From a library of five crown ether macrocycles with different ring sizes and redox-active moieties, such as tetrathiafulvalene (TTF) and naphthalene dimiide (NDI), directional heterocircuit[3]rotaxanes were constructed. Using an axle with two binding sites with different steric accessibility, the concept of integrative self-sorting was applied to program the sequence of functional units in heteropseudo[3]rotaxanes. Depending on binding strength and ring size of the smaller macrocycles, different heteropseudo[3]rotaxane selectivities and stabilities were determined by 2D NMR spectroscopy and tandem mass spectrometry. A heteropseudo[3]rotaxane with rotaxane-like behaviour was isolated chromatographically, displaying electrochemically “frustrated” properties. A robust synthetic procedure was developed allowing the synthesis of four new hetero[3]rotaxanes incorporating specific sequences of functional units. Sequence pseudoisomeric rotaxanes which have the naphthalene diimide subunit at two different positions show distinct electrochemical properties. DFT calculations suggest that this differences could arise from a folding of the structure, in which the redox-active moieties stack with a stopper unit. This study presents a blueprint for the construction of hetero[3]rotaxanes with sequential control of the functional units along the track of the axle and paves the way to extend the functionality of mechanically interlocked molecules.

中文翻译：

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序列排序的氧化还原可切换杂[3]轮烷

从具有不同环大小和氧化还原活性部分的五个冠醚大环（如四硫富瓦烯 (TTF) 和萘二甲醚 (NDI)）组成的库中，构建了定向异质回路 [3] 轮烷。使用具有两个不同立体可及性的结合位点的轴，整合自分选的概念被应用于对杂假 [3] 轮烷中功能单元的序列进行编程。根据较小大环的结合强度和环大小，通过二维核磁共振光谱和串联质谱确定了不同的杂假 [3] 轮烷选择性和稳定性。具有类似轮烷行为的杂假 [3] 轮烷通过色谱分离，显示出电化学“受阻”特性。开发了一种稳健的合成程序，允许合成四种新的杂 [3] 轮烷，其中包含特定的功能单元序列。在两个不同位置具有萘二亚胺亚基的序列假异构轮烷显示出不同的电化学性质。DFT 计算表明，这种差异可能源于结构的折叠，其中氧化还原活性部分与停止单元堆叠。这项研究提出了构建杂[3]轮烷的蓝图，其中功能单元沿着轴的轨道顺序控制，并为扩展机械互锁分子的功能铺平了道路。在两个不同位置具有萘二亚胺亚基的序列假异构轮烷显示出不同的电化学性质。DFT 计算表明，这种差异可能源于结构的折叠，其中氧化还原活性部分与停止单元堆叠。这项研究提出了构建杂[3]轮烷的蓝图，其中功能单元沿着轴的轨道顺序控制，并为扩展机械互锁分子的功能铺平了道路。在两个不同位置具有萘二亚胺亚基的序列假异构轮烷显示出不同的电化学性质。DFT 计算表明，这种差异可能源于结构的折叠，其中氧化还原活性部分与停止单元堆叠。这项研究提出了构建杂[3]轮烷的蓝图，其中功能单元沿着轴的轨道顺序控制，并为扩展机械互锁分子的功能铺平了道路。