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首页> 外文期刊>Chemistry: A European journal >Versatile Self-Complexing Compounds Based on Covalently Linked Donor-Acceptor Cyclophanes
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Versatile Self-Complexing Compounds Based on Covalently Linked Donor-Acceptor Cyclophanes

机译：基于共价连接的供体-受体环的环糊精的多功能自络合物

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摘要

A range of covalently linked donor-acceptor compounds which contain 1)a hydroquinone(HQ)unit,2)a 1,5-dioxynaphthalene(DNP)ring system,or 3)a tetrathiafulvalene(TTF)unit as the pi-donor,and 4)cyclobis(paraquat-p-phenylene)(CBPQT~(4+))as the it-accepting tetracalpha-tionic cyclophane were prepared and shown to operate as simple molecular machines.The pi-donating arms can be included inside the cyclophane in an intramolecular fashion by virtue of stabilizing noncovalent bonding interactions.What amounts to self-complex-ing/decomplexing equilibria were shown to be highly temperature dependent when the it-donating arm contains either an HQ or DNP moiety.The thermodynamic parameters associ-ated with the equilibria have been unraveled by using variable-temperature ~1H NMR spectroscopy.The negative DELTAH~deg and DELTAS~deg values account for the fact that the "uncomplexed" conformation becomes the dominant species,since the entropy gain associated with the decomplexation process overcomes the enthalpy loss resulting from the breaking of the donor-acceptor interactions.The arm's in-and-out movements with respect to the linked cyclo-phanes can be arrested by installing a bulky substituent at the end of the arm.In the case of compounds carrying a DNP ring system in their side arm,two diastereoisomeric,self-complexing conformations are observed below 272 K in hexadeuterioacetone.By contrast,control over the TTF-containing arm's movement is more or less ineffective through the thermally sensitive equilibrium although it can be realized by chemical and electrochemical ways as a result of TTF's excellent redox properties.Such self-complexing compounds could find applications as thermo-and electroswitches.In addition,the thermochromism associated with the arm's movement could lead to some of the compounds finding uses as imaging and sensing materials.
机译：一系列共价连接的供体-受体化合物，其包含1）对苯二酚（HQ）单元，2）1,5-二氧萘（DNP）环系统或3）四硫富瓦烯（TTF）单元作为pi-供体，和4）制备了环双（百草枯-对苯撑）（CBPQT〜（4+）），它是可以接受的四环α-型环烷，并显示其可作为简单的分子机器操作。通过稳定的非共价键相互作用，分子间的方式表现出来。当它的给体臂包含HQ或DNP部分时，相当于自复合/解复合的平衡是高度依赖于温度的。通过可变温度〜1H NMR光谱可以消除平衡。负DELTAH〜deg和DELTAS〜deg值说明“未复合”构象成为主要物质，因为与复合分解过程相关的熵增益得以克服的由于破坏了供体与受体之间的相互作用而产生的焓损失，可以通过在臂的末端安装一个庞大的取代基来阻止臂相对于连接的环-phanes的进出运动。在侧臂中有一个DNP环系统，在272 K以下在六氘丙酮中观察到两个非对映异构体，自复杂的构象。相反，尽管可以实现，但通过热敏平衡来控制含TTF的臂的运动或多或少是无效的。由于TTF具有出色的氧化还原特性，因此可以通过化学和电化学方法进行研究。此类自复合化合物可以用作热电开关和电开关。此外，与手臂运动相关的热致变色现象可能导致某些化合物被用作成像和热电偶。感应材料。

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