Development of Ordered Monolayer Based on the Self Assembly of Molecular Tripods

1)分子三脚架-二茂铁二元体及其单层的合成合成了由分子三脚架和二茂铁组成的二元体，通过不同长度的低聚（苯乙烯）连接。三脚架有一个坚硬的金刚烷核心，三个CH_2SH腿附着在上面，以便在金表面进行化学吸附。在Au（111）表面制备了自组装膜，并用电化学测量方法对其进行了分析。单分子层的表面密度与连接剂的长度无关，表明相邻的二茂铁单元由于金刚烷和线性连接剂的刚性框架而具有均匀的分子间距离。结果还表明相邻二茂铁单元之间的相互作用可以忽略不计。这表明每个二茂铁单元与相邻的分子保持独立，表明这些二茂铁具有作为分子记忆的潜在用途。2)扩展分子三脚架及其单层结构的合成合成了以C(CH_3)2SH取代CH_2SH的新型金刚烷三脚架。由于两个甲基的体积较大，每个三脚架分子预计会占据更大的面积，从而导致更大的分子距离。在Au（111）表面对该新三硫醇的自组装单层进行还原脱附实验，结果表明，该新三硫醇的分子距离（10.9 A）明显宽于没有甲基的情况。未来合成这种新三脚架和功能分子单元的二联体将使形成大尺寸功能分子的单层成为可能

1) Synthesis of Molecular Tripod-Ferrocene Dyads and Their MonolayersDyads consisting of a molecular tripod and ferrocene, connected through oligo (phenyleneethynylene) linkers of different lengths, were synthesized. The tripod has a rigid adamantane core to which three CH_2SH legs are attached in order to enable chemisorption on gold surface. The self-assembled monolayers of these dyads were prepared on Au (111) surface and analyzed by means of electrochemical measurements. The surface densities of the monolayers were shown to be constant irrespective of the length of the linker, demonstrating that the adjacent ferrocene units are fixed with a uniform intermolecular distance due to the rigid framework of adamantane and linear linker. It was also shown that there is negligible interaction among neighboring ferrocene units. This indicates that each ferrocene unit is kept independent from adjacent molecules, suggesting that these dyads are of potential use as molecular memories.2) Synthesis of an Extended Molecular Tripod and Its MonolayerA new adamantane tripod, having C(CH_3)2SH groups in place of the CH_2SH groups, was synthesized. Owing to the bulkiness of the two methyl groups, each tripod molecule is expected to occupy an increased area, resulting in greater molecular distance. Reductive desorption experiments for the self-assembled monolayer on Au(111) surface of this new trithiol showed that the molecular distance is significantly wider(10.9 A) than without the methyl groups. Future synthesis of dyads of this new tripod and functional molecular units would enable formation of monolayers of large-sized functional molecules