Versatile Self-Complexing Compounds Based on Covalently Linked Donor-Acceptor Cyclophanes
作者:Yi Liu、Amar H. Flood、Ross M. Moskowitz、J. Fraser Stoddart
DOI:10.1002/chem.200400614
日期:2005.1
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
一系列共价连接的供体-受体化合物,包含1)对苯二酚(HQ)单元,2)1,5-二氧萘(DNP)环系统或3)噻吩富勒烯(TTF)单元作为pi-供体,和4)制备了作为pi接受的四阳离子环烷的环双(百草枯-对亚苯基)(CBPQT(4+)),并显示其可作为简单的分子机器操作。可以通过稳定非共价键相互作用以分子内方式将pi供体臂包括在环烷内。当pi供体臂包含HQ或DNP部分时,表明自复合/解复合平衡的程度与温度高度相关。已通过使用可变温度(1)H NMR光谱图阐明了与平衡相关的热力学参数。负DeltaH度和DeltaS度值说明了以下事实:“未复合”构象成为主要物质,因为与复合过程相关的熵增益克服了由于供体-受体相互作用破坏而产生的焓损失。可以通过在臂的末端安装庞大的取代基来阻止臂相对于连接的环戊烯的进出运动。在化合物的侧臂带有DNP环系统的情况下,在六氘代丙酮中,在272 K以下观察到两个非对映异构体