一种新颖的双(米-亚苯基)为基础的-26冠-8穴状配体已被合成。它已被用来在丙酮中制备具有两个具有高缔合常数(6.5×10 5和4.0×10 5 M -1)的百草枯衍生物的两个1:1配合物。在固态下,穴状配体形成具有百草枯的2:1螺纹结构和具有二羟乙基取代的百草枯衍生物的有趣的超分子聚[2]假轮烷烷螺纹结构。通过使用容易获得的3,5-二甲基苯基作为终止剂的立即溶剂蒸发法,它还被用于有效地制备穴状/百草枯的衍生物[2]轮烷。
High-yielding syntheses of two novelcryptands based on bis(m-phenylene)-26-crown-8 are reported. One-step [2+2] cyclization of methyl 3,5-dihydroxybenzoate with tri(ethylene glycol) ditosylate under pseudo-high-dilution conditions gave BMP26C8 (1) in 28 % yield. Reduction of 1 with LAH, followed by deprotonation (NaH) and alkylation with propargyl bromide, afforded the dialkynated BMP26C8 (3) in high
π-stacking interactions, and charge-transfer interactions are thought to be the main driving forces for the formation of these host–guest complexes. These multiple non-covalent interactions may jointly contribute to the complex formation and considerably reinforce the complex stability. Moreover, the complexation between dibenzo-24-crown-8-based cryptand 4 and tropylium hexafluorophosphate 7 can be
醚类冠穴状配体的主机和一个碳正离子之间主-客体复合,六氟磷酸鎓进行了研究。1 H NMR,NOESY NMR和电喷雾电离质谱法来表征这些包合络合物。的对比试验11 H NMR和结合常数表明穴状配体是六氟磷酸鎓比相应的简单冠醚好得多主机。C-H⋯O氢键键合,面-面π堆积相互作用,和电荷转移的相互作用被认为是主要驱动力为这些主-客体复合物的形成。这些多种非共价相互作用可共同促进复合物的形成并显着增强复合物的稳定性。此外,基于二苯并-24-冠-8之间的穴状配体络合4和六氟磷酸鎓7可以通过添加KPF被可逆地控制6 然后DB18C6在1:1级乙腈/氯仿,提供用于超分子化学新阳离子响应性主客体识别基序。
Reversible mechanical protection: building a 3D “suit” around a T-shaped benzimidazole axle
作者:Kelong Zhu、Giorgio Baggi、V. Nicholas Vukotic、Stephen J. Loeb
DOI:10.1039/c7sc00790f
日期:——
The T-shaped benzimidazolium/crown ether recognition motif was used to prepare suit[1]anes. These novel mechanically interlocked molecules (MIMs) were fully characterized by 1H and 13C NMR spectroscopy, single-crystal X-ray diffraction, UV-vis absorption and fluorescence spectroscopy. By conversion to a suit[1]ane, a simple benzimidazole was shown to be protected from deprotonation by strong base.
T形苯并咪唑鎓/冠醚识别基序用于制备正[1]烷。这些新型机械互锁分子 (MIM) 通过1 H 和13 C NMR 光谱、单晶 X 射线衍射、紫外-可见吸收和荧光光谱进行了全面表征。通过转化为丙烷[1]烷,简单的苯并咪唑被证明可以防止强碱的去质子化。此外,还证明了这种独特的三维封装可以实现可逆,从而引入了“可逆机械保护”的概念;一种可能在合成有机化学和分子机械设计中具有潜在应用的保护方法。
Crown‐Ether‐Based Cryptands with Rarely Strong Affinities for Binding Neutral Organic Molecules
approach′ of delicately tunning the non-covalent interactions could be a powerful route to construct molecular hosts that exhibit high selectivity and affinity for guest molecules. Through tailoring spatial fitting and multi non-covalent interactions (especially H-bonding), cryptands with rarely strong affinities for binding neutral guest molecules were achieved.
Two [2]catenanes based on two different cryptand hosts, a dibenzo-24-crown-8-based cryptand and a bis(m-phenylene)-26-crown-8-based cryptand, have been synthesized and characterized. These two cryptand hosts only have a minor difference in chemical structure. However, this minor structural difference leads to big differences in the configurations and packing modes of the resulting catenanes, In addition, from the crystal structures of the two catenanes, we found that the cyclophane guest seems to have a selectivity algorithm and chooses the larger-size rings to go through and interlock with.