Missing Metallofullerene La@C₇₄

Abstract

The first isolation of missing metallofullerene, La@C74, as a derivative is reported. The structural determination has been performed by spectroscopic and, finally, X-ray crystallographic analysis, and the properties of La@C74 are discussed on the basis of the theoretical study.

Computations on three isomers of La@C74

“…In the temperature region around 1,500 K, the 1/D 3h species is clearly prevailing while the two non-IPR cagerelated isomers 103/C 1 and 4/C 1 represent just a few percent of the equilibrium isomeric mixture. The proportions are in agreement with the observation [10] in which just one La@C 74 species was isolated and evidenced by X-ray analysis to contain the IPR carbon cage. According to the calculations, the La endohedrals with non-IPR C 74 cages could possibly be isolated only with a great effort.…”

“…W hile empty C 74 fullerene [1] has still not been available, various related C 74 -based metallo-fullerenes have been known and studied vigorously like Ca@C 74 [2,3], Sm@C 74 [4,5], Sr@C 74 [6], Ba@C 74 [7], La@C 74 [8][9][10], Eu@C 74 [11], Yb@C 74 [12][13][14], Sc 2 @C 74 [15], or Er 3 @C 74 [16]. Among them, La@C 74 has a special position as its X-ray crystallographic analysis is available [10], although for a solventrelated derivative, La@C 74 -C 6 H 3 Cl 2 .…”

“…Among them, La@C 74 has a special position as its X-ray crystallographic analysis is available [10], although for a solventrelated derivative, La@C 74 -C 6 H 3 Cl 2 . The computations [10] demonstrated that in La@C 74 the spin density is rather concentrated on a few atoms, in contrast to those in La@C 82 , with an even distribution, and this high radical character of the cage explains the higher reactivity of La@C 74 . Another interesting case is Yb@C 74 , where even two isomers were isolated [12].…”

“…This paper deals with calculations of La@C 74 again from the point of view of possibilities for encapsulation into non-IPR C 74 cages, consistently using the Gibbs energies as required by high temperatures [27,28]. These computations should further enhance knowledge of the La@C 74 features accessible from calculations only [10,29,30]. …”

Crystal Structures of Saturn‐Like C50Cl10 and Pineapple‐Shaped C64Cl4: Geometric Implications of Double‐ and Triple‐Pentagon‐Fused Chlorofullerenes

“…[6][7][8] Detailed information regarding their geometries and intermolecular interactions, however, requires single-crystal X-ray characterization, as in the case of Sc 3 N@C 68 . [9] The crystal structures of two double-fused-pentagon endohedral metallofullerenes, namely La@C 72 (C 6 H 3 Cl 2 ) [10] and Tb 3 N@C 84 , [11] have also been determined. Highly accurate structural parameters established by X-ray crystallography are rare for exohedral derivatives of IPR-violating fullerenes.…”