H_(2)O_(2)增敏羧甲基取代benzo[3]uril电化学发光识别琥珀酰胆碱

电化学发光技术是一种高灵敏、快响应的化学分析手段。通过考察羧甲基取代benzo[3]uril的电化学发光机理,发现超氧自由基有助其电化学发光。因此,引入共反应试剂H_(2)O_(2)以达到增强羧甲基取代benzo[3]uril时所产生的电化学发光信号的目的,成功构建H_(2)O_(2)增敏羧甲基取代benzo[3]uril的电化学发光传感器用于对琥珀酰胆碱的高灵敏性进行检测,检出限低至1.0×10^(-15)mol/L。

复合材料Cucurbit[6]uril/CdS-MoS_(2)吸附性能的研究

以硫代乙酰胺,氯化镉,钼酸钠和有机大分子六元瓜环(cucunbit[6]uril,Q[6])为原料,采用水热法在200℃反应24小时合成CdS-MoS_(2)和Q[6]/CdS-MoS_(2)。利用FT-IR、XRD、XPS、SEM和UV-Vis等手段对产物结构、形貌和光学等性质进行表征,并考察CdS-MoS_(2)和Q[6]/CdS-MoS_(2)复合吸附剂对次甲基蓝的吸附作用。结果表明,CdS-MoS_(2)和Q[6]/CdS-MoS_(2)形成了花团状形貌,使其表面积较大,吸附面积增加,对次甲基蓝表现出较高的吸附量和脱色率,吸附符合准二级动力学模型。

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

A new cucurbit[6]uril bridsed binuclear complex {[Gd（H2O）6]2[Q6（H2O）]}C16·4H2O, where Q6 represents cucurbit[6]uril, has been synthesized and characterized by X-ray diffraction. The crystal structure shows that the complex has an extended cucurbit[6]uril-bridged structure consisting of two gadolinium（Ⅲ） ions, in which each gadolinium（Ⅲ） ion is coordinated with two neighboring carbonylic oxygen atoms of Q6 and six oxygen atoms of water molecules that leans toward one side of the portal. One disordered guest water molecule resides in the Q6 molecule cavity and occupies two different positions. Hydrogen bonds assemble the complcx to threedimensional supramolecular structure.

Characterization and Visible Light Photocatalytic Activity of Cucurbit[n]urils/CdS-MoS_(2)

In order to reduce the impact of CdS photogenerated electron-hole recombination on its photocatalytic performance,a narrow band gap semiconductor MoS_(2) and organic macromolecular cucurbit[n]urils(Q[n])were used to modify CdS.Q[n]/CdS-MoS_(2)(n=6,7,8)composite photocatalysts were synthesized by hydrothermal method.Infrared spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,field emission scanning electron microscopy,ultraviolet-visible and photoluminescence spectrum were used to characterize the structure,morphology and optical properties of the products,and the catalytic degradation of the solutions of methylene blue,rhodamine B and crystal violet by Q[n]/CdS-MoS_(2) composite catalyst was investigated.The results showed that the Q[n]played a regulatory role on the growth and crystallization of CdS-MoS_(2) particles,Q[n]/CdS-MoS_(2)(n=6,7,8)formed flower clusters with petal-like leaves,the flower clusters of petal-like leaves increased the surface area and active sites of the catalyst,the Q[n]/CdS-MoS_(2) barrier width decreased,the electron-hole pair separation efficiency was improved in the Q[6]/Cds-MoS_(2).Q[n]makes the electron-hole pair to obtain better separation and migration.The Q[6]/CdS-MoS_(2) and Q[7]/CdS-MoS2 have good photocatalytic activity for methylene blue,and the catalytic process is based on hydroxyl radical principle.

Cucurbit[n]uril-based nanostructure construction and modification

New fabrication method of nanostructures is of great importance for the applications of nanoscience and nanotechnology.This review summarizes cucurbit[n]uril(CB[n])-based nanostructure fabrication and modification approaches.These strategies include the use of CB[n]s as building blocks and supramolecular crosslinkers to fabricate nanostructures,to surface modify nanostructures,and as gatekeepers to control the release of encapsulated cargo.These nanostructures are used for drug delivery,bioimaging,chemical sensing,catalysis and other applications.CB[n]s often play a vital role in the fabrication of these nanos-tructures,and the realization of the applications.

