• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Efficient Preparation of Separable Pseudo[n]rotaxanes by Selective Threading of Oligoalkylammonium Salts with Cucurbit[7]uril
【24h】

Efficient Preparation of Separable Pseudo[n]rotaxanes by Selective Threading of Oligoalkylammonium Salts with Cucurbit[7]uril

机译：葫芦[7]尿素对低聚烷基铵盐的选择性穿线有效制备可分离的假[n]轮烷

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We describe the efficient preparation of well-defined, homogeneous pseudo[n]rotaxanes (n=2, 3, 4, 5) by the selective threading of oligoalkylammonium salts with cucurbit[7]uril (CB[7]) and the subsequent simple separation of the pure pseudo[n]rotaxanes from the complicated system. A series of well-defined oligoalkylammonium salts were prepared by stepwise synthesis and their molecular recognition and self-assembly with a solution of CB[7] in CF3CO2D/D2O (1:1 v/v) were investigated. As a result of the high affinity of CB[7] to the p-xylene diammonium units (-NH2 +CH2C6H4CH2NH2 +-) in the oligoalkylammonium salts, the CB[7] rings threaded onto these cationic threads to form pseudorotaxane structures. Interestingly, due to the repulsive dipole–dipole electrostatic interactions between the CB[7] units and steric hindrance, the threading process exhibited a high selectivity and a unique self-assembling mode was discovered in which two CB[7] units cannot bind the same ammonium site. The as-formed well-defined pseudo[n]- rotaxanes can be easily separated as pure compounds from the mixture by simple counterion exchange with NH4PF6 and the pure pseudo[n]rotaxanes are stable and partially soluble in normal organic solvents. Such facile preparation and separation are mainly ascribed to the high binding constant between CB[7] and the oligoalkylammonium salts and the unique solubility of CB[7] in protonic acid. As most pseudorotaxanes reported in the literature exist as a dynamic mixture and their separation is usually difficult, our research represents one good example in which pure pseudo[n]rotaxanes (n= 2, 3, 4, 5) can be obtained by a simple “threading-followed-by-precipitation” method.
机译：我们描述了通过葫芦丝[7]尿素（CB [7]）选择性穿入低级烷基铵盐的方法，有效地制备了定义明确的均质假[n]轮烷（n = 2、3、4、5）从复杂的系统中分离纯正[n]轮烷。通过逐步合成制备了一系列定义明确的寡烷基铵盐，并研究了它们在CF3CO2D / D2O（1：1 v / v）中的CB [7]溶液的分子识别和自组装作用。由于CB [7]对寡烷基铵盐中的对二甲苯二铵单元（-NH2 + CH2C6H4CH2NH2 +-）具有高度亲和力，因此CB [7]环旋接到这些阳离子线上以形成假轮烷结构。有趣的是，由于CB [7]单元之间的排斥性偶极-偶极静电相互作用和空间位阻，穿线过程显示出高选择性，并且发现了独特的自组装模式，其中两个CB [7]单元无法结合相同的铵位。通过与NH4PF6进行简单的离子交换，可以很容易地从混合物中分离出形式明确的假[n]-轮烷，并将其作为纯化合物分离，而且纯的假[n]-轮烷是稳定的，并且部分溶于正常的有机溶剂。这种简便的制备和分离主要归因于CB [7]与低级烷基铵盐之间的高结合常数以及CB [7]在质子酸中的独特溶解性。由于文献中报道的大多数伪轮烷以动态混合物的形式存在，并且通常很难分离，因此我们的研究代表了一个很好的例子，可以通过简单的方法获得纯的伪[n]轮烷（n = 2、3、4、5）。 “通过线程进行沉淀”方法。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号