Katano Satoshi, Kim Yousoo, Matsubara Hiroaki, Kitagawa Toshikazu, Kawai Maki
Surface Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan.
J Am Chem Soc. 2007 Mar 7;129(9):2511-5. doi: 10.1021/ja065893v. Epub 2007 Feb 6.
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).
我们在4.7 K下使用扫描隧道显微镜（STM）研究了金（111）表面的三脚架状溴代金刚烷三硫醇（BATT）分子。BATT的吸附导致在金（111）上形成具有三点接触的高度有序的自组装单分子层（SAMs）。已发现这些SAMs的结构具有两层分级手性组织。非手性单体的自组装产生手性三聚体，然后这些三聚体作为手性六边形超分子的构建块。SAMs从带状岛中组装分子的外消旋混合物开始形成，当SAM层在hcp域上二维生长时，随后转变为对映体域。二维域中的这种手性相变可能源于分子 - 底物和分子间相互作用之间的微妙平衡。两个结构因素，即S原子（稳定性）和位于S原子正上方的亚甲基（手性），诱导了BATT在金（111）上的手性排序。