Cucurbit[8]uril-mediated multi-color fluorescence system for time-dependent information encryption

Programming microscopic assembly mode to control macroscopic property is an attractive research objective.In particular,controlling molecular assembly to control fluorescence is of considerable interest for developing smart fluorescent materials.Herein,a color-tunable supramolecular emissive system was developed based on cucurbit[8]uril mediated host-guest assembly.Chemical designing for the molecular structures with minimized change resulted in different assembly modes and hence generating distinctive fluorescence,including green,yellow and orange with the addition of cucurbit[n]uril.Taking advantage of this feature,the advanced information encryption material(4D code)with multiple encryption levels and time-dependent encryption feature was developed.Such a code was dynamic on time scale,generating a series of 3D codes with time.The encrypted information only can be recognized by integrating time-coursed codes.This work provides a new insight for designing intelligent fluorescent materials for information encryption with high level of security.

Photoisomerization,assembling and fluorescence photoswitching behaviors of a water-soluble stiff-stilbene with cucurbit[7]uril

Photoresponsive supramolecular systems have merited extensive attention for their applications in materials science and life science.Here,we synthesized a water-soluble stiff-stilbene molecular photoswitch,exhibiting outstanding photoisomerization reaction between its(E)-and(Z)-configurations upon irradiation at distinct light.The photoswitch can assemble with cucurbit[7]uril(CB[7])to form a superior fluorescent supramolecular complex(compared to the only guest)with excellent water solubility,which manifested dramatic photoluminescence enhancement caused by restriction of intramolecular rotation and remained good photochromic characteristics.Furthermore,introduction of CB[7]influence photoreaction quantum yield(Φ)of the stiff-stilbene,leading to reduction ofΦ_(E→Z) and increase ofΦ_(Z→E) of the stiff-stilbene.Importantly,the photoadjustable supramolecular assembly can act as a fluorescence switch,and the phototunable guest further selectively modulate G-quadruplex structure of Tel22 upon light irradiation or with addition of CB[7].The study provides a new simple way for accurately regulating photochromic properties of molecular switches and developing smart materials with potential applications in controlled modulation of G-quadruplex,targeted biological imaging and so on.

Double-cavity nor-seco-cucurbit[10]uril-based supramolecular assembly for selective detection and removal of trinitrophenol

The effective removal and selective detection of explosive and toxic pollutant trinitrophenol (TNP) is an attractive but challenging field.Herein,a double-cavity nor-seco-cucurbit[10]uril (ns-Q[10])-based supramolecular assembly 8-HQ@ns-Q[10]was fabricated and its structure was characterized by X-ray single crystal diffraction.In this assembly,the stoichiometric ratio of ns-Q[10]and 8-hydroxyquinoline (8-HQ) is 1:2,which is also attributed to the special double-cavity structure of ns-Q[10].The luminescence sensing experiments showed that 8-HQ@ns-Q[10]can be used as a good fluorescence-enhanced sensing material (enhanced 27-fold) for the rapid detection of explosives and the aqueous contaminant TNP,with a limit of detection (LOD) of 2.07×10^(-5)mol/L,without interference from other phenolic compounds.Furthermore,TNP can be efficiently removed in the presence of assembly 8-HQ@ns-Q[10],and the removal efficiency is more than 89%.Therefore,the supramolecular assembly 8-HQ@ns-Q[10],as a fluorescenceenhanced luminescence sensor and adsorption material,has rich research value and potential application prospect when applied to the detection and removal of TNP in aqueous environment.

Supramolecular assemblies of cucurbit[n]urils and 4-aminopyridine controlled by cucurbit[n]uril size(n=5,6,7 and 8)

The binding interactions between 4-aminopyridine(4-AP) and a series of cucurbit[n]urils(Q[5], Q[6],TMe Q[6], Q[7], Q[8]) have been studied using1H NMR spectroscopy, UV–vis absorption spectroscopy,isothermal titration calorimetry(ITC) and X-ray crystallography. The data indicates that the Q[5]@4-AP complex exhibits exo binding, which is not observed in the other four host-guest complexes. Furthermore,X-ray crystallography clearly reveals how the Q[n]s bind with 4-AP to form complexes, for example Q[5]forms an outer-surface complex, whilst Q[6], TMe Q[6] and Q[7] formed 1:1 host and guest type complexes, and Q[8] formed a stable 1:2 ternary complex due to its large cavity, which can accommodate two 4-AP molecules.

