葫芦脲的分解氧化研究

葫芦脲是高度对称的刚性分子,在试图改进Kim等氧化制取羟基葫芦脲的过程中发现,葫芦[6]脲(CB[6])在多种过硫酸盐(过硫酸钾、过硫酸钠、过硫酸胺)的氧化下,除了可以获得羟基葫芦脲外,还可以得到进一步分解产物草酸.研究表明,CB[n](n=5,7,8)及其羟基葫芦脲也存在类似的现象.这是国内外首次发现葫芦脲在进行腰位C—H键羟基化的同时,还可以进一步氧化形成草酸.     

羟基葫芦[6]脲与孟加拉红包结作用的荧光光谱研究

采用荧光光谱法研究了羟基葫芦[6]脲(HOCB[6])对孟加拉红(TSS)的包结作用,考察了HOCB[6]浓度、缓冲液pH、温度、包结时间、有机溶剂等因素对包结作用的影响,结果表明,体系的荧光强度随着HOCB[6]浓度的升高而增强,呈现显著荧光增敏现象,同时荧光峰位有一定蓝移,Hildebrand-Benesi法计算结果显示HOCB[6]与TSS形成了1∶1的包结配合物,包结反应的热力学参数表明该包结过程为自发放热过程,这可能是主客体分子之间的疏水作用与离子偶极作用所引起的。     

基于K2S2O8-KOH体系合成羟基葫芦[6]脲的研究

基于已报道的以葫芦脲-过硫酸钾体系的羟基葫芦脲合成反应,本文研究了加入KOH对原体系的影响,在优化的反应条件下,可以较理想的产率(27%)得到目标产物。产物的结构经~1H NMR、~(13)C NMR和HR-ESI-MS进行确证。     

甘脲和羟基葫芦[6]脲气相色谱固定相的制备及其色谱分离性能比较研究

甘脲是羟基葫芦[6]脲(HOCB6)的前体, 本文设计了一种在酸性条件下均匀涂渍固定液的新方法, 首次将甘脲和羟基葫芦[6]脲用作气相色谱固定相. 将甘脲和HOCB6填装成气相色谱填充柱后, 以烷烃、卤代烃、芳香烃、醇、酮、酯、酸、胺等物质为探针, 用复杂样品花露水对它们的色谱分离性能进行了比较研究. 结果表明, 甘脲和HOCB6 都是良好的气相色谱固定相, 热稳定性高, 柱性能稳定. 两种固定相对以上溶质探针都有较好的分离能力, HOCB6固定相(PSP)与甘脲固定相(GSP)相比较, 总体上具有更好的分离选择性, 对难分离的芳香族位置异构体(如二甲苯、甲基苯胺)具有良好的分离能力, 显示出较高的立体选择性, 对花露水中的高沸点组分有较好的分离效果. 上述研究也表明, 由于溶质在载气中传质比葫芦脲内腔快得多, 全包结尽管有利于提高分离选择性, 但展宽后的柱效不理想; 适当的高柱温既保留了部分包结作用, 同时存在端口协同作用, 能兼顾高选择性和高柱效.     

光谱法研究羟基葫芦[6]脲与对氨基苯磺酸的分子识别作用

光谱法研究羟基葫芦[6]脲与对氨基苯磺酸的分子识别作用;紫外光谱法;荧光光谱法;分子识别;包结作用;羟基葫芦[6]脲;对氨基苯磺酸     

荧光法研究羟基葫芦[6]脲与水溶性苯胺蓝的分子识别作用

采用荧光光谱法研究羟基葫芦[6]脲(HOCB6)与水溶性苯胺蓝(AB)、荧光素(FS)和甲基紫(MV)之间的包结作用。结果表明,HOCB6与FS和MV无相互作用,而与AB能形成1∶1型的HOCB6-AB内包结物,并测得HOCB6-AB包结物的包结常数为1.02×103L.mol-1。考察了溶液的pH值、常见有机溶剂、表面活性剂和金属离子等对该包结物的形成及荧光强度的影响,初步探讨了它们之间的作用机理。通过选用不同荧光探针作客体,揭示客体分子的大小和空间位阻对主客体包结物的形成具有决定性的影响,在空间匹配的条件下,通过疏水和氢键作用形成稳定的包结物。     

