Covalent template approach toward functionalized oligo-alkyl-substituted shape-persistent macrocycles: Synthesis and properties of rings with a loop
Covalent template approach toward functionalized oligo-alkyl-substituted shape-persistent macrocycles: Synthesis and properties of rings with a loop
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DOI：
10.1021/cm051386l
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发表时间：
2005-10
影响因子：
8.6
通讯作者：
A. Ziegler;W. Mamdouh;An Ver Heyen;M. Surin;H. Uji‐i;Mohammed M. S. Abdel-Mottaleb;F. D. De Schryver-F.-D.-De-Sc
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文献类型：
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作者：
A. Ziegler;W. Mamdouh;An Ver Heyen;M. Surin;H. Uji‐i;Mohammed M. S. Abdel-Mottaleb;F. D. De Schryver-F.-D.-De-Sc
研究了具有环外低烷基和环内双（羟甲基）联苯二酯的形状持久大环的合成、性质和构象。制备的关键步骤是刚性二乙炔的模板支撑玻璃偶联，该偶联可以以81%的收率获得循环产物。与最初的预期相反，化合物不表现出液晶相。这可以用分子的非平面构象来解释，因为联苯桥比环的直径长。另一方面，扫描隧道显微镜研究表明，环内联苯桥可以与石墨上的大环的芳香主链位于同一平面上。涉及分子力学和分子动力学模拟的模型揭示了这种明显的不一致，表明分子在没有固体支撑的情况下采用非平面构象，而平面化需要p。
The synthesis, properties, and conformation of shape-persistent macrocycles with extraannular oligo-alkyl groups and an intraannular bis(hydroxymethyl)biphenylene diester are investigated. The key step in the preparation is the template-supported Glaser coupling of rigid bisacetylenes which allows obtaining the cyclic product in 81% yield. Contrary to the initial expectations, the compounds do not exhibit liquid crystalline phases. This could be explained by a nonplanar conformation of the molecules because the biphenylene bridge is longer than the diameter of the rings. On the other hand, scanning tunneling microscopy investigations indicate that the intraannular biphenylene bridge can be located in the same plane as the aromatic backbone of the macrocycles on graphite. Modeling involving molecular mechanics and molecular dynamics simulations unraveled this apparent inconsistency by showing that the molecules adopt a nonplanar conformation in the absence of the solid support whereas planarization takes p...