• 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 synthesis of calix[6]tmpa: A new calix[6]azacryptand with unique conformational and host-guest properties
【24h】

Efficient synthesis of calix[6]tmpa: A new calix[6]azacryptand with unique conformational and host-guest properties

机译：杯[6] tmpa的高效合成：一种新的杯[6]氮杂密码子，具有独特的构象和来宾特性

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

A new C-3v-symmetrical calix[6]azacryptand, that is, calix[6]tmpa (11), was synthesized by efficient [1+1] macrocyclization reactions. Remarkably, both linear and convergent synthetic strategies that were applied lead to equally good overall yields. Calix[6]tmpa behaves as a single proton sponge and appeared reluctant to undergo polyprotonation, unlike classical tris(2-pyridylmethyl)amine (tmpa) derivatives. It also acts as a good host for ammonium ions. Interestingly, it strongly binds a sodium ion and a neutral guest molecule, such as a urea, an amide, or an alcohol, in a cooperative way. A H-1 NMR study indicated that the ligand, as well as its complexes, adopt a major flattened cone conformation that is the opposite of that observed with the previously reported calix[6]cryptands. Characterization of the monoprotonated derivative 11(.)H(+) by X-ray diffraction also revealed the presence of a 1,3-alternate conformation, which is the first example of its kind in the calix[6]arene family. This conformer is probably also present in solution as a minor species. The important covalent constraint induced by the polyaromatic tmpa cap on the calixarene skeleton, and conversely from the calix core onto the tmpa moiety, is the likely basis for the unique conformational and chemical properties of this host.
机译：通过高效的[1 + 1]大环化反应合成了新的C-3v对称杯[6]氮杂密码子，即杯[6] tmpa（11）。值得注意的是，采用线性和会聚的合成策略均会产生同样好的总产量。与经典的三（2-吡啶基甲基）胺（tmpa）衍生物不同，杯杯[6] tmpa表现为单个质子海绵，似乎不愿进行多质子化。它也是铵离子的良好宿主。有趣的是，它以协作的方式牢固地结合了钠离子和中性客体分子，例如尿素，酰胺或醇。一项H-1 NMR研究表明，该配体及其配合物均采用主要的扁平圆锥构象，与先前报道的杯[6] cryptands观察到的相反。通过X射线衍射对单质子化衍生物11（。）H（+）进行表征，还发现了1,3-交替构象的存在，这是其在杯[6]芳烃家族中的第一个例子。该构象异构体也可能以次要形式存在于溶液中。由杯芳烃骨架上的多芳族tmpa帽诱导的重要共价约束，以及相反地从杯芳烃核心到tmpa部分，是该宿主独特构象和化学性质的可能基础。

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