属（Mn、Fe）具有氧自由基（MO˙）基态且有氧代激发态，晚期过渡金属（Co、Ni、Cu）具有分离良好的氧自由基态。所报道的光谱常数将有助于未来的实验研究，而此类研究在文献中较为稀少。详细讨论了键长、能量、激发能和波函数组成的周期性趋势。完全基组极限结果表明五重基组具有高精度。
