Ever since the first experimental evidence of the existence of endohedral metallofullerenes (EMFs) was obtained, the search for carbon cages with encapsulated metals and small molecules has become a very active field of research. EMFs exhibit unique electronic and structural features, with potential applications in many fields. Furthermore, functionalized EMFs offer additional potential applications because of their higher solubility and their ease of characterization by X-ray crystallography and other techniques. Herein we review the general field of EMFs, particularly of functionalized EMFs. We also address their structures and their (electrochemical) properties, as well as applications of these fascinating compounds.

Chemical, electrochemical, and structural properties of endohedral metallofullerenes.

Structural aspects of fullerene chemistry--a journey through fullerene chirality.

The world of endohedral fullerenes was significantly enlarged over the past seven years by the cluster fullerenes, which contain structures such as the M(2)C(2) carbides and the M(3)N nitrides. While the carbide clusters are generated under the standard arc-burning conditions according to stabilization conditions, the nitride cluster fullerenes (NCFs) are formed by varying the composition of the cooling gas atmosphere in the arc-burning process. The special conditions for NCF synthesis is described in detail and the optimum conditions for the production of NCFs as the main product in fullerene syntheses are given. A general review of all NCFs reported to date consists of the structures, properties, and stability of the NCFs as well as the abundance of the NCFs in the fullerene soot. It is shown that all cages with even carbon atoms from C(68) to C(98) are available as endohedral nitride cluster structures (with the exception of C(72), C(74), and C(76)). Specifically, the NCFs form the largest number of structures that violate the isolated pentagon rule (IPR). Finally some practical applications of these cluster fullerenes are illustrated and an outlook is given, taking the superior stability of these endohedral fullerenes into account.

Metal nitride cluster fullerenes: their current state and future prospects.

Carbon Nanotubes and Related Structures

New challenges in fullerene chemistry.

The first pyrrolidine adduct on Sc3N@C80 was synthesized and fully characterized. Addition of the N-ethylazomethine ylide occurs regioselectively on a [5,6] double bond on the surface of the icosahedral symmetry Sc3N@C80, exactly in the same position as that described previously for a Diels−Alder adduct of the same compound.11a,b This addition pattern results in symmetric pyrrolidine carbons and unsymmetric geminal hydrogens on the pyrrolidine ring, as confirmed by 1H and 13C NMR spectroscopy, especially by HMQC. The shielding environment experienced by these geminal hydrogens differs by 1.26 ppm, indicative of pronounced ring current effects on the surface of this endohedral fullerene. This represents the first fully characterized pyrrolidine adduct on an endohedral metallofullerene.

The First Fulleropyrrolidine Derivative of Sc3N@C80: Pronounced Chemical Shift Differences of the Geminal Protons on the Pyrrolidine Ring

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and M. Ángeles Herranz

Papers

The First Fulleropyrrolidine Derivative of Sc3N@C80: Pronounced Chemical Shift Differences of the Geminal Protons on the Pyrrolidine Ring

The First Fulleropyrrolidine Derivative of Sc3N@C80: Pronounced Chemical Shift Differences of the Geminal Protons on the Pyrrolidine Ring.