The successful preparation and isolation of the mixed-metal endohedral fullerene, LaSc(2)N@I(h)-C(80), and its structural characterization by single-crystal X-ray diffraction are reported. Results from chemically adjusting plasma temperature, energy, and reactivity (CAPTEAR) experiments indicate that a 10 wt % addition of Cu(NO(3))(2)·2.5H(2)O to a mixture of La(2)O(3) and Sc(2)O(3) decreases the amount of C(60) and C(70) found in soot extracts by an order of magnitude. By combining a stoichiometric 2-fold excess of La to Sc atoms in the plasma reactor, an extract containing a greater abundance of LaSc(2)N@I(h)-C(80) relative to Sc(3)N@I(h)-C(80) was obtained. Alternatively, the stir and filter approach (SAFA method) can be used to remove the empty cage fullerenes from a carbon soot sample prepared without using Cu(NO(3))(2)·2.5H(2)O. LaSc(2)N@I(h)-C(80) has been characterized by UV/vis absorption spectroscopy and by single-crystal X-ray diffraction. Ordered crystals with nearly identical orientations of the endohedral relative to the porphyrin have been obtained by cocrystallization of LaSc(2)N@I(h)-C(80) with either Ni(II)(OEP) or H(2)(OEP). The LaSc(2)N unit is planar, although earlier computations suggested that it would be pyramidal.

Single-crystal X-ray diffraction studies of Sc(2)(μ(2)-S)@C(s)(6)-C(82)·Ni(II)(OEP)·2C(6)H(6) and Sc(2)(μ(2)-S)@C(3v)(8)-C(82)·Ni(II)(OEP)·2C(6)H(6) reveal that both contain fully ordered fullerene cages. The crystallographic data for Sc(2)(μ(2)-S)@C(s)(6)-C(82)·Ni(II)(OEP)·2C(6)H(6) show two remarkable features: the presence of two slightly different cage sites and a fully ordered molecule Sc(2)(μ(2)-S)@C(s)(6)-C(82) in one of these sites. The Sc-S-Sc angles in Sc(2)(μ(2)-S)@C(s)(6)-C(82) (113.84(3)°) and Sc(2)(μ(2)-S)@C(3v)(8)-C(82) differ (97.34(13)°). This is the first case where the nature and structure of the fullerene cage isomer exerts a demonstrable effect on the geometry of the cluster contained within. Computational studies have shown that, among the nine isomers that follow the isolated pentagon rule for C(82), the cage stability changes markedly between 0 and 250 K, but the C(s)(6)-C(82) cage is preferred at temperatures ≥250 °C when using the energies obtained with the free encapsulated model (FEM). However, the C(3v)(8)-C(82) cage is preferred at temperatures ≥250 °C using the energies obtained by rigid rotor-harmonic oscillator (RRHO) approximation. These results corroborate the fact that both cages are observed and likely to trap the Sc(2)(μ(2)-S) cluster, whereas earlier FEM and RRHO calculations predicted only the C(s)(6)-C(82) cage is likely to trap the Sc(2)(μ(2)-O) cluster. We also compare the recently published electrochemistry of the sulfide-containing Sc(2)(μ(2)-S)@C(s)(6)-C(82) to that of corresponding oxide-containing Sc(2)(μ(2)-O)@C(s)(6)-C(82).

