Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
Langmuir. 2011 Jul 5;27(13):8205-15. doi: 10.1021/la201413h. Epub 2011 Jun 13.
Shape-persistent rigid phenylene-ethynylene-butadiynylenes form lamellar self-assembled monolayers (SAMs) at the HOPG/TCB interface, which were studied by scanning tunneling microscopy (STM) with submolecular resolution. Substitution of the terminating acetylene functions with polar cyanopropyldimethylsilyl groups leads to 2D phase separation and defined rod-rod interactions, which determine the packing distances between the rigid rods. The results stimulated the connection of rigid rods via septiarylene clamp units. They covalently link two rigid rod units and define the intramolecular rod-rod distance that matches the alkoxy substituent chain lengths. The systems can be described as half-ring structures of two rigid rods connected via a rotatable joint unit. These acetylene-terminated half-ring structures were also oligomerized under Cu and Pd catalysis to yield defined acyclic and cyclic oligomers. Detailed STM studies decoded the molecular origin of the surface patterning of such systems. The dodecyloxy side chains are adsorbed along the HOPG main axes and, together with the alkoxy backbone angle, determine the adsorption direction of the adlayers.
形状保持刚性的苯乙炔-丁二炔在 HOPG/TCB 界面形成层状自组装单分子层 (SAM)，这是通过具有亚分子分辨率的扫描隧道显微镜 (STM) 进行研究的。用极性氰丙基二甲基甲硅烷基取代末端乙炔官能团会导致 2D 相分离和明确的棒-棒相互作用，从而确定刚性棒之间的堆积距离。结果刺激了通过季戊烯夹单元连接刚性棒。它们通过共价键连接两个刚性棒单元，并定义了与烷氧基取代链长度匹配的分子内棒-棒距离。这些系统可以描述为通过可旋转连接单元连接的两个刚性棒的半环结构。这些乙炔端接的半环结构也在 Cu 和 Pd 催化下聚合，得到了定义明确的无环和环状低聚物。详细的 STM 研究解码了这些系统表面图案化的分子起源。十二烷氧基侧链沿 HOPG 主轴吸附，并且与烷氧基主链角一起决定了吸附层的吸附方向。
