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. 2026 Sep 15;11(38):57491–57497. doi: 10.1021/acsomega.6c06001

Theoretical Insights into the Stability and Electronic Properties of Sc3N@C74

Yong-Xin Gu †,‡,*, Jia-Yi Wan †, Bai-Qiu Gao †, De-Huai Li †,‡, Meng-Yang Li §, Yong Guo †,‡
PMCID: PMC13628631  PMID: 42824579

Abstract

Endohedral metal nitride cluster fullerenes exhibit broad application prospects in fields such as electronics, catalysis, and biomedicines owing to their unique structures and physicochemical properties, while their macroscopic performance fundamentally depends on the microscopic bonding mechanism between the encapsulated clusters and the carbon cages. In this work, Sc3N@C74 is chosen as a representative model to systematically uncover the intrinsic interplay between the encapsulated Sc3N cluster and the C74 carbon cage, alongside the underlying structural and electronic characteristics governing this endohedral fullerene system. The thermodynamic stability, geometric structure, electron distribution, and chemical bonding characteristics were comprehensively analyzed using density functional theory calculations, and the results revealed that the most stable isomerSc3N@D 3h (14246)-C74satisfies the isolated-pentagon rule, exhibits pronounced electron transfer from the Sc3N cluster to the C74 cage, and extensive orbital hybridization. Furthermore, Mayer bond order analysis quantitatively confirmed a substantial covalent contribution to the Sc–C interactions. This synergistic bonding motifcharacterized by strong covalent bonding at the cluster-cage interface and mixed (covalent/ionic) interactions in the outer regionsestablishes a robust theoretical framework and rational design principle for predicting and engineering high-performance endohedral fullerene materials. Finally, the UV-vis-NIR simulation of the most stable isomer Sc3N@D 3h (14246)-C74 predicted its characteristic peaks, thereby establishing an experimentally verifiable quantitative theoretical basis for subsequent synthesis and spectral characterization.

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1. Introduction

Fullerene C74 is a highly significant and distinctive member of the carbon allotrope family. In contrast to its well-known counterparts, C60 (with a soccer-ball-like structure) and C70 (resembling a rugby ball), C74 has long remained poorly understood and enigmatic. In early experiments, researchers encountered significant challenges in isolating pure, empty C74 using chromatographic methods. Even in samples enriched with C74, the compound exhibited high instability and was prone to polymerization or degradation. This contributed to the prevailing view that isolated, hollow C74 molecules are inherently unstable, rendering their research significantly more challenging compared to that of C60 and C70.

Studies have demonstrated that the pronounced instability of C74 is attributable to its high electron affinity, the narrow energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) contributes to its kinetic instability. Consequently, the C74 isomer that satisfies the isolated pentagon rule (IPR) tends to undergo polymerization, rendering it insoluble in raw soot and challenging to extract using organic solvents. , Secondly, owing to its distinctive ellipsoidal structure, the carbon atoms on the surface of C74 exhibit an uneven electron distribution and elevated local strain. This results in higher chemical reactivity compared to C60 and C70, making it more susceptible to reactions with other molecules. This enhanced reactivity also contributes to the difficulty in maintaining its stable existence. Hollow C74 cages possess strong electron affinity and readily accept electrons from electron-rich donor species within extraction or chromatographic systems, the resulting C74 anions exhibit greatly improved structural stability compared with neutral empty C74. ,

Another strategy to substantially enhance the stability of the C74 carbon cage involves the encapsulation of metal atoms or metal clusters within its interior. Upon encapsulation of one or more electropositive metal species, such as Lanthanum (La), Praseodymium (Pr), Calcium (Ca), Barium (Ba), Europium (Eu), Uranium (U), Thorium (Th), or lutetium (Lu), into the fullerene framework, a profound electron transfer from the entrapped metal center(s) to the electron-avid carbon matrix is initiated. − This electron donation effectively satisfies the electron-deficient nature of C74, thereby conferring greatly improved intrinsic structural stability relative to the bare hollow C74 cage for the resulting endohedral metallofullerene structure. To date, the majority of well-characterized C74 derivatives exhibit D 3h symmetry and represent the only C74 isomers that satisfy the isolated pentagon rule, specifically those with the helical code 14246, denoted as D 3h (14246)-C74. ,

