Yang Sha, Wang Xinyao, Chu Han, Liu Wei
Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Inorg Chem. 2024 Apr 15;63(15):6836-6844. doi: 10.1021/acs.inorgchem.4c00257. Epub 2024 Apr 3.
Endohedral metallofullerenes show great promise as molecular-scale memory units due to their robust architecture and protective capability for encapsulated atoms. However, the flat potential-energy surface within the cage often results in a severe disorder of encapsulated atoms. Here, we focused on prototypical systems involving Li@C on metallic surfaces, emphasizing the electrode's confinement effect on caged dynamics. We demonstrated that the varying interfacial stabilities induced by Li motion predominantly depend on the synergetic effect of van der Waals forces and covalent bonds rather than the previously assumed electrostatic interactions. We unveiled that the repulsion effect between encapsulated atom and the metal electrode primarily arises from the antibonding states between the metal states below the Fermi level and the degenerated frontier orbitals from HOMO-4 to HOMO. By manipulating orbital interactions, we observed an ordered arrangement of the encapsulated atom on Rec-Pt(111) at room temperature. Furthermore, our findings underscore the disruptive influence of electric fields on the stability of distinct Li positions, a phenomenon closely tied to the dipole moment induced by Li motion. This research provides a new perspective on the confined internal dynamics of endohedral metallofullerenes by manipulating cage-electrode interactions, contributing to precisely controlled molecular electronics.
由于其坚固的结构和对封装原子的保护能力，内嵌金属富勒烯作为分子尺度的存储单元显示出巨大的潜力。然而，笼内平坦的势能面常常导致封装原子的严重无序。在这里，我们聚焦于涉及金属表面上Li@C的典型体系，强调电极对笼内动力学的限制作用。我们证明，由Li运动引起的不同界面稳定性主要取决于范德华力和共价键的协同效应，而非先前假定的静电相互作用。我们揭示，封装原子与金属电极之间的排斥效应主要源于费米能级以下的金属态与从HOMO - 4到HOMO的简并前沿轨道之间的反键态。通过操纵轨道相互作用，我们在室温下观察到了Rec - Pt(111)上封装原子的有序排列。此外，我们的研究结果强调了电场对不同Li位置稳定性的破坏影响，这一现象与Li运动诱导的偶极矩密切相关。这项研究通过操纵笼 - 电极相互作用，为内嵌金属富勒烯的受限内部动力学提供了新的视角，有助于实现精确控制的分子电子学。
