• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Dynamic Chirality: Keen Selection in the Face of Stereochemical Diversity in Mechanically Bonded Compounds
【24h】

Dynamic Chirality: Keen Selection in the Face of Stereochemical Diversity in Mechanically Bonded Compounds

机译：动态手性：面对机械键合化合物中立体化学多样性的敏锐选择

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

The template-directed syntheses, employing bisphenylene-[34]crown-10 (BPP34C10), 1,5-di-naphthoparaphenylene-[36]crown-10 (1/5NPPP36C10), and 1,5-dinaphtho-[38]crown-10 (1/5DNP38C10) as templates, of three [2]catenanes, whereby one of the two bipyridinium units in cyclobis(paraquat-p-phenylene) is replacaed by a bipicolinium unit, are described. The crude reaction mixtures comprising the [2]catenanes all contain slightly more of the homologous [3]catenanes, wherein a "dimeric" octacationic cyclophane has the crown ether macrocycles encircling the alternating bipyridinium units with the bipicolinium units completely unfettered. X-ray crystallography, performed on all three [2]catenanes and two of the three [3]catenanes reveals co-conformational and stereochemical preferences that are stark and pronounced. Both the [3]catenanes crystallize as mixtures of diastereoisomers on account of the axial chirality associated with the picolinium units in the solid state. Dynamic ~1H NMR spectroscopy is employed to probe in solution the relative energy barriers for rotations by the phenylene and pyridinium component of the [2]catenanes. Where there are co-conformational changes that are stereochemistry "allowed", crown ether circumrotation and rocking processes are also investigated for the relative rates of their occurrence. The outcome is one whereby the three [2]catenanes containing BPP34C10, 1/5NPPP36C10, and 1/5DP38C10 exist as one major enantiomeric pair of diastereoisomers amongst two, four, and eight diastereoisomeric pars of enantiomers, respectively. The diastereoisomerism is a consequence of the presence of axial chirality together with helical and/or planar chirality in the same interlocked molecule. These [2]catenanes constitute a rich reserve of new stereochemical types that might be tapped for their switching and mechanical properties.
机译：模板指导的合成，使用双亚苯基-[34] crown-10（BPP34C10），1,5-二萘对亚苯基-[36] crown-10（1 / 5NPPP36C10）和1,5-二萘并-[38] crown描述了三种[2]邻苯二酚的-10（1 / 5DNP38C10）作为模板，其中环双（百草枯-对亚苯基）中的两个联吡啶单元之一被联吡啶吡啶单元代替。包含[2]儿茶酚的粗制反应混合物全部含有略多的同源[3]儿茶酚，其中“二聚”八酰基环烷具有冠状醚大环，其环绕交替的双吡啶鎓单元，而双吡啶鎓单元完全不受约束。对所有三个[2]邻苯二酚和三个[3]邻苯二酚中的两个进行X射线晶体学分析，发现其共构象和立体化学偏好明显而明显。由于与固态的吡啶鎓单元相关的轴向手性，这两种[3]邻苯二酚都结晶为非对映异构体的混合物。动态〜1H NMR光谱用于在溶液中探测[2]邻苯二甲撑亚苯基和吡啶鎓组分旋转的相对能垒。在存在立体化学“允许”的共构象变化的地方，还研究了冠醚的旋转和摇摆过程，以了解它们的相对发生率。结果是一种结果，其中包含BPP34C10、1 / 5NPPP36C10和1 / 5DP38C10的三个[2]邻苯二酚在两个，四个和八个对映异构体对中分别以一对主要的非对映异构体形式存在。非对映异构是相同手性分子中存在轴向手性以及螺旋和/或平面手性的结果。这些[2] catenanes构成了丰富的新立体化学类型储备，这些新的立体化学类型可能因其开关和机械性能而得到开发。

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