Trimetallic nitride-encapsulated fullerenes have garnered significant attention owing to their promising applications in biomedicine and single-molecule magnetism. − Recent theoretical advances have established the supplementary octet rule as a universal stability criterion for trinuclear μ3-bridged cluster fullerenes, which describes the valence octet requirement of central bridging light atoms for core stabilization, yet this framework has rarely been extended to nitride-type μ3-N clusters inside C74 cages. Nevertheless, there is no literature reporting the successful experimental isolation or spectroscopic characterization of pure Sc3N@C74 to date. Systematic gas-phase synthesis and mass spectrometry analysis of Sc-based nitride cluster fullerenes have proven that Sc3N@C80 is the dominant synthetic product, while Sc3N@C74 exhibits extremely low formation probability and cannot be detected under conventional laser plasma synthesis conditions. Noteworthy, previous investigations have explored C74-based endohedral metallofullerenes with different encapsulated clusters and atoms, such as monometallofullerenes Ba@C74 and oxide cluster fullerenes Tb2O@C74 systems, yet these systems carry distinct charge-transfer patterns and cluster-cage bonding modes compared with trimetallic nitride Sc3N@C74. , Unlike single metal atoms or Di-metal oxide cluster, the planar triangular Sc3N cluster transfers six valence electrons to the C74 cage and forms unique μ3-N-bridged intrametallic covalent bonds, which cannot be generalized from earlier mono/oxo-metallofullerene studies. This study aims to perform an in-depth analysis of the most stable configuration of Sc3N clusters encapsulated within the C74 cage using density functional theory (DFT). ,

2. Research Objectives and Significance

How the inner Sc3N cluster matches the outer C74 cage in both geometric shape and electronic characteristics is systematically clarified. Furthermore, charge transfer between the Sc3N unit and the C74 framework is investigated by analyzing electron transfer, charge distribution, and orbital interactions. This comprehensive electronic-level analysis provides insight into the underlying reasons for the enhanced stability of this endohedral metallofullerene structure. The HOMO–LUMO energy gap serves as a key descriptor for predicting the chemically reactive sites of molecules, offering a theoretical foundation for subsequent chemical modifications, including addition and redox reactions. The UV-vis-NIR spectrum for the most favorable isomer of Sc3N@D 3h (14246)-C74 was simulated at the same theoretical level via time-dependent density functional theory (TD-DFT) calculations. DFT calculations on Sc3N@C74 not only compensate for the limitations of experimental characterization in providing atomic-scale details but also provide deep insights into the underlying physical and chemical origins of its stability from a quantum chemical perspective, thereby establishing a critical link between molecular structure and functional properties. This offers essential theoretical support and predictive guidance for experimental efforts in synthesis, separation, functionalization, and further application-oriented studies. All DFT computations in this work were carried out with the Gaussian 16 program.

3. Results and Discussion

3.1. Structural Screening and Energy Optimization

It is well established that fullerenes adhering to the isolated pentagon rule exhibit superior thermodynamic stability. In contrast, non-IPR fullerenes, which contain adjacent pentagonal rings, experience significant ring strain and are consequently highly unstable. Nevertheless, a substantial number of studies have demonstrated that the encapsulation of metal clusters within non-IPR fullerenes markedly enhances the stability of these endohedral systems relative to their pristine, unoccupied counterparts-this stabilization arising predominantly from the interactions between the metal clusters and the carbon cages. − Therefore, the structural characteristics of non-IPR fullerenes warrant careful consideration.

A large number of experimental and theoretical computational studies indicate that the encapsulation of a trimetallic nitride leads to the transfer of six electrons to the carbon cage. − It is worth noting that the early systematic survey of nitride cluster fullerenes in ref only summarized general stability rules for a wide range of M3N@C2n fullerenes rather than focusing on C74-based systems. Compared with this preliminary research limited to rough energy tendency analysis, the present work achieves deeper, targeted characterization enabled by advanced computational frameworks, we completed full screening of 1943 C74 6– cage isomers, precisely optimized each Sc3N@C74 isomer with combined all-electron and effective core potential basis sets, and further supplemented quantitative bonding analysis via Mayer bond order and QTAIM theory, as well as TD-DFT optical spectrum simulation. Unlike the macroscopic trend description in ref , this work quantitatively uncovers the unique cluster-cage matching rule and mixed ionic–covalent stabilization origin of Sc3N@D 3h (14246)-C74, providing exclusive spectral fingerprints for subsequent experimental structural verification.

