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首页> 外文期刊>Chemistry: A European journal >Dual-Mode 'Co-Conformational' Switching in Catenanes Incorporating Bipyridinium and Dialkylammonium Recognition Sites
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Dual-Mode 'Co-Conformational' Switching in Catenanes Incorporating Bipyridinium and Dialkylammonium Recognition Sites

机译：包含联吡啶和二烷基铵识别位点的链烷烃的双模式“共构象”转换

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摘要

Three [2]catenanes and three [3]catenanes incorporating one or two #pi#-electron-rich macrocyclic polyethers and one #pi#-electron-deficient polycationic cyclophane have been synthesized in yields ranging from 4 to 38%.The #pi#-electron-rich macrocyclic components possess either two 1,4-dioxybenzene or two 1,5-dioxynaphthalene recognition sites.The #pi#-electron-deficient cyclophane components incorporate two bipyridinium and either one or two dialcylammonium recognition sites.The template-directed syntheses of these catenanes rely on i) #pi#…#pi# stacking interactions between the dioxyarene and bipyridinium recognition sites,ii) C-H…O hydrogen bonds between some of the bipyridinium hydrogen atoms and some of the polyether oxygen atoms,and iii) C-H…#pi# interactions between some of the dioxyarene hydrogen atoms and the aromatic spacers separating the bipyridinium units.The six catenanes were characterized by mass spectrometry and by both ~1H and ~13C NMR spectroscopy.The absorption spectra and the electrochemical properties of the catenanes have been investigated and compared with those exhibited by the component macrocycles and by related known catenanes.Broad and weak absorption bands in the visible region,originatng from charge-transrer(CT) interactions between electron-do-nor and electron-acceptor umits,have been observed.Such charge-transfer interactions are responsible for the quenching of the potentially fluorescent excited states of the aromatic units of the macrocyclic polyether components.The redox behavior of these novel compounds has been investigated and correlations among the observed redox potentials are illustrated and discussed.The catenanes undergo co-conformation switching upon one-electron reduction of the two bopyridinium units.One of them—in its reduced form—can be also switched by acid/base inputs and exhibits AND logic behaviof.The co-conformational rearrangements induced by the redox and acid/base stimulations lend themselves to exploitation in the development of molecular-level machines and logic gates.
机译：合成了三种[2]邻苯二酚和三种[3]邻苯二酚，其中掺入一种或两种＃pi＃电子电子大环聚醚和一种＃pi＃电子缺乏电子的聚阳离子环烷，产率为4％到38％。富电子电子的大环成分具有两个1,4-二氧苯或两个1,5-二氧萘识别位点。缺乏电子的环戊烯成分包含两个联吡啶和一个或两个拨号环cy识别位点。这些链烯的直接合成依赖于：i）双氧芳烃与联吡啶鎓识别位点之间的堆积反应; ii）一些联吡啶氢原子与一些聚醚氧原子之间的CH…O氢键，以及iii ）某些双氧芳烃氢原子与分隔双吡啶鎓单元的芳族间隔基之间的CH…＃pi＃相互作用。通过质谱，〜1H和〜13C NMR光谱对六个链烷进行了表征。已经研究了链烯的ctra和电化学性质，并将其与组分大环化合物和相关的已知链烯所显示的那些进行了比较。可见区中的宽吸收带和弱吸收带，起因于电子与电子之间的电荷-电子互感器（CT）相互作用这种电荷转移相互作用是大环聚醚组分芳香单元潜在的荧光激发态猝灭的原因。已经研究了这些新型化合物的氧化还原行为，并研究了它们之间的相关性。对两个联吡啶单元进行单电子还原后，连环发生共构转换。其中之一（还原形式）还可以通过酸/碱输入进行切换，并表现出“与”逻辑行为氧化还原和酸/碱刺激引起的共构象重排使其易于开发在分子级机器和逻辑门的开发中。

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