Hierarchically structured flower-like Ru nanoparticles-cucurbit[6]uril/multiwalled carbon nanotubes as efficient pH-universal hydrogen evolution electrocatalyst

Developing efficient and stable electrocatalyst to hydrogen evolution reaction adaptable for electrolytes with different p H is a big challenge.In this work,a hierarchically structured ternary nanohybrid composed of flower-like Ru nanoparticles,rigid macrocyclic cucurbit[6]uril(CB[6])and carboxylated multiwalled carbon nanotubes(MWCNTs)was successfully prepared by chemical wet method.Benefited by the structural merits of flower-like Ru nanoparticles exposed abundant active sites supported by the MWCNTs holding superior mass transport and electrons transfer ability as well as the existence of CB[6],the obtained catalyst exhibited outstanding HER activities with overpotentials of 27,37 and 70 m V at-10 m A/cm^(2) in alkaline,acidic,and neutral electrolytes,respectively.Under the same electrocatalytic operation conditions,the HER performance is comparable or superior to commercial Pt/C catalyst(47,27and 49 m V).Besides,chronopotentiometric and accelerated stability test also revealed its extraordinary stability,which could be further employed for electrocatalytic procedure in a broad pH range.

[5]Rotaxane, linear polymer and supramolecular organic framework constructed by nor-seco-cucurbit[10]uril-based ternary complexation

Here we use nor-seco-cucurbit[10]uril(ns-CB[10]) based ternary complexation to construct [5]rotaxane,linear supramolecular dynamic rotaxane polymers and cubic 3D supramolecular organic framework.A [5]rotaxane is constructed by ns-CB[10], TMe CB[6] and short linear derivatives of 4,4'-bipyridinium(M2). ns-CB[10], CB[7] and long linear derivatives of 4,4'-bipyridinium(M3) self-assemble into a linear supramolecular dynamic rotaxane polymer. ns-CB[10] and tetracationic tetrahedral monomer selfassemble and form a three-dimensional supramolecular organic framework. The above results demonstrate that ns-CB[10]-based ternary complexation is a versatile platform to build various supramolecular systems.

Electrochemical detection of amino acids based on cucurbit[7]uril-mediated three-dimensional gold nanoassemblies

In this paper, cucurbit[7]uril(CB[7])-mediated three-dimensional gold nanoassemblies were successfully prepared to increase the loaded amount of CB[7] and enhance the electrochemical detection of amino acids. Particle sizes of gold nanoparticles(Au NPs) significantly affect stability and detection sensitivity of nanoassemblies. The volume of gold nanoassemblies first increased and then decreased with the increase of CB[7] concentration. The 3D gold nanoassemblies composed of 16 nm Au NPs and 100 μmol/L CB[7]had excellent stability and maximum volume, exhibiting more sensitive detection for a variety of amino acids. And the detection limits of aromatic amino acids are lower in virtue of the higher binding constant between aromatic amino acids and CB[7]. This study will develop and deepen our understanding of molecular recognition in amino acids detection.

A novel pillar[5]arene-cucurbit[10]uril based host-guest complex: Synthesis, characterization and detection of paraquat

The macrocyclic family comprising pillar[n]arenes and cucurbit[n]urils have received much attention recently. However, studies on the construction of supramolecular complexes formed directly with derivatized pillar[n]arenes and cucurbit[n]urils are scant. Given the interest in such systems, herein we have synthesized a new type of naphthalene-derivatized pillar[n]arene NTP5 and selected Q[10] as the host molecule. The 4-[2-(1-naphthalenyl)ethenyl]pyridine of NTP5 is encapsulated by Q[10] and formed a hostguest complex in water-acetic acid(1:1) solution accompanied by enhanced fluorescence, which changed the morphology of NTP5 from a sphere to a porous form. In addition, the fluorescence of Q[10]-NTP5 can be quenched by the addition of the highly toxic pesticide paraquat(PQ), and the mechanism was shown to be the formation of a new charge transfer ternary system of Q[10]-NTP5-PQ. This work provides new ideas for the contribution of supramolecular assemblies based on derivatized pillar[n]arenes and their combination with cucurbit[n]urils and reveals their potential applications.