Accordingly, a preliminary energy screening of all C74 6– anionic isomers containing no more than three adjacent pentagons (a total of 1943 structures) was first carried out through the semiempirical AM1 method; the calculation results are listed in Table S1 of the Supporting Information. Subsequently, 55 C74 6– anion models with relative energies not exceeding 50.0 kcal·mol–1 were selected and further optimized using the hybrid density functional B3LYP method; 6–31G basis set was uniformly employed across all carbon atoms, ensuring consistency and reliability in the computational framework; − the calculation results are presented in Table . The isomer with the lowest relative energy is the C74-C 2-13295 carbon cage, which incorporates two PA fragments; the second-lowest-energy isomer is C74-C 2-13333, lying 5.0 kcal·mol–1 higher in energy. Intriguingly, the only C74 empty-cage isomer that satisfies the isolated pentagon rule, C74-D 3h -14246, exhibits the third-lowest relative energy at 6.2 kcal·mol–1 above the most stable structure.

1. Relative Energies (kcal·mol–1) of C74 6– Isomers Calculated at B3LYP/6-31G Method.

spiral ID Sym. PA ΔE
C74-C 2-13295 C 2 2 0.0
C74-C 2-13333 C 2 2 5.0
C74-D 3h -14246 D 3h 0 6.2
C74-C 1-13408 C 1 2 9.0
C74-C 2-13290 C 2 2 10.1
C74-C 2-13291 C 2 2 14.6
C74-C 3-13492 C 3 3 17.8
C74-C 1-13391 C 1 2 18.6
C74-C 2-13292 C 2 2 18.7
C74-C 2v -14239 C 2v 2 22.6
C74-C 1-13384 C 1 2 23.9
C74-C 1-13479 C 1 3 25.2
C74-C s -13336 C s 2 25.3
C74-C 1-13771 C 1 2 25.7
C74-C 2-13961 C 2 2 26.9
C74-C 1-13549 C 1 2 28.2
C74-C 1-13410 C 1 2 28.7
C74-C 1-13334 C 1 2 30.5
C74-C 1-13321 C 1 3 31.4
C74-C 1-13356 C 1 3 31.6
C74-C 1-13393 C 1 1 32.2
C74-C 1-14049 C 1 1 32.2
C74-C 2-13780 C 2 3 32.3
C74-C 1-13825 C 1 2 33.7
C74-C 1-13510 C 1 2 33.9
C74-C 1-13335 C 1 2 34.1
C74-C 2v -13293 C 2v 2 34.5
C74-C 1-13386 C 1 2 37.7
C74-C 2-14035 C 2 2 38.0
C74-C 1-13787 C 1 2 42.6
C74-C 2-14227 C 2 1 42.8
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a

Symmetry of the original hollow cages.

b

Number of pentagon adjacencies.