一种新型羟基葫芦[6]脲气相色谱固定相性能的研究

本文首次成功地制备和利用羟基葫芦[6]脲((HO)12CB[6])作填充柱气相色谱固定相。研究表明,羟基葫芦[6]脲固定相(PSP)具有较宽的操作柱温、高度的化学和热稳定性,对多种类型的化合物展示较高的色谱分离选择性,这包括烷烃、芳烃、醇类、酯类、酮类和胺类等多种化合物。新柱对一些二取代苯环芳族位置异构体有较强的分离能力。实验发现,羟基葫芦[6]脲固定相对日用花露水中复杂的挥发性成分有高效快速分离能力。同时,初步探讨了新固定相的色谱分离机理,发现羟基葫芦[6]脲对溶质的部分包结作用,而不是完全包结作用,有利于提高其色谱分离选择性和柱效。此外,在极速程序升温色谱中,该固定相低流失基线漂移小,有利于实现宽沸点范围复杂样品的快速气相色谱分离分析。     

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.     

pH对一锅法合成葫芦[n]脲修饰金纳米颗粒形貌影响

采用一锅法制备葫芦[n]脲(n=6,7)修饰的金纳米颗粒(Au-NPs@CB[n]),并研究了pH、温度对其尺寸的影响.通过紫外-可见-近红外(UV-Vis-NIR)光谱和透射电子显微镜(TEM)表征,证明合成了形貌规整、尺寸均一的Au-NPs@CB[n].具体表现为CB[7]修饰的Au-NPs尺寸为7?14 nm,C...     

Synthesis and binding behaviors of monomethyl cucurbit[6]uril

By reacting 3a-methylglycoluril and glycoluril with paraformaldehyde, monomethyl cucurbit[6]uril was synthesized in 14% yield. The new host molecule forms stable inclusion complexes with diamine and hexylaminocarbazole derivatives.     

Recognition of glycine by cucurbit[5]uril and cucurbit[6]uril: A comparative study of exo- and endo-binding

Recognition features of glycine (Gly) with cucurbit[5]uril (Q[5]) and cucurbit[6]uril (Q[6]) both in aqueous solution and solid state were investigated by ¹H NMR spectroscopy and X-ray crystallography. ¹H NMR data indicate that the Gly is located outside of the portals of the Q[5], exhibiting exo binding with the Q[5]. In the case of the Q[6], the Gly shows endo binding or a dual binding mode (endo and exo binding) with the host, which depends on the amount of the host in the aqueous solution. X-ray crystallography clearly display that the Gly forms 2:1 exclusion complex with the Q[5], and 2:1 inclusion complex with the Q[6]. Interestingly, hydrogen bondings between the encapsulated Gly molecules in the Q[6] were observed.     

瓜环准轮烷分子晶体结构及切割DNA研究

报道了瓜环准轮烷分子晶体结构及DNA的切割.     

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）.     

Host-Guest Interactions of Cyclopentanocucurbit[6]uril with Alkyl Imidazolium Hydrochlorides

The host-guest interactions between cyclopentanocucurbit-[6]uril(CyP₆Q[6]) as host and six alkyl imidazolium hydrochloride as guests(g1, g2, g3, g4, g5, and g6) have been studied by various techniques, such as ¹H NMR spectroscopy, isothermal titration calorimetry, mass spectrometry, and single-crystal X-ray diffraction analysis. The experimental results showed that CyP₆Q[6] formed 1:1 inclusion complexes with each of guests g1-g6. The part of the guest entered the cavity of CyP₆Q[6] changes as the alkyl chain increases in length. It can be seen that the length of the alkyl chain plays a key role in determining the mode of host-guest interactions.     

Preparation and characterization of a novel single crystal of Th(IV) with cucurbit[6]uril

One new single crystal [Th(NO₃)₂(H₂O)₆](CB₆)(NO₃)2·2H₂O was prepared using Th(NO₃)4·4H₂O and cucurbit[6]uril (CB₆) as reagents in HNO₃ aqueous solution by slow evaporation. The coordination number of Th⁴⁺ is ten. Th⁴⁺ is coordinated with six monodentate water molecules and two symmetric bidentate chelating nitrate ions, while other two nitrate ions act as the counterion anions. CB₆ is a second-sphere ligand which is hydrogen bonded to the water molecules of [Th(NO₃)₂(H₂O)₆]²⁺. Besides, there are also two free water molecules in the crystal system.     

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.