【公開日：2023.07.31】【最終更新日：2023.05.17】
課題データ / Project Data
課題番号 / Project Issue Number
22MS0020
利用課題名 / Title
Theoretical Studies on Endohedral Metal-Metal-Bonding Fullerenes Lu2@C2n (2n = 76 - 84) and Their Two-Dimensional Nanomaterials
利用した実施機関 / Support Institute
自然科学研究機構 分子科学研究所
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）物質・材料合成プロセス/Molecule & Material Synthesis（副 / Sub）計測・分析/Advanced Characterization
【重要技術領域 / Important Technology Area】（主 / Main）マテリアルの高度循環のための技術/Advanced materials recycling technologies（副 / Sub）次世代ナノスケールマテリアル/Next-generation nanoscale materials
キーワード / Keywords
endohedral fullerenes, DFT calculations, QTIAM, EDA-NOCV
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Tao Yang
所属名 / Affiliation
School of Physics, Xi'an Jiaotong University
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
Yuan Shui,Gao-Lei Hou
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
江原 正博
利用形態 / Support Type
（主 / Main）共同研究/Joint Research（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Endohedral metal−metal-bonding fullerenes, in which the encapsulated metals form covalent metal−metal bonds inside, are one kind of emerging endohedral fullerenes. Herein, we reported quantum-chemical studies on the electronic structures, chemical bonding, and dynamic fluxionality behavior of endohedral metal−metal-bonding fullerenes Lu2@C2n (2n = 76−88). Multiple bonding analysis approaches including molecular orbital analysis, the natural bond orbital analysis (NBO), electron localization function (ELF), the adaptive natural density partitioning (AdNDP) analysis, and quantum theory of atoms in molecules (QTAIM) unambiguously revealed one two-center-two-electron σ covalent bond between two Lu ions in fullerenes. The energy decomposition analysis with the natural orbitals for chemical valence method (EDA-NOCV) on the bonding nature between encapsulated metal dimer and the fullerene cages suggested that two covalent bonds forms between the metal dimer and fullerenes, giving rise to a covalent bonding nature between the metal dimer and fullerene cage and a formal charge model of [Lu2]2+@[C2n]2–. For Lu2@C76, the dynamic fluxionality behavior of the metal dimer Lu2 inside fullerene C76 has been revealed via locating the transition state with an energy barrier of 5 kcal/mol. Further EDA calculations indicate that the energy barrier is controlled by a series of terms including geometric deformation energy, the electrostatic interaction, and the orbital interactions.
実験 / Experimental
Initial structures of Lu2@C2n (2n = 76−88) are taken from the experimental crystal structures. To find out the reliable functional, some popular functionals including BP86-D3, PBE-D3, TPSS-D3, PBE0-D3, B3LYP-D3, M06-D3, and ωB97X-D3 within Grimme’s dispersion corrections have been selected for test geometry optimization on Lu2@C76. The valence triple-zeta polarization basis set def2-TZVP was employed for both C and Lu, in which the small-core energy-consistent relativistic effective core potential (ECP) def2-ECP were employed to describe the 28 core electrons of Lu. To further evaluate the computational accuracy of electronic properties, single-point energy calculations were conducted at the Douglas-Kroll-Hess (DKH) second order scalar-relativistic scheme by using PBE-D3 functional in combination with the all-electron relativistic correlation-consistent polarized triple-zeta basis sets for C (cc-pVTZ-DK) and Lu (cc-pVTZ-DK3) on PBE-D3/def2-TZVP-optimized geometries. The energy decomposition analysis developed by Ziegler and Rauk is one of powerful methods to study the nature of the chemical bonds. Here, the metal−cage bonding situation was also studied via energy decomposition analysis (EDA) together with the natural orbitals for chemical valence (NOCV) method, denoted by EDA-NOCV.
結果と考察 / Results and Discussion
FIG. 1 depicts the optimized geometries of all Lu2@C2n (2n = 76−88). The optimized geometries agree well with their crystal structures. We also examined the singlet-triplet splitting energy ES-T to confirm the electronic ground state of the Lu2@C2n. To assess their capacity to accept and donate electrons, the vertical electron affinity (VEA), adiabatic electron affinity (AEA), vertical ionization potential (VIP), and adiabatic ionization potential (AIP) for all the EMFs were computed. Natural partially charges (q) of Lu atoms and Wiberg bond order are also analyzed to examine the charge distributions and bonding nature. We further analyzed the chemical bonding in the Lu2@C2n by using the adaptive natural density partitioning (AdNDP) approach and electron localization function (ELF) map. The EDA-NOCV numerical results for all the Lu2@C2n with [Lu2]2+ (triplet) and C2n2– (triplet) as interacting fragments are calculated to elucidate the bonding interaction. The dynamic fluxionality behavior of the Lu2 dimer undoubtedly influences the chemical bonding between the Lu2 dimer and C76. Here, the isomerization transition state (TS) connecting equivalent configurations has been successfully located. The intrinsic reaction coordinate (IRC) has also been calculated to acquire a minimum energy path (MEP) that connects TS, reactant and product.
図・表・数式 / Figures, Tables and Equations
FIG. 1. Optimized molecular structures of Lu2@C2n (2n = 76−88).
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
-
Yuan Shui, Understanding electronic structures, chemical bonding, and fluxional behavior of Lu2@C2n (2n = 76–88) by a theoretical study, The Journal of Chemical Physics, 157, (2022).
DOI: doi.org/10.1063/5.0100652
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- 1.Chinese Physics Society 2022 Fall Meeting, China, 2022, Nov. 17-20
- 2.The 3rd Symposium on Cluster Science and Atomic Manufacturing, China, 2022, Aug. 6-8
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件