Then, the aforementioned optimally configured empty cages and identified negatively charged ion models exhibiting relative potential energies below 25 kcal·mol–1 were selected as candidate structures for constructing models of Sc3N cluster encapsulated within carbon cages. In the calculation, geometry optimization was performed at the B3LYP/6-31G­(d)∼CEP-31G theoretical level, in the simulation, the 6–31G­(d) basis set is applied for C and N atoms, whereas the CEP-31G effective core potential basis set is employed for the metal atoms, this combination of basis sets ensures both computational accuracy and efficiency. , Meanwhile, during the optimization process, the distinct positional distributions of the Sc3N clusters within the C74 carbon cage were considered to identify the most stable configuration for each isomer. The energy optimization results for the most stable configuration of each endohedral structure are presented in Table . Significantly, it can be concluded that the lowest-energy isomer following the encapsulation of the Sc3N cluster is Sc3N@D 3h (14246)-C74. However, as shown in Table , the D 3h (14246)-C74 cage is not the most stable isomer in the absence of the cluster, the most stable isomer of the empty C74 cage, C74-C 2-13295, lies 11.6 kcal·mol–1 higher in energy than the most stable endohedral structure, Sc3N@D 3h (14246)-C74, after Sc3N incorporation, it becomes evident from this observation that the encapsulated metal clusters directly modulate the stability of the fullerene carbon cage. Frequency analysis was performed at the same computational level based on the optimized structures to confirm that all the obtained stationary points are true energy minima. Upon reviewing the literature, it was observed that when isolated metal atoms, such as La and Th, as well as bimetallic carbenes like Sc2C2, and trimetallic clusters such as Er3, are encapsulated within the C74 fullerene framework, the most thermodynamically stable isomers consistently adopt the D 3h (14246)-C74 configuration; this indicates that the D 3h (14246)-C74 carbon cage shows a distinct advantage in encapsulating metal atoms and clusters. ,− To further validate the reliability of our isomer energy ordering, we reoptimized all candidate Sc3N@C74 structures at the ωB97XD/6-31G­(d)∼CEP-31G level with identical basis set settings. The relative energies calculated from this dispersion-corrected functional reproduce the same stability sequence as the B3LYP results, and Sc3N@D 3h (14246)-C74 is consistently identified as the global energy minimum. Detailed relative energy and HOMO–LUMO gap data from ωB97XD calculations are tabulated in Table S2 of the Supporting Information. Notably, Dunsch et al. previously suggested Sc3N@C2(13295)-C74 as the most stable isomer, which conflicts with our identification of Sc3N@D 3h (14246)-C74 as the global energy minimum. This inconsistency mainly arises from its incomplete cage screening and lack of systematic scanning for multiple internal orientations of the Sc3N cluster. In contrast, we exhaustively screened all 1943 C74 6– cage candidates, optimized diverse cluster positions for every cage, and cross-verified all energy sequences using both B3LYP and ωB97X-D functionals with vibrational frequency validation. Such multistep verification makes our isomer stability ordering more comprehensive and reliable than the limited preliminary calculations in ref .

2. Relative Energies (kcal·mol–1) and HOMO–LUMO Gaps (eV) of Sc3N@C74 Isomers Calculated at B3LYP/6-31G­(d)∼CEP-31G.

spiral ID Sym. PA ΔE Gap
14246 D 3h 0 0.0 1.51
13333 C 2 2 8.2 1.51
14239 C 2v 2 10.6 1.57
13295 C 2 2 11.6 1.92
13492 C 3 3 13.0 1.99
13408 C 1 2 14.5 2.12
13290 C 2 2 19.2 1.57
13291 C 2 2 20.6 1.70
13391 C 1 2 22.0 1.59
13292 C 2 2 22.5 1.69
13384 C 1 2 29.1 1.13
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a

Symmetry of the original hollow cages.

b

Number of pentagon adjacencies.

3.2. Geometric Structure Analysis

The structure of the most stable endohedral fullerene, Sc3N@D 3h (14246)-C74, is illustrated in Figure . As shown in Figure , the Sc–N bond length (∼2.02 Å) and the Sc–N–Sc bond angles (∼117–121°) of Sc3N@D 3h (14246)-C74 in this study indicate a certain degree of distortion in the encapsulated cluster. In contrast, the Sc–N bond lengths in Sc3N@C 2v (7854)-C70 reported in previous studies are 2.039, 2.045, and 1.976 Å, and the Sc–N–Sc angles are 105.1°, 104.8°, and 150.1°. Meanwhile, Sc3N@C 2v (39718)-C82 exhibits a longer bond length (2.07 Å) and more extreme bond angles (95.23° and 132.13°), suggesting that the geometry of the carbon cage exerts markedly different constraints on the internal cluster. In summary, the embedded Sc3N clusters within a series of fullerene carbon cages exhibit systematic structural responses: first, the Sc–N bond length displays a pronounced size-dependent trend, increasing with the expansion of the carbon cage, which is primarily attributed to the combined influence of spatial confinement and intrinsic electronic effects within the cage, second, the clusters undergo adaptive deformation via modulation of the Sc–N–Sc bond angle to accommodate the distinct geometries and local environments (such as pentagon-adjacent fragments) of different carbon cages. In the carbon cages of C 2v (7854)-C70 and C 2v (39718)-C82, which exhibit relatively lower symmetry, the distribution of pentagon-adjacent (PA) fragments induces an asymmetric distortion of the Sc–N–Sc bond angles. In contrast, the D 3h (14246)-C74 carbon cage, characterized by high D 3h symmetry and compliance with the isolated pentagon rule (IPR), provides a highly uniform confinement environment for the encapsulated cluster, resulting in a more homogeneous distribution of the Sc–N–Sc bond angles.

1.

1

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Structure of Sc3N@D 3h (14246)-C74.

