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Isolation and properties of small-bandgap fullerenes

机译:小带隙富勒烯的分离与性能

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摘要

The diversity of molecular structures exhibited by fullerenes suggests a wide range of interesting and useful properties. Several fullerenes are now considered to be well characterized, but only minor variations in their chemical and physical properties have been observed. Here we show that there are in fact two distinct classes of fullerenes, with some very different chemical properties. Members of the first class, typified by C_(60) and C_(70), have large energy gaps between the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO), and are soluble in many organic solvents. The second, previously unrecognized class is represented by C_(74) and selected isomers of the higher fullerenes, such as that of C_(80) with icosahedral symmetry: these are either free radicals or have small HOMO-LUMO gaps. Like radical metallo-fullerenes, they are kinetically unstable and react readily to form insoluble, polymerized solids. These intermolecular bonds can be broken by electrochemical reduction. After reducing them to soluble anions, we have been able to isolate and characterize these new fullerenes.
机译:富勒烯表现出的分子结构的多样性表明了广泛的有趣和有用的性质。现在认为几种富勒烯具有良好的特征,但仅观察到其化学和物理性质的微小变化。在这里,我们表明实际上有两种不同的富勒烯类,它们的化学性质有些不同。以C_(60)和C_(70)为代表的第一类成员,在最高占据和最低未占据分子轨道(HOMO和LUMO)之间具有较大的能隙,并且可溶于许多有机溶剂。第二个以前无法识别的类别由C_(74)和较高的富勒烯的选定异构体(例如具有二十面体对称的C_(80)的异构体)表示:它们是自由基或具有较小的HOMO-LUMO间隙。像自由基金属富勒烯一样,它们在动力学上不稳定,容易反应形成不溶的聚合固体。这些分子间键可通过电化学还原而断裂。将它们还原为可溶性阴离子后,我们已经能够分离并表征这些新的富勒烯。

著录项

  • 来源
    《Nature》 |1998年第6686期|p.668-671|共4页
  • 作者单位
  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 自然科学总论;
  • 关键词

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