A family of highly stable (poly)perfluoroalkylated metallic nitride cluster fullerenes was prepared in high-temperature reactions and characterized by spectroscopic (MS, (19)F NMR, UV-vis/NIR, ESR), structural and electrochemical methods. For two new compounds, Sc(3)N@C(80)(CF(3))(10) and Sc(3)N@C(80)(CF(3))(12,) single crystal X-ray structures are determined. Addition pattern guidelines for endohedral fullerene derivatives with bulky functional groups are formulated as a result of experimental ((19)F NMR spectroscopy and single crystal X-ray diffraction) studies and exhaustive quantum chemical calculations of the structures of Sc(3)N@C(80)(CF(3))(n) (n = 2-16). Electrochemical studies revealed that Sc(3)N@C(80)(CF(3))(n) derivatives are easier to reduce than Sc(3)N@C(80), the shift of E(1/2) potentials ranging from +0.11 V (n = 2) to +0.42 V (n = 10). Stable radical anions of Sc(3)N@C(80)(CF(3))(n) were generated in solution and characterized by ESR spectroscopy, revealing their (45)Sc hyperfine structure. Facile further functionalizations via cycloadditions or radical additions were achieved for trifluoromethylated Sc(3)N@C(80) making them attractive versatile platforms for the design of molecular and supramolecular materials of fundamental and practical importance.

The new endohedral fullerene, Sc-2(mu(2)-O)@C-s(6)-C-82, has been isolated from the carbon soot obtained by electric arc generation of fullerenes utilizing graphite rods doped with 90% Sc2O3 and 10% Cu (w/w). Sc-2(mu(2)-O)@ C-s(6)-C-82 has been characterized by single crystal X-ray diffraction, mass spectrometry, and UV/vis spectroscopy. Computational studies have shown that, among the nine isomers that follow the isolated pentagon rule (IPR) for C-82, cage 6 with C-s symmetry is the most favorable to encapsulate the cluster at T > 1200 K. Sc-2(mu(2)-O) C-s(6)-C-82 is the first example in which the relevance of the thermal and entropic contributions to the stability of the fullerene isomer has been clearly confirmed through the characterization of the X-ray crystal structure.

ChemInformVolume 41, Issue 32 Isocyclic Compounds ChemInform Abstract: Redox-Tuning Endohedral Fullerene Spin States: From the Dication to the Trianion Radical of Sc3N@C80(CF3)2 in Five Reversible Single-Electron Steps. Alexey A. Popov, Alexey A. Popov Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorNatalia B. Shustova, Natalia B. Shustova Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorAnna L. Svitova, Anna L. Svitova Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorMary A. Mackey, Mary A. Mackey Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorCurtis E. Coumbe, Curtis E. Coumbe Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorJ. Paige Phillips, J. Paige Phillips Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorSteven Stevenson, Steven Stevenson Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorSteven H. Strauss, Steven H. Strauss Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorOlga V. Boltalina, Olga V. Boltalina Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorLothar Dunsch, Lothar Dunsch Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this author Alexey A. Popov, Alexey A. Popov Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorNatalia B. Shustova, Natalia B. Shustova Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorAnna L. Svitova, Anna L. Svitova Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorMary A. Mackey, Mary A. Mackey Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorCurtis E. Coumbe, Curtis E. Coumbe Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorJ. Paige Phillips, J. Paige Phillips Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorSteven Stevenson, Steven Stevenson Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorSteven H. Strauss, Steven H. Strauss Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorOlga V. Boltalina, Olga V. Boltalina Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this authorLothar Dunsch, Lothar Dunsch Dep. Electrochem., Inst. Festkoerper- Werkstoffforsch. Dresden, D-01069 Dresden, GermanySearch for more papers by this author First published: 23 July 2010 https://doi.org/10.1002/chin.201032107AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume41, Issue32August 10, 2010 RelatedInformation

The new endohedral fullerene, Sc(2)(mu(2)-O)@C(s)(6)-C(82), has been isolated from the carbon soot obtained by electric arc generation of fullerenes utilizing graphite rods doped with 90% Sc(2)O(3) and 10% Cu (w/w). Sc(2)(mu(2)-O)@C(s)(6)-C(82) has been characterized by single crystal X-ray diffraction, mass spectrometry, and UV/vis spectroscopy. Computational studies have shown that, among the nine isomers that follow the isolated pentagon rule (IPR) for C(82), cage 6 with C(s) symmetry is the most favorable to encapsulate the cluster at T > 1200 K. Sc(2)(mu(2)-O)@C(s)(6)-C(82) is the first example in which the relevance of the thermal and entropic contributions to the stability of the fullerene isomer has been clearly confirmed through the characterization of the X-ray crystal structure.

