C74F38: an exohedral derivative of a small-bandgap fullerene with D3 symmetry.
C74F38: an exohedral derivative of a small-bandgap fullerene with D3 symmetry.
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DOI：
10.1002/anie.200352960
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发表时间：
2004-02
影响因子：
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通讯作者：
A. Goryunkov;V. Y. Markov;I. Ioffe;R. D. Bolskar;M. Diener;Igor V. Kuvychko;S. Strauss;O. Boltalina
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文献类型：
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作者：
A. Goryunkov;V. Y. Markov;I. Ioffe;R. D. Bolskar;M. Diener;Igor V. Kuvychko;S. Strauss;O. Boltalina
具有大HOMO-LUMO能隙的甲苯可溶富勒烯（如C60，C70）已被广泛研究。[1]相比之下，具有小于0.5 eV的HOMO-LUMO间隙的甲苯不溶性富勒烯由于其低溶解度和空气敏感性而没有被广泛研究。后者的一个重要实例是C74，其可具有小至0.05 eV的HOMO-LUMO能隙。[2-4]在这里，我们提出了一个单一的regioisomer（对映异构体）的C74F38富勒烯衍生物与D3对称性（表示D3-C74F38），第一外衍生物C74的分离和表征。1998年首次报道了小带隙（SBG）富勒烯C74的纯样品。[2]TDA的Diener和阿尔福德通过厌氧HPLC处理含有稳定的C74 2 β离子的溶液，然后再氧化C74 2 β富集级分以产生固体C74。[2]直到那时，空的（即无金属的）C74的不溶性，这可能是小的HOMO-LUMO间隙的结果，[2]阻止了对其外面体衍生物化学的探索。然而，有迹象表明，一些氟[74]富勒烯可能被制备。气相二氟单阴离子C74F2在1994年通过努森池质谱法观察到。[5]值得注意的是，C74 F2中的C3F键似乎比C60 F2中的C3F键和C70 F2中的C3F键更强。[6]此外，最近的研究表明，一组特定的努森电池条件导致C74F38+作为主要的气相[74]富勒烯物种的产生。[7]众所周知，高度氟化的[60]富勒烯是稳定的，并且具有比母体富勒烯C60更高的挥发性和溶解性。[8，9]考虑到这一点，
Toluene-soluble fullerenes with large HOMO–LUMO energy gaps (eg, C60, C70) have been intensely studied.[1] In contrast, toluene-insoluble fullerenes with HOMO–LUMO gaps less than 0.5 eV have not been extensively studied due to their low solubility and air sensitivity. An important example of the latter is C74, which may have a HOMO–LUMO gap as small as 0.05 eV.[2–4] We present here the isolation and characterization of a single regioisomer (pair of enantiomers) of the C74F38 fullerene derivative with D3 symmetry (denoted D3-C74F38), the first exohedral derivative of C74. Pure samples of the small-bandgap (SBG) fullerene C74 were reported for the first time in 1998.[2] Diener and Alford at TDA processed solutions containing the stable C74 2À ion by anaerobic HPLC, then reoxidized the C74 2À-enriched fraction to yield solid C74.[2] Up until that point, the insolubility of empty (ie, metal-free) C74, which may be a consequence of the small HOMO–LUMO gap,[2] had prevented the exploration of its exohedral derivative chemistry. However, there were indications that some fluoro [74] fullerenes might be prepared. The gas-phase difluoro monoanion C74F2 À was observed in 1994 by Knudsen-cell mass spectrometry.[5] Significantly, the CÀF bonds in C74F2 À appeared to be stronger than the CÀF bonds in C60F2 À and C70F2 À.[6] In addition, it was recently shown that a specific set of Knudsen-cell conditions led to the generation of C74F38+ as the dominant gas-phase [74] fullerene species.[7] Highly fluorinated [60] fullerenes are well known to be stable and to have higher volatilities and solubilities than the parent fullerene C60.[8, 9] With this in mind,