紫精与八元瓜环的超分子组装及光切割质粒DNA

利用紫精可以活化水中溶解氧的特性, 设计合成了苯-紫精化合物(BEV). 利用紫外吸收、电化学及核磁等方法研究了BEV与八元瓜环CB[8] 之间的相互作用. 实验结果表明, 2种化合物可以进行主客体超分子自组装形成1∶ 1的二元包合物BEV-CB[8]. 同时, 分别考察了化合物BEV和BEV-CB[8]与小牛胸腺DNA的相互作用, 并采用琼脂糖凝胶电泳研究了氙灯光照下化合物对pBR322 DNA的切割能力. 结果表明, CB[8]的引入改变了化合物BEV与DNA的作用方式, 使嵌入作用和静电作用增强. 光照结果说明只有超分子BEV-CB[8]在光照下可以完全切割质粒DNA, 即CB[8]的存在明显提高了BEV对质粒DNA的切割效率.     

钡离子驱动荧光准轮烷

含有水溶性季铵盐基团的4-正己氨基-1,8-萘酰亚胺化合物在水中与葫芦脲[6]通过疏水及氢键作用形成准轮烷结构,而且体系荧光波长红移了17nm,荧光强度降低32%.研究表明,往准轮烷溶液中加入与葫芦脲[6]具有强结合力的Ba2+离子会使准轮烷结构离解,体系荧光恢复;而再往溶液中加入SO42-,Ba2+以BaSO4沉淀的形式被除去,这时准轮烷又重新生成.核磁氢谱、紫外-可见吸收光谱、荧光光谱和荧光寿命对体系的结合/离解过程的研究表明这种结合/离解过程是可逆的.本体系可以模拟插头/插座的连接和断开动作.     

准轮烷/轮烷在药物载体中的应用

准轮烷/轮烷是超分子化学领域内的一类重要成员,其结构可在外界刺激下发生改变,这一特点使其在分子机器制备方面取得了广泛的应用。近年来,由于其结构的特殊性,在药物载体领域也开始引起人们的关注。本文对近十年来准轮烷/轮烷在药物载体领域内的发展情况进行了综述,重点概述准轮烷修饰的硅纳米粒子和主体-轮烷这两类药物载体的发展历程以及各自的优缺点,最后展望了准轮烷/轮烷在药物载体领域的发展方向。     

新型双核铜配合物的结构及DNA切割活性

合成了一种以吡啶-2,6-二甲酸(dipicH2)桥联的新型双核邻菲咯啉铜配合物，[Cu₂(phen)₃(dipic)(OH)]·Na·ClO₄·2H₂O(phen 为1，10-菲咯啉的缩写)。该配合物晶体属于单斜晶系，P2₁/n空间群，a=1.225 85(2) nm，b=2.196 3(3) nm，c=1.619 5(2) nm，β=100.951(2)°。配合物分子中的两个中心铜离子均处于变形的四方锥配位环境，并通过吡啶-2，6-二甲酸配体上的氧氮原子相连。凝胶电泳结果表明，在pH 7.4，温度37 ℃，以抗坏血酸为还原剂或在H₂O₂的存在下，该配合物对超螺旋pBR322 DNA表现出显著的切割活性，为人工金属核酸酶的研究提供了新的例证。     

准轮烷和轮烷研究新进展

准轮烷和轮烷是一个在超分子化学中非常活跃的新领域.它们具有的特殊结构决定了准轮烷和轮烷在纳米功能材料和分子机器等方面有很大的应用潜力,因此倍受化学家们的关注.根据形成轮烷和准轮烷时主要驱动力的不同,可将轮烷和准轮烷的制备方法分为统计学缠绕、化学转移、受氢键驱动、受亲水-疏水相互作用驱动、受金属配位作用驱动、和受π-π堆积相互作用以及电荷转移驱动等.本文分别从上述几种驱动力的角度综述了近年来准轮烷和轮烷在合成和应用方面的最新研究进展.     

插销式分子器件——可利用酸碱调控的超分子准轮烷

含有吗啉的富π电子苯醚链化合物与缺π电子联吡啶环玢CPQT通过分子间的π-π堆积作用形成超分子准轮烷结构。研究发现,随着温度的变化,该准轮烷结构的相对运动速度加快,弱相互作用减弱;并进一步发现,随着酸和碱的依次加入,该准轮烷结构呈现"开"与"关"的"插销式"器件性能。     

含有葫芦[6]脲的新型准轮烷的合成

通过葫芦[6]脲(CB[6])与两个质子化的1,4-丁二胺在水溶液中于室温下进行超分子自组装, 得到一种新型的准轮烷. 通过¹H NMR, 质谱和¹H ROESY NMR对其结构进行了表征, 证实CB[6]位于质子化1,4-丁二胺的脂肪链上, 通过非共价键与1,4-丁二胺结合, 并且主体(CB[6])与客体的结合的物质的量之比为2∶1.     

可调控准轮烷的合成和开关性能的研究

二苯醚;核磁共振;分子开关;可调控准轮烷的合成和开关性能的研究     

可利用酸碱调控的分子器件富——电子二苯醚客体和缺电子联吡啶大环组成的准轮烷的“开”与“关”

利用π-π堆积作用,富电子4,4′-二氨基二苯醚(A)和4,4′-二羟基二苯醚(B)分别与缺电子联吡啶大环(CPQT)自组装成准轮烷A-CPQT和B-CPQT;利用酸碱调控准轮烷A-CPQT的“开”与“关”,此过程可利用体系的核磁共振氢谱的化学位移变化进行跟踪.     

