Chemical reactivity of sc3n @ c80 and la2 @ c80.

Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
Journal of the American Chemical Society (Impact Factor: 10.68). 08/2005; 127(28):9956-7. DOI: 10.1021/ja052534b
Source: PubMed

ABSTRACT Sc3N@C80 has a lower thermal reactivity than La2@C80, although Sc3N@C80 has the same carbon cage (Ih) and oxidation state (C806-) as La2@C80. This result is attributed to the difference in the energy level and distribution of LUMO between Sc3N@C80 and La2@C80.

  • Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/2009; 82(2):171-181.
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    ABSTRACT: Two isomeric [5,6]-pyrrolidine-I(h)-Sc(3)N@C(80) electron donor-acceptor conjugates containing triphenylamine (TPA) as the donor system were synthesized. Electrochemical and photophysical studies of the novel conjugates were made and compared with those of their C(60) analogues, in order to determine (i) the effect of the linkage position (N-substituted versus 2-substituted pyrrolidine) of the donor system in the formation of photoinduced charge separated states, (ii) the thermal stability toward the retro-cycloaddition reaction, and (iii) the effect of changing C(60) for I(h)-Sc(3)N@C(80) as the electron acceptor. It was found that when the donor is connected to the pyrrolidine nitrogen atom, the resulting dyad produces a significantly longer lived radical pair than the corresponding 2-substituted isomer for both the C(60) and I(h)-Sc(3)N@C(80) dyads. In addition to that, the N-substituted TPA-I(h)-Sc(3)N@C(80) dyad has much better thermal stability than the 2-substituted one. Finally, the I(h)-Sc(3)N@C(80) dyads have considerably longer lived charge separated states than their C(60) analogues, thus approving the advantage of using I(h)-Sc(3)N@C(80) instead of C(60) as the acceptor for the construction of fullerene based donor-acceptor conjugates. These findings are important for the design and future application of I(h)-Sc(3)N@C(80) dyads as materials for the construction of plastic organic solar cells.
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    ABSTRACT: The reaction mechanism and regioselectivity of the Diels–Alder reactions of C68 and Sc3N@C68, which violate the isolated pentagon rule, were studied with density functional theory calculations. For C68, the [5,5] bond is the most favored thermodynamically, whereas the cycloaddition on the [5,6] bond has the lowest activation energy. Upon encapsulation of the metallic cluster, the exohedral reactivity of Sc3N@C68 is reduced remarkably owing to charge transfer from the cluster to the fullerene cage. The [5,5] bond becomes the most reactive site thermodynamically and kinetically. The bonds around the pentagon adjacency show the highest chemical reactivity, which demonstrates the importance of pentagon adjacency. Furthermore, the viability of Diels–Alder cycloadditions of several dienes and Sc3N@C68 was examined theoretically. o-Quinodimethane is predicted to react with Sc3N@C68 easily, which implies the possibility of using Diels–Alder cycloaddition to functionalize Sc3N@C68.
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