Yi Qiuhao, Yu Xinlei, Lei Xin, Geng Lijun, Jia Yuhan, Cheng Longjiu, Luo Zhixun
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Phys Chem A. 2023 Apr 6;127(13):2912-2920. doi: 10.1021/acs.jpca.3c00673. Epub 2023 Mar 28.
Well-resolved Nb clusters are produced and reacted with ethene and propene via a downstream flow tube reactor. Interestingly, the Nb clusters readily react with ethene and propene to form dehydrogenation products; however, Nb shows up in the mass spectra with prominent mass abundance indicating its inertness to react with olefins. For this cluster, we conduct photoelectron velocity map imaging (VMI) experiments and verify the stability of Nb within a highly symmetrical rhombic dodecahedron structure. Theoretical studies show that the stability of the Nb cluster is correlated with its superatomic nature pertaining to both geometric and electronic shell closures. Notably, the superatomic 1s orbital is dominated by the 5s electron of the central Nb atom, while the other superatomic orbitals are contributed by s-d hybridization, especially a remarkable contribution of s-d hybridization. Apart from the closed shells, the highly symmetric geometry of Nb is associated with a regular polyhedral structure directed by all rhombus facets, embodying a magic number for body-centered dodecahedra, indicative of enhanced stability as a double magic cluster free of olefin adsorption.
通过下游流动管反应器制备出分辨率良好的铌团簇，并使其与乙烯和丙烯发生反应。有趣的是，铌团簇很容易与乙烯和丙烯反应形成脱氢产物；然而，铌在质谱图中以显著的质量丰度出现，表明其与烯烃反应的惰性。对于该团簇，我们进行了光电子速度映射成像（VMI）实验，并验证了铌在高度对称的菱形十二面体结构中的稳定性。理论研究表明，铌团簇的稳定性与其超原子性质相关，这涉及几何和电子壳层的封闭。值得注意的是，超原子1s轨道由中心铌原子的5s电子主导，而其他超原子轨道则由s-d杂化贡献，特别是s-d杂化的显著贡献。除了封闭壳层外，铌的高度对称几何结构与由所有菱形面定向的规则多面体结构相关，体现了体心十二面体的幻数，表明作为无烯烃吸附的双幻团簇稳定性增强。
