Nitrides endohedral fullerenes

Ge Z, Duchamp JC, Cai T, Gibson HW, Dorn HC (2005) Purification of endohedral trimetallic nitride fullerenes in a single, facile step. J. Am. Chem. Soc. 127 16292-16298. 

Chaur MN, Athans AJ, Echegoyen L (2008) Metallic nitride endohedral fullerenes synthesis and electrochemical properties. Tetrahedron 64 11387-11393... 

Up to 1999, only metal atoms [1-5], metal clusters [6,7], metal nitrides [55-57], and noble gas atoms [58-60] were observed to be encaged inside C60, C70, or various sizes of higher fullerenes. The experimental evidence for carbon atoms or metal-carbon compounds (carbides) being encapsulated inside fullerenes had not yet been observed. In 2000, Shinohara et al. succeeded in the first production, isolation, and spectroscopic characterization of a scandium carbide endohedral fullerene (Sc2C2) C84. Following this, the first experimental evidence based on synchrotron X-ray diffraction was presented and revealed that the Sc carbide is encapsulated in the form of a lozenge-shaped Sc2C2 cluster inside the D2d-C84 fullerene [8]. 

Endohedral Fullerenes Containing Metal Nitride Units. 222... 

The first endohedral fullerenes to be studied in detail are the monometallofullerenes, with the general formula M C . Until the recent synthetic breakthroughs as regards the trimetal nitride endohedrals [6].monometallofullerenes of the rare-earth metals such as M C82 were the most abundant endohedral fullerenes and have been the subject of numerous investigations world-wide. 

To close this section on trimetal nitride endohedral fullerenes, we present and discuss data from potassium intercalation experiments on Sc3N C80. As was the case for Kx(Tm C82), x-ray photoemission measurements of the K 2p and C Is signals can be used to give a good indication of the overall potassium concentration in such intercalation compounds. Figure 16 displays the K 2p photoemission lines for several intercalation levels in Kx(Sc3N C80). 

Zuo, T.M., Olmstead, M.M., Beavers, C.M. etal. (2008) Preparation and structural characterization of the 7h and the Dsh isomers of the endohedral fullerenes TmsNOCgo icosahedral Cgo cage encapsulation of a trimetallic nitride magnetic cluster with three uncoupled Tm + ions. Inorganic Chemistry, 47, 5234-5244. 

The major products formed by DC arc discharge are empty fullerenes, with the endohedral fullerenes composing only about 1% of the raw soot. For this reason, better extraction methods are always being sought. Sublimation is a fairly efficient metiiod for extraction and is a solventless technique. Nevertheless, file most popular method for extraction of endohedral fiiUerenes is solvent extraction. Some popular solvents for extraction are xylene, carbon disulfide, and toluene. The efficiency of this method is not great because about half of the endohedral fiillerenes remain in the extracted residue, which needs further processing with other solvents. Extraction of trimetallic nitride endohedral fiillerenes has a higher efficiency because of increased solubility in common solvents. 

FIGURE 11 An endohedral scandium nitride fullerene cluster (25). 

Chaur, M. N., Valencia, R., Rodriguez-Fortea, A., Poblet, J. M., Echegoyen, L. (2009a). Trimetal-lic nitride endohedral fullerenes Experimental and theoretical evidence for the M3N C2n model. Angewandte Chemie, International Edition, 48,1425-1428. 

The electrochemical properties of TNT-EMFs, M3N C2n n > 39) differ from those of the empty cage fullerenes (see Fig. 6) due to the interaction of the metal cluster with the carbon cage and because the structure of these carbon cages are generally different. As a consequence, the reductive processes are electrochemically irreversible but chemically reversible. The oxidative processes occur at lower potentials because the HOMO orbital is mainly localized on the trimetallic nitride clusters and the HOMO-LUMO gaps in solution are smaller [25,58]. The endohedral metallo-fullerenes M C2n show similar behavior but even smaller HOMO-LUMO gaps [59]. 

Dunsch L, Krause M, Noack J et al (2004) Endohedral nitride cluster fullerenes. Formation and spectroscopic analysis of L3 xMxN C2n (0 < x < 3 N = 39,40). J Phys Chem Solids 65 309-315... 

Cardona, C.M., Kitaygorodskiy, A., and Echegoyen, L. (2005) Trimetallic nitride endohedral metallo-fullerenes reactivity dictated by the encapsulated metal cluster. Journal of the American Chemical Society, 127, 10448-10453. 

Abstract We report here a review of our recent efforts at understanding and predicting reactivity and regioselectivity of endohedral (metallo)fullerenes and their parent free fullerenes. The effect of encapsulation of trimetallic nitrides or noble gas atoms/dimers was shown to have a profound impact on the stability and reactivity of fullerene compounds. It is not just the encapsulation, but in particular the nature of the species that is encapsulated that determines how (un)reactive the fullerene becomes. These findings have important consequences for future applications of (metallo)fullerenes in biomedicine and (nano)technology. 

Trimetallic nitride endohedral fiiUerenes have been sought for use in MRl contrast agent ( Lanthanides Magnetic Resonance Imaging) and optoelectronic devices because of the wide variety of trimetallic nitride clusters that can be encapsulated in the fullerene, which can be used to tune properties of the material. ... 

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