Cui Chaonan, Jia Yuhan, Zhang Hanyu, Geng Lijun, Luo Zhixun
Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China.
University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
J Phys Chem Lett. 2020 Oct 1;11(19):8222-8230. doi: 10.1021/acs.jpclett.0c02218. Epub 2020 Sep 16.
Dinitrogen activation is known as one of the most challenging subjects in chemistry. A number of well-defined metal complexes, nitrides, and clusters have been studied that show catalysis for dinitrogen activation. However, direct evidence of a complete cleavage of the N≡N triple bond at mild conditions is rather limited to date. Herein, we report a study on the dissociation of N on small rhodium clusters assisted by surface plasma radiation. From mass spectrometry observation, a few rhodium nitride clusters with an odd number of nitrogen atoms are produced, such as the RhN ( = 1-5) series, indicative of N≡N bond dissociation in the mild plasma atmosphere. Interestingly, RhN is identified with outstanding mass abundance among the RhN products, and its ground-state structure is in the form of RhN(N) by capping a nitrogen atom on the top of Rh plane and hanging three N molecules beneath the three Rh atoms respectively, giving rise to a symmetry and excellent stability. We demonstrate the catalysis of such a three-atom rhodium cluster and reveal a dinitrogen activation strategy by thermodynamics- and dynamics- favorable chain reactions of multiple N molecules with two rhodium clusters under plasma atmosphere.
二氮活化是化学领域中最具挑战性的课题之一。人们已经研究了许多结构明确的金属配合物、氮化物和团簇，它们显示出对二氮活化的催化作用。然而，迄今为止，在温和条件下N≡N三键完全断裂的直接证据相当有限。在此，我们报道了一项关于表面等离子体辐射辅助下小铑团簇上N解离的研究。通过质谱观察，产生了一些氮原子数为奇数的氮化铑团簇，如RhN（ = 1-5）系列，这表明在温和的等离子体气氛中N≡N键发生了解离。有趣的是，在RhN产物中，RhN具有显著的质量丰度，其基态结构为RhN(N)，即一个氮原子覆盖在Rh平面顶部，三个N分子分别悬挂在三个Rh原子下方，呈现出一种对称性且稳定性极佳。我们展示了这种三原子铑团簇的催化作用，并揭示了在等离子体气氛下多个N分子与两个铑团簇通过热力学和动力学有利的链式反应实现二氮活化的策略。