3.3. Electronic Property Analysis

It is well established that the macroscopic properties, such as stability, distinctive electronic spectral features, and chemical reactivity, arise fundamentally from intricate electronic interactions between the carbon cage and the encapsulated cluster. A deeper understanding of these interactions is urgently required, particularly regarding the degree of charge transfer, the composition and energy-level distribution of frontier molecular orbitals, and the covalent character of metal-cage bonding, all of which must be elucidated from a more comprehensive electronic structure perspective. A systematic molecular orbital theory analysis of this system is performed to elucidate the extent and pathway of charge transfer from Sc3N clusters to the C74 carbon cages. This is achieved by examining the spatial distribution, energy level differences, and composition of the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO), thereby clarifying their redox relationship. Furthermore, the characteristics of bonding orbitals between the metal atoms and the carbon cage are investigated through Mayer bond order (MBO) and bonding critical point (BCP) based on the quantum theory of atoms in molecules analysis, providing insights into the strength and nature of the chemical bonds involved in the cluster–cage interaction. MBO and BCP analyses were provided by MULTIWFN 3.2 program.

As shown in Table , the LUMO–HOMO energy gap of Sc3N@D 3h (14246)-C74 is 1.51 eV, suggesting enhanced kinetic stability and favorable synthetic accessibility under laboratory conditions. Figure presents the LUMO and HOMO orbital distribution diagrams of Sc3N@D 3h (14246)-C74. As shown, the electron density in both the LUMO and HOMO is predominantly localized on the C74 carbon cage, suggesting that any subsequent redox processes will occur preferentially on the cage surface rather than on the encapsulated Sc3N cluster. Nevertheless, the analysis reveals a non-negligible degree of orbital overlap between Sc3N and the C74 cage, indicating that Sc3N does not fully transfer six electrons to the carbon framework. Thus, the interaction between Sc3N and C74 involves not only ionic character but also a significant covalent contribution.

2.

2

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HOMO and LUMO orbitals of Sc3N@D 3h (14246)-C74.

To gain deeper insight into the covalent bonding interactions-specifically between the metal and nitrogen atoms, as well as between the metal atoms and the carbon cage-in Sc3N@C74, a comprehensive Mayer bond order (MBO) and BCP analysis was performed on the most stable isomer, Sc3N@D 3h (14246)-C74, the results are summarized in Table . The analysis reveals that the MBO values between Sc and N atoms range from 0.78 to 0.89, indicating predominantly covalent single-bond character in the Sc3N interactions, this insight provides valuable clues for understanding the structural stability of this isomer. Secondly, the MBO values between the Sc atom and adjacent carbon atoms on the carbon cage range from 0.25 to 0.27, and the electron density (ρBCP) and Laplacian of electron density (▽2ρBCP) are small and positive, the total energy density (H BCP) is negative, and the ratio of the kinetic energy density GBCP to ρBCP is close to 1 between inner metal atoms and carbon cages, indicating not only significant ionic interactions but also a non-negligible, chemically meaningful covalent contribution to the metal-cage bonding. Evidently, this “internal covalent, external covalent” bonding paradigmcharacterized by the synergistic stabilization arising from strong internal covalent bonds within the Sc3N cluster and external covalent bonds between the metal nitride core and the C74 cageconstitutes a key electronic-structure foundation for the exceptional thermodynamic stability of the Sc3N@C74 isomer. The QTAIM topological indicators and Mayer bond order results obtained herein corroborate the widely accepted mixed ionic–covalent bonding nature of metal-cage interactions in endohedral metallofullerenes established in previous systematic QTAIM investigations and comprehensive review literature. ,

