Institut National de la Recherche Scientifique, Centre Énergie, Matériaux, Télécommunications, Varennes, QC, Canada.
Langmuir. 2013 Jun 18;29(24):7318-24. doi: 10.1021/la3047593. Epub 2013 Feb 6.
Investigations of the self-assembly of simple molecules at the solution/solid interface can provide useful insight into the general principles governing supramolecular chemistry in two dimensions. Here, we report on the assembly of 3,4',5-biphenyl tricarboxylic acid (H3BHTC), a small hydrogen bonding unit related to the much-studied 1,3,5-benzenetricarboxylic acid (trimesic acid, TMA), which we investigate using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. STM images show that H3BHTC assembles by itself into an offset zigzag chain structure that maximizes the surface molecular density in favor of maximizing the number density of strong cyclic hydrogen bonds between the carboxylic groups. The offset geometry creates "sticky" pores that promote solvent coadsorption. Adding coronene to the molecular solution produces a transformation to a high-symmetry host-guest lattice stabilized by a dimeric/trimeric hydrogen bonding motif similar to the TMA flower structure. Finally, we show that the H3BHTC lattice firmly immobilizes the guest coronene molecules, allowing for high-resolution imaging of the coronene structure.
在溶液/固界面上对简单分子的自组装进行研究，可以为二维超分子化学的一般原理提供有用的见解。在这里，我们报告了 3,4',5-联苯三甲酸（H3BHTC）的组装，这是一个与研究较多的 1,3,5-苯三甲酸（均苯三甲酸，TMA）相关的小氢键单元，我们使用扫描隧道显微镜（STM）和密度泛函理论（DFT）计算对其进行了研究。STM 图像表明，H3BHTC 自行组装成一个偏移的锯齿链结构，最大限度地提高了表面分子密度，有利于最大限度地增加羧酸基团之间强循环氢键的密度。这种偏移的几何形状会产生“粘性”的孔，促进溶剂共吸附。将蒄添加到分子溶液中会产生转变，形成由二聚体/三聚体氢键模式稳定的高对称性主体-客体晶格，类似于 TMA 花状结构。最后，我们表明 H3BHTC 晶格能牢固地固定客体蒄分子，从而能够对蒄的结构进行高分辨率成像。
