通过离散数量的环双环(百草枯)的穿线,制备了五种供体-受体低聚轮烷,它们由四甘醇链组成的哑铃组成,散布着三个和五个1,5-二氧萘单元,并被2,6-二异丙基苯氧基封端终止。 -对-亚苯基)环,然后进行依赖于点击化学反应的动力学控制的封堵方案。在五种低聚轮烷的最终动力学控制的模板导向合成过程中,采用了著名的铜(I)催化的炔-叠氮环在位于聚醚链末端的叠氮化物官能团与带有炔的塞子前体之间的环加成反应。随后1氘代乙腈中低温(233 K)的1 H NMR光谱。通过与哑铃和环组分的光谱比较,揭示了五种低聚轮烷的二级结构和构象。通过关注从广泛的低温光谱获得的一些关键探针质子化学位移的变化,可以看到五种低聚紫杉烷中的四种低聚紫杉烷的哑铃状质子在哑铃的质子内发生高度折叠的情况。被C的组合第五oligorotaxane表示在对照化合物的效果,带来环中缺乏π电子的联吡啶单元与哑铃中富含π电子的1,5-二氧萘单元
Structural Fine-Tuning of (−Donor−<i>s</i><i>pacer</i>−acceptor−<i>s</i><i>pacer</i>−)<i><sub>n</sub></i> Type Foldamers. Effect of Spacer Segment Length, Temperature, and Metal-Ion Complexation on the Folding Process
作者:Suhrit Ghosh、S. Ramakrishnan
DOI:10.1021/ma0478759
日期:2005.2.1
structures by virtue of intrachain charge-transfer interactions between the adjacent donor and acceptor units. Comparison of the proton NMR and UV−visible spectra of the three different polymers clearly reveals that PDA–4OE, which has the shortest tetra(oxyethylene) spacer, exhibits the greatest propensity to fold in the nascent form. A significant upfield shift of the aromatic protons upon lowering of temperature
据报道,一系列聚合物(PDA - n OE)的合成包含富电子的(供体)和电子不足的(受体)芳族单元的交替排列,它们通过柔性的低聚(氧乙烯)(n OE)间隔基连接。寡(氧乙烯)间隔基的长度从四(氧乙烯)(n = 4)到六(氧乙烯)(n = 6)有所不同,以检查这些聚合物通过链内电荷形成折叠结构的相对倾向,转移相邻供体和受体单元之间的相互作用。三种不同聚合物的质子NMR和UV可见光谱的比较清楚地表明PDA – 4OE具有最短的四(氧乙烯)间隔基的化合物,以新生形式表现出最大的折叠倾向。降低温度后,芳族质子的显着高场转移证实了PDA – 4OE折叠的更大趋势。另一方面,具有较长间隔基的聚合物的光谱显示出非常弱的温度依赖性,表明它们以新生形式折叠时很迟钝。但是,在合适的碱金属离子(或极性溶剂)存在下,具有较长的低聚(氧乙烯)间隔基的聚合物的光谱也表现出更强的温度依赖性(类似于P D A – 4OE
Donor–Acceptor [2]‐ and [3]Catenanes Assembled from Versatile Pre‐Organized Cp*Rh/Ir‐Directed Pseudorotaxane Tectons
作者:Dong Liu、Ye Lu、Yue‐Jian Lin、Guo‐Xin Jin
DOI:10.1002/chem.201904082
日期:2019.11.22
synthesize [2]- and [3]catenanes. Firstly, binuclear Cp*Rh/Ir-directed (Cp*=pentamethylcyclopentadienyl) pseudorotaxanes were prepared through self-assembly, driven by donor-acceptor interactions between electron-deficient naphthalenediimide (NDI) units and an electron-rich crownether. Subsequently, the pre-organized pseudorotaxanes were applied as tectons for self-assembly of [2]- and [3]catenanes by combination
作者:Ken D. Johnstone、Kentaro Yamaguchi、Maxwell J. Gunter
DOI:10.1039/b506987d
日期:——
The design and chemical synthesis of a series of hybrid flexible self-assembling supramolecules utilising both crown ether–naphthalene diimide host–guest chemistry and metalloporphyrin–pyridyl coordination is discussed. The resulting compound structures and dynamics are probed using a variety of techniques, including diffusion ordered NMR spectroscopy (DOSY) and cold-spray ionisation mass spectrometry (CSI-MS).
A Catenated Strut in a Catenated Metal-Organic Framework
作者:Qiaowei Li、Chi-Hau Sue、Subhadeep Basu、Alexander K. Shveyd、Wenyu Zhang、Gokhan Barin、Lei Fang、Amy A. Sarjeant、J. Fraser Stoddart、Omar M. Yaghi
DOI:10.1002/anie.201003221
日期:2010.9.10
interlocked molecules (MIMs), in the form of donor–acceptor [2]catenane‐containing struts of exceptional length, have been incorporated into a three‐dimensional catenatedmetal–organicframework (MOF) at precise locations and with uniform relative orientations. Catenation is expressed simultaneously within the struts and the framework.
ring, which is capable of displaying planar chirality, and the axiallychiral binaphthol (BINAP) moiety (as both enantiomers and as the racemic modification), in a crown ether, in addition to the CBPQT4+ cyclophane—have been synthesized using a template-directed protocol. Dynamic 1H NMR spectroscopy shows that (i) the presence of immutable axialchirality, arising from the BINAP moiety in the crown