Endohedral fullerenes: the importance of electronic, size and shape complementarity between the carbon cages and the corresponding encapsulated clusters

Abstract

Cage‐cluster complementarity is of crucial importance in determining the sizes and structures, as well as the properties of endohedral fullerenes. The encapsulated atoms or clusters, which are typically in a positively charged state, are irreversibly, mechanically, and electrostatically trapped inside the typically negatively charged cages. These rather exotic compounds exhibit exquisitely complementary properties between their components. Here, we present a short overview to show that size and shape are crucial in determining the specific structures that are formed, and the presence of electrostatic interactions result in structural motifs that are never observed for pristine fullerene cages. Copyright © 2014 John Wiley & Sons, Ltd.

Graph Theory of Aromatic Stabilization

“…However, one must remember that pentalene units are often adopted by the cages of many endohedral metallofullerenes. 155 In these carbon cages, pentalene units are no longer an effective destabilizing factor for the carbon cage.…”

Cluster-size dependent internal dynamics and magnetic anisotropy of Ho ions in HoM2N@C80and Ho2MN@C80families (M = Sc, Lu, Y)

“…21 Therefore, encapsulation of ions of different size within the same carbon cage alters internal geometrical parameters of the cluster such as metal-nitrogen distances. [22][23][24][25] In due turn, geometrical changes can be used to tune the physicochemical properties of encapsulated ions.…”

Kinetic Stability of Non-IPR Fullerene Molecular Ions

“…76 It seems that large non-IPR fullerenes are rather reluctant to form metallofullerenes. 22 Molecular structures of La 2 @D 5 (IPR-450)-C 100 77 and Sm 2 @D 3d (IPR-822)-C 104 76 allow us to evaluate whether the choice of a cage isomer in a large endohedral fullerene is still determined by the stability of the empty anionic cage. 38 In these metallofullerenes, C 100 and C 104 bear formal charges of -6 and -4, respectively.…”

“…16,17 Many non-IPR fullerenes have been isolated and characterized in the form of metallofullerenes. [18][19][20][21][22][23] Kinetic stability of metallofullerenes could be predicted from the min BRE for the negatively charged carbon cage. [24][25][26][27] We reported that carbon cages in all IPR and some non-IPR metallofullerenes so far isolated are kinetically stable with min BREs > -0.100 |β|.…”

“…An X-ray single crystal structure may be required to solve these conflicting observations. 22 C 2v (6073)-C 68 is used as a carbon cage in Sc 2 S@C 68 , in which C 68 behaves as a molecular tetraanion. 64 For the convenience of future study, both candidate fullerenes C 2v (7854)-C 70 and C 2v (6073)-C 68 are entered in Tables 1-3.…”