Structural characteristics and the label-free detection of poly(3,4-ethylenedioxythiophene/cucurbit[7]uril)pseudorotaxane at single molecule level

A multi-technique approach to prove the preparation of poly(3,4-ethylenedioxythiophene/cucurbit[7]uril)pseudorotaxanes(PEDOT∙CB7-PPs)is reported.Molecular docking simulation and matrix-assisted laser desorption/ionization mass spectrometry(MALDI MS)validate the complexation ability of the CB7 molecule towards 3,4-ethylenedioxythiophene(EDOT),which leads to the EDOT∙CB7 inclusion complex.Oxidative polymerization of EDOT∙CB7 enabled the synthesis of PEDOT∙CB7-PPs.The water-soluble part of PEDOT∙CB7-PPs was selected,freeze-dried,and chemically characterized.Furthermore,dynamic light scattering(DLS)has been used to study the particle size and z-potential(ZP-ζ)of PEDOT∙CB7-PPs.The ZP-ζvalue(35 mV)evidenced that the PEDOT∙CB7-PPs formed stable water dispersion.By combining the emerging nanopore resistive pulse sensing technique(Np-RPS)and computational modeling,we identified strong interactions of PEDOT∙CB7-PPs with the aerolysin(Ael)nanopore.PEDOT∙CB7-PPs behave as positive charged species,and thus trans negative bias promotes its interactions with the Ael nanopore.The computational modeling results are fully consistent with the Np-RPS detection,which also reveals strong interactions between PEDOT∙CB7-PPs and the Ael nanopore.With this study,we hope to provide new insights and a better understanding of the interactions between supramolecular complexes based on CB7 and biological entities,which is instrumental for future applications in the field of nanobiotechnology.

Supramolecular Self-assembly Formed from Cucurbit[8]uril and p-Hydroxybenzoic Acid

The binding behavior of cucurbit[8]uril(Q[8])and p-hydroxybenzoic acid(p-HBA)has been investigated using ^(1)H NMR titration experiments,UV-Vis absorption,isothermal titration calorimetry(ITC),and X-ray crystallography.Results revealed that the Q[8]can accommodate two p-HBA molecules to form a 1:2 host-guest inclusion complex in solution,namely(p-HBA)2@Q[8].From a poorly scattering crystal,we were able to identify two symmetry unique Q[8]rings,but with different p-HBA fillings.The structure can be represented as Q[8]+1.5 p-HBA,which gives Q[8]@(p-HBA)2∙Q[8]@p-HBA as the structural formula.This supramolecular structure was screened for its ability to capture iodine.The experimental results showed that the adsorption efficiency of the supramolecular organic framework material for iodine capture was 43.8%,with an equilibrium adsorption capacity of 223.3 mg/g.

Study on the Host-Guest Interactions Between Tetramethyl Cucurbit[6]uril and Benzimidazole Derivatives

In this paper,^(1)H NMR spectroscopy,isothermal titration calorimetry,X-ray crystallography and other characterization methods were used to investigate the interaction modes of tetramethyl cucurbit[6]uril(TMeQ[6])and three benzimidazole derivatives in an aqueous solution-solid state.The results showed that the aromatic ring moieties in the three derivatives all entered the cavity of TMeQ[6]and their substituents were located at the port of TMeQ[6],forming 1:1 host-guest inclusion complexes.The crystal structures showed that the aromatic part of the benzimidazole derivatives interacted with the cavity of TMeQ[6]via hydrogen bond interactions and the N atoms on the benzimidazole ring formed hydrogen bonds with the carbonyl oxygen of TMeQ[6].The ion-dipole interactions between[ZnCl_(4)]^(2-)and TMeQ[6]formed supramolecular self-assembly entities.

