Properties of the Only Thorium Fullerene, Th@C₈₄, Uncovered

Abstract

Only a single thorium fullerene, Th@C, has been reported to date (Akiyama, K.; et al. J. Nucl. Radiochem. Sci. 2002, 3, 151-154). Although the system was characterized by UV-vis and XANES (X-ray absorption near edge structure) spectra, its structure and properties remain unknown. In this work we used the density functional calculations to identify molecular and electronic structure of the Th@C. Series of molecular structures satisfying the ThC stoichiometric formula were studied comprising 24 IPR and 110 non-IPR Th@C isomers as well as 9 ThC@C IPR isomers. The lowest energy structure is Th@C-C(10) with the singlet ground state. Its predicted electronic absorption spectra are in agreement with the experimentally observed ones. The bonding between the cage and Th was characterized as polar covalent with Th in formal oxidation state IV. The NMR chemical shifts of Th@C-C(10) were predicted to guide the future experimental efforts in identification of this compound.

Robust metal‐pentagon interactions in the Th‐based endohedral metallofullerenes revealed by DFT calculations

“…Note that, although holding a formal 4+ oxidation state, the thorium cation resides close to only three pentagons of the C 3v (8)‐C 82 cage, whereas four pentagons are indispensable for thorium(IV) coordination in typical organometallic complexes such as Th( η 5 ‐C 5 H 5 ) 4 . According to the mass spectra signals of Th@C 2 n (2 n = 74‐96) reported by Chen and coworkers, the possible structures of Th@D 3h (1)‐C 74 , Th@T d (2)‐C 76 , and Th@C s (10)‐C 84 are quickly proposed by our and other's theoretical calculations . Interestingly, we found that the Th atom in Th@D 3h (1)‐C 74 may undergo an unprecedented three‐dimensional motion in the cage .…”

“…[23] According to the mass spectra signals of Th@C 2n (2n = 74-96) reported by Chen and coworkers, the possible structures of Th@D 3h (1)-C 74 , Th@T d (2)-C 76 , and Th@C s (10)-C 84 are quickly proposed by our and other's theoretical calculations. [13,[24][25][26] Interestingly, we found that the Th atom in Th@D 3h (1)-C 74 may undergo an unprecedented three-dimensional motion in the cage. [13] Besides the Th-EMFs, Echegoyen and coworkers recently obtained three uranium metallofullerenes U@D 3h (1)-C 74 , U@C 2 (5)-C 82 , and U@C 2v (9)-C 82 .…”

Th@C76. Computational characterization of larger actinide endohedral fullerenes

“…[14] More actinide EMFs are only predicted by the theoretical calculations. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] In particular, computational studies have disclosed the exceptional structural and bonding natures of uranium EMFs. [30][31][32][33][34][35] Significantly, Wang et al more recently prepared a large family of Th@C 2n (2n 5 74-96) by a modified arc discharge method, and for the first time, they successfully isolated Th@C 82 and unambiguously characterized its structure as Th@C 3v (8)-C 82 by X-ray crystallographic analysis.…”

“…Moreover, most of them are focused on the uranium‐containing ones as exemplified by the more recent successful synthesis and X‐ray characterization of U@D 3h ‐C 74 , U@C 2 (5)‐C 82 , and U@C 2v (9)‐C 82 . More actinide EMFs are only predicted by the theoretical calculations . In particular, computational studies have disclosed the exceptional structural and bonding natures of uranium EMFs …”

New theoretical insights into high-coordination-number complexes in actinides-centered borane

“…2 The carbon fullerene and its analog have been also projected to achieve high CN, such as observed M@C60 or M@(BN)n where the metal atom directly interacts with part of cluster in those cases, [3][4][5] with similarity to Th@C84 or U@C36. [6][7][8] In addition, theoretically authenticated molecular metal-fullerenes have widespread across the group 14 clusters, [9][10][11][12][13] mainly focusing on the stability of the fullerene structures, where these fullerenes provide electrostatic field that the metal atom in those cases interacts with the fullerenes shell primarily ionically. 14 And the record of high coordination complexes involving the metal elements has been updated from 14 in U(BH4)4, 15 then to 15 in [Th(H3BNMe2BH3)4] by Daly et al, 16 and recently to 16 in CoB16 by Popov et al.…”