Self-assembled graphitic nanotubes with one-handed helical arrays of a chiral amphiphilic molecular graphene
Self-assembled graphitic nanotubes with one-handed helical arrays of a chiral amphiphilic molecular graphene
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DOI：
10.1073/pnas.0500852102
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发表时间：
2005-08-02
影响因子：
11.1
通讯作者：
Aida, T
中科院分区：
文献类型：
--
作者：
Jin, W;Fukushima, T;Aida, T
具有两个手性氧烷基侧链和两个亲油侧链的双子型手性两亲性六周六苯并冠烯的自组装产生了具有单手螺旋手性的石墨纳米管。纳米管的特征是具有极高的长径比>；1,000，直径均匀，直径20 nm，壁厚3 nm。通过将点手性有效地转化为超分子螺旋手性，分别从两亲分子的(S)和(R)对映体获得了具有右旋和左旋螺旋意义的纳米管。(S)和(R)-对映体以不同的摩尔比共组装得到纳米管，其圆二色谱在很大范围内(100-20%)的对映体过量几乎不变。由此观察到的高水平的手性放大表明了自组装过程中的远程协同作用。与之形成鲜明对比的是，具有手性亲脂侧链的六苯并冠烯两亲分子没有形成纳米管组装。本工作证明了非共价体系中的多数规则，并为实现分子螺线管提供了一种合成策略。
Self-assembly of a Gemini-shaped, chiral amphiphilic hexa-peri-hexabenzocoronene having two chiral oxyalkylene side chains, along with two lipophilic side chains, yields graphitic nanotubes with one-handed helical chirality. The nanotubes are characterized by an extremely high aspect ratio of > 1,000 and have a uniform diameter of 20 nm and a wall thickness of 3 nm. The nanotubes with right- and left-handed helical senses were obtained from the (S)- and (R)-enantiomers of the amphiphile, respectively, due to an efficient translation of point chirality into supramolecular helical chirality. The (S)- and (R)-enantiomers coassemble at varying mole ratios to give nanotubes, whose circular dichroism profiles are almost unchanged over a wide range of the enantiomeric excess of the amphiphile (100-20 %). The high level of chirality amplification thus observed indicates a long-range cooperativity in the self-assembling process. In sharp contrast, a hexabenzocoronene amphiphile with chiral lipophilic side chains did not form nanotubular assemblies. The present work demonstrates the majority rule in noncovalent systems and also may provide a synthetic strategy toward realization of molecular solenoids.