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Under photoirradiation, Sc3N@Ih-C80 reacted readily with disilirane 1, silirane 4, and digermirane 7 to afford the corresponding 1:1 adducts, whereas Sc3N@D5h-C80 was recovered without producing those adducts. Based on these results, we described a novel method for the exclusive separation of Ih and D5h isomers of Sc3N@C80. The method includes three procedures: selective derivatization of Sc3N@Ih-C80 using 1, 4, and 7, facile HPLC separation of pristine Sc3N@D5h-C80 and Sc3N@Ih-C80 derivatives, and thermolysis of Sc3N@Ih-C80 derivatives to collect pristine Sc3N@Ih-C80. In addition, laser flash photolysis experiments were conducted to elucidate the reaction mechanism. Decay of the transient absorption of 3Sc3N@Ih-C80 * was observed to be enhanced in the presence of 1, indicating the quenching process. When Sc3N@D5h-C80 was used, the transient absorption was much less intensive. Therefore, the quenching of 3Sc3N@D5h-C80 * by 1 could not be confirmed. Furthermore, we applied time-dependent density functional theory (TD-DFT) calculations of the photoexcited states of Sc3N@C80 to obtain insights into the reaction mechanism. [ABSTRACT FROM AUTHOR]

Exohedral derivatization of endohedral metallofullerenes (EMFs) has been exploited as a useful method for characterizing the structural and chemical properties of EMFs, and for functionalizing them for potential applications. The introduction of heteroatoms, such as electropositive silicon atoms, to fullerene cages is a novel functionalization method that remarkably affects the electronic characteristics of fullerenes. This review comprehensively describes the results of the reactions of monometallofullerene, dimetallofullerene, and trimetallic nitride template EMFs with disilirane, silirane, silylene, and digermirane, which afforded the corresponding silylated and germylated fullerenes. Several examples emphasize that exohedral functionalization regulates the dynamic behaviors of the encapsulated metal atoms and clusters in the fullerene cages. The electronic effects of silyl and germyl groups are represented by comparing the redox properties of silylated and germylated EMFs with those of other EMFs derivatized with carbon-atom-based functional groups. [ABSTRACT FROM AUTHOR]

Relative concentrations of six isomeric Eu@C72--one based on the IPR C72 cage (i.e., obeying the isolated-pentagon rule, IPR), two cages with a pentagon-pentagon junction (symmetries C2 and C2v), a cage with one heptagon, a cage with two heptagons, and a cage with two pentagon-pentagon fusions--are DFT computed using the Gibbs energy in a broad temperature interval. It is shown that the two non-IPR isomers with one pentagon-pentagon junction prevail at any relevant temperature and exhibit comparable populations. The IPR-satisfying structure is disfavored by both energy and entropy. [ABSTRACT FROM AUTHOR]

Photochemical carbosilylation of Lu3N@Ih-C80 was performed using siliranes (silacyclopropanes) to afford the corresponding [5,6]- and [6,6]-adducts. Electrochemical studies indicated that the redox potentials of the carbosilylated derivatives were shifted cathodically in comparison with those of the [5,6]-pyrrolidino adducts. The electronic effect of the silirane addends on Lu3N@Ih-C80 was verified on the basis of density functional theory calculations. [ABSTRACT FROM AUTHOR]

Putting metal atoms or metallic clusters into fullerenes has generated a new class of hybrid molecules, defined as endohedral metallofullerenes (EMFs), possessing novel structures and fascinating properties which are different from those of empty fullerenes. In particular, it has been revealed that the chemical properties of the cage carbons of EMFs depend strongly on the nature of the internal metallic species, such as their electronic configuration, location and even motion. Since the first report describing the successful derivatization of La@C82 in 1995, great efforts have been devoted to the chemical modification of EMFs during the last two decades. Although earlier studies mainly focused on readily available species such as M@C82, M2@C80 and M3N@C80 and the related results have been systematically summarized in our previous review paper (Chem. Commun., 2011, 47, 5942-5957), recent concerns about some relatively rare EMFs have developed rapidly. Moreover, taking advantage of single crystal X-ray crystallography, we can now clearly demonstrate the mutual influences between the internal metallic species and the chemical behaviours of the surrounding cage carbons, and the addends as well. In this article, we present recent achievements in the chemical functionalization of EMFs, which were mainly published during the last four years. For consistency, we will still pay special attention to the role that the metals play in controlling the properties of the whole EMF molecules. In this review, however, we will not only focus on concrete experimental results such as X-ray crystallographic and NMR spectroscopic data but will also include computational studies which have indeed enhanced our understanding of the chemical properties of EMFs. Applicable materials based on EMFs are also mentioned but are not discussed in detail. [ABSTRACT FROM AUTHOR]

Reactions of Sc3N@/h-C80 with aziridine derivatives were conducted to afford the corresponding mono-adducts. A pair of diastereomers of the mono-adduct [5,6]-pyrrolidino-Sc3N@/h-C80 was isolated and characterized by means of mass spectrometry, vis-NIR absorption spectroscopy, and electrochemical measurements. Structural analysis of the mono-adducts was conducted by NMR and single-crystal X-ray structure determinations. [ABSTRACT FROM AUTHOR]

A new chemical method has been applied to isolate isomers of C78. The photochemical cycloaddition of a mixture of C78(D3) and C78(C2v) with a disilirane affords only the mono-adduct of the C2visomer of C78. Its counterpart does not give the mono-adduct with a disilirane. The D3isomer itself and the adduct of the C2visomer of C78with a disilirane are easily separated by a HPLC procedure. A facile oxidative desilylation of the adduct takes place, resulting in the formation of pristine C78(C2v). In this context, the separation and isolation of the two isomers of C78were successfully accomplished by using a silylation–oxidative desilylation process. [ABSTRACT FROM AUTHOR]

Herein we show that the simple preparation and characterization of transparent and conductive thin films of single-walled carbon nanotubes and metal-rich single-walled carbon nanotubes. [ABSTRACT FROM AUTHOR]

Regioselective cycloaddition of adamantylidene carbene to Pr@C2v(9)-C82 affords the first derivative of praseodymium-containing metallo-fullerenes. Single-crystal X-ray crystallographic data in combination with theoretical studies demonstrate that the addition is dictated by the single metal ion encapsulated inside the fullerene cage. [ABSTRACT FROM AUTHOR]

We herein report the investigation of N@C60exposed to laser flash excitation to exhibit the acceleration of the decay of (N@C60)* by the encased N atom. [ABSTRACT FROM AUTHOR]

Dimetallofullerene Ce2@C78 and its bis-silylated derivative (1) were successfully prepared and fully characterized. [ABSTRACT FROM AUTHOR]

The 139La NMR study of the exohedrally functionalized derivatives of La2@C80 metallofullerene, La2@C80(Ar2Si)2CH2 (3a: Ar = Mes, Mes = mesityl, 3b: Ar = Dep, Dep = 2,6-diethylphenyl), reveal that the two La atoms hop between two sites along the equator of the C80 cage. [ABSTRACT FROM AUTHOR]