Efficient Synthesis and Astonishing Supramolecular Architectures of Several Symmetric Macrolactams
作者:Pierre Baillargeon、Sylvain Bernard、David Gauthier、Rachid Skouta、Yves L. Dory
DOI:10.1002/chem.200700522
日期:2007.11.16
from isotropic media. The overall dipoles in the crystals from lactams 1 and 4, which result mostly from the alignment of amide groups, are zero and large, respectively. Macrolactam 2 displays an astonishing isomorphism when allowed to cool down in anisotropic liquid crystal solutions. Large hollow hexagonal tubes are then obtained through a fractal process. Contrary to the three previous rings, 3 yields
四个C(n)对称大环内酰胺环-[NH-CH(2)-CH = CH-CH(2)-CO](n)的合成(1,n = 2; 2,n = 3; 3, n = 4)和环-[NH-CH(2)-CH(2)-CH = CH-CO](3)(4)已通过两种方法实现。线性途径导致前体,其随后在单独的步骤中被大环化。第二种收敛方法依赖于目标的对称性:它包括适当激活的亚基,这些亚基会受到大环化条件的影响。亚基首先低聚,然后环化以形成纯的大内酰胺或混合物。大内酰胺单元1、2和4通过弱相互作用(氢键和范德华力)相互堆叠,分别形成无穷的正方形,矩形和三角形棱柱。这些堆叠进一步并排包装在从各向同性介质中生长的晶体中。内酰胺1和4的晶体中的总偶极子分别为零和大,主要是由酰胺基团的排列引起的。当在各向异性液晶溶液中冷却时,Macrolactam 2表现出惊人的同构性。然后通过分形过程获得大型空心六角形管。与前面的三个环相反,3产生没有任何形状的棱镜的晶体。