State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
J Am Soc Mass Spectrom. 2019 Oct;30(10):1956-1963. doi: 10.1007/s13361-019-02226-2. Epub 2019 Jun 24.
Dinitrogen (N) activation by metal hydride species is of fundamental interest and practical importance while the role of hydrogen in N activation is not well studied. Herein, the structures of CoD (n = 0-4) clusters and their reactions with N have been studied by using a combined experimental and computational approach. The mass spectrometry experiments identified that the CoD (n = 2-4) clusters could adsorb N while the CoD (n = 0 and 1) clusters were inert. The photoelectron imaging spectroscopy indicated that the electron detachment energies of CoD are smaller than those of CoD, which characterized that it is easier to transfer electrons from CoD than from CoD to activate N. The density functional theory calculations generally supported the experimental observations. Further analysis revealed that the H atoms in the CoH (n = 2-4) clusters generally result in higher energies of the Co 3d orbitals in comparison with the CoH (n = 0 and 1) systems. By forming chemical bonds with H atoms, the Co atoms of CoH are less negatively charged with respect to the naked Co system, which leads to higher N binding energies of CoHN than that of CoN.
二氮（N）的金属氢化物物种的激活具有基础的研究兴趣和实际重要性，而氢在 N 激活中的作用尚未得到很好的研究。在此，采用实验和计算相结合的方法研究了 CoD（n=0-4）团簇及其与 N 的反应。质谱实验表明，CoD（n=2-4）团簇可以吸附 N，而 CoD（n=0 和 1）团簇则不反应。光电子成像光谱表明，CoD 的电子离解能小于 CoD，这表明从 CoD 向 N 转移电子比从 CoD 更容易激活 N。密度泛函理论计算通常支持实验观察。进一步的分析表明，与 CoH（n=0 和 1）体系相比，CoH（n=2-4）团簇中的 H 原子通常导致 Co 3d 轨道的能量更高。通过与 H 原子形成化学键，相对于裸露的 Co 体系，CoH 中的 Co 原子带负电荷更少，这导致 CoHN 的 N 结合能高于 CoN。
