Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 Japan.
J Am Chem Soc. 2009 Dec 9;131(48):17583-90. doi: 10.1021/ja904481j.
A series of alkyl- and alkoxy-substituted rhombic-shaped bisDBA derivatives 1a-d, 2a, and 2b were synthesized for the purpose of the formation of porous networks at the 1,2,4-trichlorobenzene (TCB)/graphite interface. Depending on the alkyl-chain length and the solute concentration, bisDBAs exhibit five network structures, three porous structures (porous A, B, and C), and two nonporous structures (nonporous D and E), which are attributed to their rhombic core shape and the position of the substituents. BisDBAs 1a and 1b with the shorter alkyl chains favorably form a porous structure, whereas bisDBAs 1c and 1d with the longer alkyl chains are prone to form nonporous structures. However, upon dilution, nonporous structures are typically transformed into porous ones, a trend that can be understood by the effect of surface coverage, molecular density, and intermolecular interactions on the system's enthalpy. Furthermore, porous structures are stabilized by the coadsorption of solvent molecules. The most intriguing porous structure, the Kagome pattern, was formed for all compounds at least to some extent, and the size of its triangular and hexagonal pores could be tuned by the alkyl-chain length. The present study proves that the concentration control is a powerful and general tool for the construction of porous networks at the liquid-solid interface.
为了在 1,2,4-三氯苯（TCB）/石墨界面形成多孔网络，合成了一系列烷基和烷氧基取代的菱形双二苯乙炔（DBA）衍生物 1a-d、2a 和 2b。根据烷基链长度和溶质浓度，双 DBA 表现出五种网络结构、三种多孔结构（多孔 A、B 和 C）和两种非多孔结构（非多孔 D 和 E），这归因于它们的菱形核心形状和取代基的位置。具有较短烷基链的双 DBA 1a 和 1b 有利于形成多孔结构，而具有较长烷基链的双 DBA 1c 和 1d 则容易形成非多孔结构。然而，稀释后，非多孔结构通常会转化为多孔结构，这种趋势可以通过表面覆盖率、分子密度和分子间相互作用对系统焓的影响来理解。此外，多孔结构可以通过溶剂分子的共吸附来稳定。对于所有化合物，至少在某种程度上形成了最有趣的 Kagome 图案多孔结构，其三角形和六边形孔的大小可以通过烷基链长度来调节。本研究证明浓度控制是在固液界面构建多孔网络的一种强大而通用的工具。