3. Mayer Bond Order (MBO) and Bonding Critical Point (BCP) Analyses of Sc3N@D 3h (14246)-C74 .

    d (Å) MBO ρBCP (a.u.) ▽ 2ρBCP (a.u.) H BCP (a.u.) |V BCP|/G BCP G BCP/ρBCP
Sc77 C18 2.28 0.26 0.057 0.209 –0.005 1.086 1.017
  C65 2.28 0.26 0.057 0.210 –0.005 1.089 1.014
  N78 2.02 0.78 0.096 0.393 –0.019 1.159 1.213
Sc75 C57 2.31 0.27 0.054 0.196 –0.004 1.075 0.981
  C58 2.32 0.25 0.052 0.196 –0.003 1.077 1.008
  N78 2.01 0.89 0.098 0.397 –0.020 1.168 1.214
Sc76 C48 2.34 0.25 0.052 0.195 –0.003 1.058 1.006
  C49 2.31 0.27 0.054 0.197 –0.004 1.079 0.991
  N78 2.01 0.89 0.098 0.396 –0.020 1.160 1.208
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Notably, Sc3N@D 3h (14246)-C74 has not yet been isolated experimentally, unlike many well-characterized Sc3N@C2n cluster fullerenes. According to our computational results, this phenomenon cannot be attributed to insufficient intrinsic molecular stability of Sc3N@C74 itself. Instead, three critical experimental constraints account for its non-detection: Sc3N clusters tend to form more favorable large-cage nitride fullerenes such as Sc3N@C80 during synthesis; the D 3h (14246)-C74 cage precursor exists in tiny amounts in raw soot, and its moderate HOMO–LUMO gap brings relatively high kinetic reactivity, making crude Sc3N@C74 prone to side reactions. Studies have demonstrated that isomers with the same molecular formula but different structures often exhibit significantly different UV-vis-NIR absorption spectral characteristics and can be distinguished by multiple well-resolved characteristic absorption peaks. Accordingly, we performed density functional theory (DFT)-based simulations to compute the UV-vis-NIR absorption spectrum of the thermodynamically most stable isomer Sc3N@D 3h (14246)-C74 in this system (Figure ), thereby providing a quantitative and experimentally verifiable theoretical foundation for its synthesis and spectroscopic characterization in subsequent experiments. The absorption spectrum of Sc3N@D 3h (14246)-C74 could be divided into three major regions, containing several strong absorption peaks at 368–485 nm, where two strong sharp peaks are discovered at 636 and 681 nm, followed by three iso-intensity and moderate absorption peaks (872, 942, and 1045 nm) at the range of 850–1100 nm. These predicted unique fingerprint absorption bands serve as quantitative spectral fingerprints, which can offer solid auxiliary evidence to unambiguously distinguish the target Sc3N@D 3h (14246)-C74 isomer from other cage isomers and support structural determination in follow-up experimental synthesis and characterization.

3.

3

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Simulated UV-vis-NIR spectra of Sc3N@D 3h (14246)-C74.

4. Conclusion

This study systematically investigates the stability and electronic structures of the Sc3N@C74 endohedral metallofullerene using density functional theory. Results indicate that the D 3h (14246)-C74 carbon cage complying strictly with the isolated pentagon rule exhibits the lowest total energy upon encapsulation of the Sc3N cluster, thereby identifying it as the thermodynamically most stable isomer of Sc3N@C74. Geometric analysis reveals that the encapsulated Sc3N cluster retains an approximately planar triangular configuration inside the cage, moreover, the Sc–C distances between each scandium atom and its nearest cage carbon atoms vary systematically with local carbon-cage curvature. Frontier molecular orbital analysis demonstrates substantial electron transfer from the Sc3N cluster to the C74 cage, accompanied by pronounced orbital hybridization between Sc 3d/4s and π orbitals of cage. Mayer bond order and bonding critical point based on the quantum theory of atoms in molecules analysis quantitatively confirm a non-negligible covalent contribution to the Sc–C interactions, beyond purely electrostatic stabilization, thereby establishing a mixed ionic–covalent bonding character. This covalent Sc–C interaction, together with the strong internal Sc–N covalent bonds, forms the essential chemical basis for the structural stabilization of the endohedral system. In summary, this work comprehensively elucidates the structural features and stabilization mechanism of the most stable Sc3N@C74 isomer through integrated analyses of energetics, geometries, electronic structures, and chemical bonding properties, providing a robust theoretical foundation for understanding the stability principles governing metal nitride endohedral fullerenes.

Supplementary Material

ao6c06001_si_001.pdf (111.5KB, pdf)

Acknowledgments

This work has been supported by the Natural Science Foundation of Shanxi Province of China (No. 202503021212234), the Science and Technology Innovation Project of Higher Education Institutions in Shanxi Province (No. 2023L264), and the Datong Applied Basic Research Project Fund (No.2025079).

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.6c06001.

  • DFT optimization of C74 6– anions at B3LYP/6-31G; Cartesian coordinates of Sc3N@D 3h (14246)-C74 (PDF)

The authors declare no competing financial interest.

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