In-Depth Theoretical Probe into Novel Mixed-Metal Uranium-Based Endohedral Clusterfullerenes Sc₂UX@I_h(31924)-C₈₀ (X = C, N)

Abstract

Mixed-metal uranium-based endohedral clusterfullerenes, Sc2UX@C80 (X = C, N), which were recently reported in experiments, have been investigated considering heptagon-containing isomers by density functional theory calculations in conjunction with statistical thermodynamic analysis. The triplet Sc2UC@I h (31924)-C80 and quartet Sc2UN@I h (31924)-C80, named after the spiral number (31924), are found to be thermodynamically stable and satisfy aromaticity rules. Furthermore, the restricted movements of the Sc2UX (X = C, N) cluster in I h (31924)-C80 have been demonstrated via ab initio molecular dynamics simulations. The six-electron transfer from the inner cluster to the cage results in the electronic structures (Sc2UX)6+@C80 6– (X = C, N), which were also confirmed by natural bond orbital analysis. On the basis of the frontier molecular orbitals, the oxidation states of uranium in Sc2UC@C80 and Sc2UN@C80 are +IV and +III, respectively, with residual electrons in 5f orbitals of U. The chemical bond between U and C (N) of the inner cluster is characterized as a double bond (single bond) by an analysis of the Mayer bond orders. There are covalent interactions between the inner cluster and outer cage, which is clarified by the quantum theory of atoms in molecules. IR spectra of the optimal isomers have also been simulated, which show the clear difference between Sc2UX@C80 (X = C, N). These findings, together with simulated results, are expected to supply useful information in future experiments of mixed-metal uranium-based endohedral clusterfullerenes.

The Structure–Property Correlations in the Isomerism of Au21(SR)15 Nanoclusters by Density Functional Theory Study

“…The Kohn–Sham (KS) orbitals were calculated with the PBE functional on Gaussian 09 software, with the effective core potential of LANL2DZ basis set for Au and 6‐31G* basis set for all other atoms. The Mayer and Wiberg bond order was calculated with ADF and Gaussian software, respectively. The two types of bond order are consistent in evaluating the relative bond strengths of the isomerism.…”

“…[49] The Kohn-Sham (KS)o rbitals were calculated with the PBE functional on Gaussian09s oftware, [50] with the effective core potentialo f LANL2DZ basis set [39] for Au and 6-31G* basis set for all other atoms. The Mayer [51] and Wiberg [52] bond order was calculated with ADF andG aussians oftware, respectively.T he two types of bond order are consistenti ne valuating the relative bond strengthso ft he isomerism.F or clarity,o nly the Mayer bond order are provided in Table 1, and the detailed results of the Wiberg bond order are given in Ta ble S2. The singlep oint calculations on Partial density of states (PDOS) [53] were performed with Dmol3 software.…”

Discovery of Non-Isolated-Pentagon-Rule Fullerenes from Computational Characterization of U2O@C72

“…However, their presence is suggested to be determined by kinetic factor, namely, the formation and yield cannot be well explained/predicted by thermodynamic calculations. In addition, Zhao et al’s recent series of theoretical calculations regarding different U-based EMFs all indicate that the possibility of any heptagon-containing isomer can be completely ignored. ,, Thus, it is reasonable that we did not consider such nonclassical isomers as the candidate cages in this work.…”

“…Encouragingly, great progress has been made in the last four years since the successful synthesis and structural characterization of Th@ C 3 v (8)-C 82 . Especially, the reported internal uranium-based contents have covered monoatom (U@ D 3 h (1)-C 74 , U@ C 1 (17418)-C 76 , U@ C 1 (28324)-C 80 , U@ C 2 (5)-C 82 , U@ C 2 v (9)-C 82 , U@ D 2 (21)-C 84 , U@ C s (15)-C 86 , and U@C 1 (11)-C 86 ), diatom (U 2 @ I h (7)-C 80 ) , , and metal cluster (Sc 2 CU@ I h (7)-C 80 , , Sc 2 NU@ I h (7)-C 80 , , U 2 C@ I h (7)-C 80 , , U 2 N@ I h (7)-C 80 , U 2 C 2 @ D 3 h (5)-C 78 , and U 2 C 2 @ I h (7)-C 80 ) . Very recently, the first carbene derivatives of Th@ C 3 v (8)-C 82 and U@ C 2 v (9)-C 82 were successfully achieved with high reactivity due to the strong metal-cage interplay, opening the route toward chemical functionalization of actinide EMFs …”

U2N@Ih(7)-C80: fullerene cage encapsulating an unsymmetrical U(iv)NU(v) cluster

“…Encouraged by the recent advances made in actinide fullerenes, 13–15,22–25 we further expanded our exploration to the NCFs. Herein, for the first time, we report the successful synthesis and full characterization of U 2 N@ I h (7)-C 80 , an unexpected dimetallic nitride clusterfullerene which violates the long standing TNT stoichiometry.…”