Controllable fabrication of a supramolecular polymer incorporating twisted cucurbit[14]uril and cucurbit[8]uril via self-sorting

A linear supramolecular polymer with controllable features based on twisted cucurbit[14]uril(tQ[14])and cucurbit[8]uril(Q[8])was firstly fabricated via an effective self-sorting strategy.Herein we designed a monomer,1–butyl–1?-(naphthalen-2-ylmethyl)-4,4?-bipyridinium bromide(BNB),that contains bipyridyl,aliphatic butyl and aromatic naphthyl groups,simultaneously.Two host molecules,tQ[14]and Q[8]were employed to develop an effective strategy for constructing a linear supramolecular polymer with con-trollable features.The alkyl groups on both sides of BNB could insert into the two cavities of tQ[14],the naphthyl part of BNB viaπ-πstacking in Q[8]cavity,serving as the driving force for supramolecular polymerization.Through self-sorting of the monomer,tQ[14]and Q[8],led to the formation of the linear supramolecular polymer.Depolymerization could be achieved by addition of adamantane hydrochloride(AH)which driven two BNB guest molecules out of the Q[8]cavity.This self-sorting strategy has great potential,not only for designing supramolecular polymer materials with different controllable structures through introduction of multiple functional groups,but also for broadening the application of twisted cucurbit[14]uril in supramolecular chemistry.

Q[6]-PW_(12)自组装体制备及其催化合成乙酸乙酯

以六元瓜环(Q[6])及Keggin型磷钨酸(PW_(12))为原料,制备Q[6]-PW_(12)自组装体。将Q[6]-PW_(12)自组装体作为催化剂应用于乙酸与乙醇酯化反应合成乙酸乙酯。结果表明,Q[6]与PW_(12)发生了自组装作用,且Q[6]-PW_(12)自组装体具有多孔结构特征;Q[6]-PW_(12)自组装体对酯化反应合成乙酸乙酯具有催化作用,且自组装体催化剂经过多次循环使用后依然效果良好。

蒙药额尔敦-乌日勒修复骨关节炎大鼠模型的机制

背景:传统蒙医临床应用蒙药额尔敦-乌日勒治疗骨关节炎的疗效肯定,但其治疗作用及相关机制尚不明确。目的:观察蒙药额尔敦-乌日勒对大鼠骨关节炎的修复过程,分析其作用机制。方法:将30只8周龄SD大鼠,采用单侧膝关节腔内注射碘乙酸钠溶液建立骨关节炎模型。造模2周后,采用随机数字表法将大鼠分为3组:对照组(6只)灌胃给予生理盐水,低、高剂量组(各12只)分别灌胃给予蒙药额尔敦-乌日勒1.4,2 g,3次/d。连续给药2,4周后,取大鼠血液样本、关节软骨及关节周围骨质,检测软骨代谢标志物(软骨寡聚基质蛋白、蛋白聚糖)、骨代谢标志物(骨碱性磷酸酶、硫酸盐角蛋白)、炎性标志物(白细胞介素6、肿瘤坏死因子α)、脂代谢标志物(总胆固醇、三酰甘油)等相关因子的变化,同时进行病理组织学观察。结果与结论:①给药2,4周后的qRT-PCR检测结果显示,与对照组比较,低、高剂量组大鼠膝关节软骨组织中寡聚基质蛋白、蛋白聚糖及关节周围骨质中骨碱性磷酸酶、硫酸盐角蛋白的mRNA表达均显著降低(P<0.05,P<0.01,P<0.001),其中以高剂量组降低更显著;②给药2,4周后,与对照组比较,低、高剂量组大鼠血清肿瘤坏死因子α、白细胞介素6水平降低(P<0.01,P<0.001),总胆固醇、三酰甘油水平升高(P<0.05,P<0.01,P<0.001),其中以高剂量组改善更显著;③苏木精-伊红染色显示,对照组大鼠膝关节软骨组织表层有较大缺损区,组织结构不明,炎症细胞浸润严重;低剂量组给药2周后大鼠膝关节软骨表面粗糙,细胞排列紊乱,软骨结构改善不明显,给药4周后大鼠膝关节软骨炎性细胞减少,结构有所恢复;高剂量组给药2周后大鼠膝关节软骨组织结构较清晰,炎症明显减轻,给药4周后大鼠膝关节软骨组织结构更清晰;④结果表明,蒙药额尔敦-乌日勒有较好的抗炎及改善软骨代谢等功效,对大鼠骨关节炎有明显的改善作用。