Electronic structure calculation of vanadium‐and scandium‐based endohedral fullerenes VSc₂N@C_2n (2n = 70, 76, 78, 80)

Abstract

We present candidate structures for the most stable isomers for the VSc 2 N@C 70 , VSc 2 N@C 76 , VSc 2 N@C 78 , and VSc 2 N@C 80 using a systematic procedure that involves all possible isomers of the host fullerene cages. Subsequently, a detailed investigation of structural and electronic properties of the lowest energy isomers is performed using density functional theory in combination with large polarized Gaussian basis sets. The search correctly identifies the experimentally observed VSc 2 N@C 80 isomer as the most stable structure. The structural analysis shows that only VSc 2 N@C 70 has a non-IPR cage among the four endohedral fullerenes. Respectively, VSc 2 N@C 70 and VSc 2 N@C 76 have nearly degenerate spin states with total spin S = 0 and S = 1.All the lowest energy cages are energetically stable and show significant electron accepting capacity comparable to C 60 .degenerate spin states, quasiparticle gap, magnetic spin moment 1 | INTRODUCTION Carbon cages in endohedral fullerenes serve as a robust container to accommodate some units like atoms, molecules, and clusters. Just after the discovery of Buckminsterfullerene C 60 in 1985 by Smalley and coworkers, [1] the endohedral fullerene La@C 60 was synthesized for the first time in the same year. [2] The attention on endohedral fullerenes grew after its macroscopic production by Huffman and his group in 1990. [3] Still, the production of endohedral fullerenes was low and was about only 1% of the total production of empty fullerene cages. Harry Dorn and coworkers in 1999 successfully synthesized tri-scandium nitride cluster fullerene Sc 3 N@C 80 using N 2 gas environment in the Krätschmer-Huffman arc generator, which greatly enhances the yield of endohedral fullerenes. [4] The higher kinetic stability obtained from the gap opening between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) makes this nitride cluster fullerene (NCF) the most abundant fullerene after C 60 and C 70 . Subsequently, other synthesis methods for endohedral fullerenes were reported, which produced endohedral fullerenes in macroscopic amounts. [5][6][7][8][9] Attractive properties like large surface areas, high electron accepting capacity, and empty space to accommodate atoms, molecules, and cluster for potential use in different applications such as medicine and electronics make the fullerenes and endohedral fullerenes one of the active areas of research. [10][11][12][13][14][15][16][17][18][19][20] The stability of fullerenes is driven by the isolated pentagon rule (IPR). This rule is strictly followed by empty cage fullerenes, and it grants stability to only those fullerenes in which all the pentagonal sides are shared by hexagons. It has been pointed out that it is not possible for the C 20 -C 58 , C 62 -C 68 cages to satisfy the isolated pentagon rule. These carbon cages have high strain, and as a result, are unstable and difficult to isolate.In the endohedral form, however, the complexation releases large strain energy, which leads to f...

Stability and Electronic Properties of Mixed Rare-Earth Tri-Metallofullerenes YxDy3-x@C80 (x = 1 or 2)

“…Consequently, the stability of YDy 2 @C + 80 can be elucidated in a manner similar to that of Y 2 Dy@C + The magnetic characteristics of rare-earth metallofullerenes are intriguing. Some of them are formed in high spin states [56,57]. There have been reports highlighting the single-molecule magnet behavior of the clusterfullerenes Y 2 DyN@C 80 and YDy 2 N@C 80 [58].…”