We report the synthesis and electronic stabilization of La(3)N@C(79)N. Unsuccessful efforts to encapsulate bulky La(3)N clusters in small C(80) cages have been attributed to large ionic radii. The preferred species for La(3)N clusters in all-carbon cages is La(3)N@C(96). A surprising finding is the synthesis of La(3)N@C(79)N, a new metallofullerene present in higher abundance than La(3)N@C(96). This reduction in cage size from 96 to 80 atoms reflects the significance and role of electronic effects. To understand the geometric and electronic properties of this first metallic nitride azafullerene (M(3)N@C(79)N, M = La), density functional theory (DFT) investigations were performed on a number of isomers. Results indicate a preferred N-substitution at the 665 junction site on the cage in lieu of a 666 substitution. The relative stabilities of different isomers can be well reproduced by using the minimum distance between the metal atom and the nitrogen atom of the cage (R(N'M)(min)). Long R(N'M)(min) values indicate distant contacts between six atoms that bear significantly large positive charges: the three metal atoms and the three carbon atoms bonded with the nitrogen atom in the cage, which are favored. These results suggest a dominant electronic effect on the stabilities of metalloazafullerenes. Interestingly, spin densities of the 665 substitution isomers of La(3)N@C(79)N are located predominantly in the metal cluster, while spin densities of the 666 substitution isomers are primarily on the cage.

The compounds Sc(3)N@(C(80)-I(h)(7))(CF(3))(14) (1) and Sc(3)N@(C(80)-I(h)(7))(CF(3))(16) (2) were prepared by heating Sc(3)N@C(80)-I(h)(7) and Ag(CF(3)CO(2)) to 350 degrees C in a sealed tube. The structures of 1 and 2 were determined by single-crystal X-ray diffraction. They are the first X-ray structures of any endohedral metallofullerene with more than four cage C(sp(3)) atoms. The structures exhibit several unprecedented features for metallic nitride fullerenes, including multiple cage sp(3) triple-hexagon junctions (four on 1 and eight on 2), no cage disorder and little (2) or no (1) endohedral atom disorder, high-precision (C-C esd's are 0.005 A for 1 and 0.002 A for 2), an isolated aromatic C(sp(2))(6) hexagon on 2, and two negatively charged isolated aromatic C(sp(2))(5)(-) pentagons on 2 that are bonded to one of the Sc atoms. DFT calculations are in excellent agreement with the two Sc(3)N conformations observed for 2 (DeltaE(calc) = 0.36 kJ mol(-1); DeltaE(exp) = 0.26(2) kJ mol(-1)).

The adhesive properties, as measured by bulk tack analysis, are found to decrease in blends of isomerically pure Sc3N@I(h)-C80 metallic nitride fullerene (MNF) and polystyrene-block-polyisoprene-block-polystyrene (SIS) copolymer pressure-sensitive adhesive under white light irradiation in air. The reduction of tack is attributed to the in situ generation of 1O2 and subsequent photooxidative cross-linking of the adhesive film. Comparisons are drawn to classical fullerenes C60 and C70 for this process. This work represents the first demonstration of 1O2 generating ability in the general class of MNFs (M3N@C80). Additional support is provided for the sensitizing ability of Sc3N@I(h)-C80 through the successful photooxygenation of 2-methyl-2-butene to its allylic hydroperoxides in benzene-d(6) under irradiation at 420 nm, a process that occurs at a rate comparable to that of C(60). Photooxygenation of 2-methyl-2-butene is found to be influenced by the fullerene sensitizer concentration and O2 flow rate. Molar extinction coefficients are reported for Sc3N@I(h)-C80 at 420 and 536 nm. Evaluation of the potential antimicrobial activity of films prepared in this study stemming from the in situ generation of 1O2 led to an observed 1 log kill for select Gram-positive and Gram-negative bacteria.