含羟基环多胺金属配合体系切割DNA及其体外抗肿瘤活性研究

研究了3-羟基-1,5,8-三氮杂环癸烷(L1)和3,13-二羟基-1,5,8,11,15,18-六氮杂二十元环胺(L2)与Ni(Ⅱ),Ca(Ⅱ),Co(Ⅱ),Cu(Ⅱ)离子在不同配比下与质粒pBR322DNA及肝癌细胞BEL-7402的相互作用情况.发现L1的单核体系和L2的双核体系能有效地将超螺旋DNA同时切割得到切口开环型和线型DNA,并对BEL-7402表现出明显的生长抑制作用.     

A twin-axial[5]pseudorotaxane based on cucurbit[8]uril and a-cyclodextrin

A twin-axial hetero[5]pseudorotaxane was constructed based on 1-hexyl-4,40-bipyridinium guest 1 and cucurbit[8]uril（CB[8]）and a-cyclodextrin（a-CD）.In its structure,CB[8]included two bipyridinium units to realize the twin-axial mode,and the hexyl chain was threaded into the cavity of a-CD.The[5]pseudorotaxane contains two types of macrocyclic hosts while the single axial and twin axial modes co-exist in its structure.The transformation of[5]pseudorotaxane could be realized by the addition of acid and 2,6-dihydroxynaphthalene（HN）.     

Coordination of Bimuth(III) to Cucurbit[8]uril. Preparation and X‐ray Structure of [{Bi(NO3)(H2O)5}2(Q8)][Bi(NO3)3(H2O)4]2[Bi(NO3)5]2·Q8·19H2O

Bi(NO₃)₃ reacts with cucurbit[8]uril, (Q8), in 3M HNO₃ to give the title complex whose structure includes three discrete Bi complexes: [{Bi(NO₃)(H₂O)₅}₂(Q8)]⁴⁺ (CN of Bi = 9, both NO₃^— and cucurbit[8]uril are bidentate), [Bi(NO₃)₅]^2— (CN of Bi = 10, all NO₃^— are bidentate), and [Bi(NO₃)₃(H₂O)₄] (CN of Bi = 10, all NO₃^— are bidentate).     

Cucurbit[5]uril derivatives as oxygen carriers

ABSTRACT

Cucurbit[n]urils are rigid cage-molecules of pumpkin-like shape, made of n-glycoluril units, able to bind mainly neutral molecules and cations. In this work, we investigate the binding of three cucurbit[5]uril derivatives with dioxygen O₂ and show that one of them, namely per-hydroxylated cucurbit[5]uril, (OH)₁₀CB[5], is able to significantly bind dioxygen gas at physiological temperature, even in the presence of sodium chloride at the concentration of injectable solution in blood. As cucurbit[n]urils studied up to now reveal low toxicity, per-hydroxylated cucurbit[5]uril appears as a promising precursor to design a host able to transport O₂ in a haemoglobin substitute solution.     

Cucurbit[6]uril nanocavity as an enhanced spectrofluorimetric method for the determination of pyrene

The effect of the addition of macrocyclic host cucurbit[6]uril (CB6) on the photophysical properties of polycyclic aromatic hydrocarbon pyrene (PYR) was analyzed. The fluorescence emission spectra of the aromatic compound were determined at 25.0 °C in different acidic media (HCl 18%, w/v, or HCOOH 55%, w/v) with and without CB6. A significant enhancement in the fluorescence signals in the presence of CB6 was observed. The average values of the association constant (K_A) for the 1:1 stoichiometry complex and the relative fluorescence quantum yield ratio between the complexed and free PYR (?^PYR–CB6/?^PYR) in acidic media were (4.0 ± 0.5) × 10² M⁻¹ and (5.7 ± 0.2), respectively.The analytical parameters improved in the presence of CB6. The relative decrease in the limit of detection was 92%. The matrix effect was evaluated in fortified samples of tap water and tea extracts. Apparent recoveries obtained by the proposed method in tap water and tea extracts were (82–103)% and (89–99)%, respectively. Selectivity studies with inorganic and organic species were performed. The method is rapid, direct, selective and simple.     

[5]Rotaxane and [5]Pseudorotaxane Based on Cucurbit[6]uril and Anchored to a Meso-tetraphenyl Porphyrin

Water soluble [5]rotaxane and [5]pseudorotaxane based on cucurbit[6]uril and anchored to a meso-tetraphenyl porphyrin have been synthesized and characterized by spectroscopic methods (¹H-NMR, ¹³C-NMR and UV), and by elemental analysis, and mass spectrometry. The preliminary results of the pH-driven switching properties of [5]rotaxane investigated through ¹H-NMR spectroscopy are reported. These results were compared with those obtained from a model porphyrin, which was prepared by the de-threading cucurbit[6]uril from [5]pseudorotaxane under basic conditions.Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

Synthesis and Crystal Structure of a Binuclear Gadolinium(III) Complex Bridged by Cucurbit[6]uril

Cucurbit[6]uril (Q6, Figure 1) is a macrocyclic ligand with interesting complexing properties. In contrast to other macrocyclic ligands, such as crown ethers, cryptands or calixarenes, this ligand has a rigid structure offering a hollow core of about 5.5 …