Hierarchical chiral framework based on a rigid adamantane tripod on Au(111)
Hierarchical chiral framework based on a rigid adamantane tripod on Au(111)
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DOI：
10.1021/ja065893v
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发表时间：
2007-03-07
影响因子：
15
通讯作者：
Kawai, Maki
中科院分区：
文献类型：
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作者：
Katano, Satoshi;Kim, Yousoo;Kawai, Maki
我们使用扫描隧道显微镜 (STM) 在 4.7 K 下研究了 Au(111) 上的三脚架形状的溴金刚烷三硫醇 (BATT) 分子。BATT 的吸附导致在 Au(111) 上形成具有三点接触的高度有序的自组装单层 (SAM)。已发现这些 SAM 的结构具有两层分层手性组织。非手性单体的自组装产生手性三聚体，然后作为手性六角超分子的构建块。 SAM 开始由带状岛中组装分子的外消旋混合物形成，然后当 SAM 层在 hcp 结构域上二维发展时，转变为对映体结构域。这种二维域的手性相变可以由分子-基质和分子间相互作用之间的微妙平衡引起。两个结构因素，S 原子（稳定）和位于 S 原子上方的亚甲基（手性），诱导 Au(111) 上 BATT 的手性排序。
We have investigated the tripod-shaped bromo adamantane trithiol (BATT) molecule on Au(111) using scanning tunneling microscopy (STM) at 4.7 K. Adsorption of BATT leads to formation of highly ordered self-assembled monolayers (SAMs) with three-point contacts on Au(111). The structure of these SAMs has been found to have a two-tiered hierarchical chiral organization. The self-assembly of achiral monomers produces chiral trimers, which then act as the building blocks for chiral hexagonal supermolecules. SAMs begin to form from the racemic mixture of assembled molecules in ribbon-shaped islands, followed by the transformation to enantiomeric domains when SAM layers develop two-dimensionally across hcp domains. Such a chiral phase transition at the two-dimensional domain can arise from a subtle balance between molecule-substrate and intermolecular interactions. Two structural factors, the S atom (stabilization) and the methylene groups (chirality) located just above the S atom, induce the chiral ordering of BATT on Au(111).