基于环糊精的(准)聚轮烷研究进展

环糊精聚轮烷作为超分子化学的重要成员由于可潜在应用于分子机器、组织工程支架、人体生物传感器及药物控制释放载体等智能生物材料已成为国际化学及高分子科学的一个热点.本文介绍了基于环糊精的(准)聚轮烷最新研究进展,包括(准)聚轮烷合成新方法,聚轮烷的多种类型(如嵌段型、金属软连接型、星形、pH敏感型、侧链型、聚轮烷聚集体等),以及(准)聚轮烷形成机理研究,并进一步探讨了该领域的研究前景及有待解决的问题.     

准聚轮烷的研究进展

准聚轮烷由于在刺激响应性材料、自修复材料、分子机器及荧光传感器等领域有着潜在的应用价值,近年来引起了研究人员极大的兴趣。根据准轮烷基团所处位置的不同,可将准聚轮烷分为三种类型：主链型、侧链型和其他类型 （如支化和网状准聚轮烷等）。本综述主要根据上述三种类型,基于冠醚、环糊精、杯芳烃、葫芦脲和柱芳烃这五种超分子主体分子所构筑的准聚轮烷的最新研究进展进行简要的综述,并对其未来的发展作了进一步的展望。     

生物医用类环糊精/聚合物(准)聚轮烷

环糊精及其衍生物具有“内疏水、外亲水”的特殊分子结构,可与许多客体分子包结形成包合物。利用环糊精与聚合物的包结作用构建稳定、结构可控并具有广泛应用前景的生物医用材料是材料及医学界研究的焦点之一。本文介绍了环糊精基(准)聚轮烷的概念及其组装驱动力,同时围绕由环糊精和聚合物组装形成的(准)聚轮烷在生物医用方面的研究包括药物载体(如超分子凝胶、超分子胶束、超分子纳米囊泡、药物键合(准)聚轮烷、刺激响应型(准)聚轮烷等)、基因载体、多重识别与靶向、形状记忆材料及其它相关领域工作进展作一概述。     

葫芦脲的研究进展

近几年葫芦脲和其衍生物由于其特殊的结构与性质已引起的密切关注。本文综述了葫芦脲的最新研究进展,包括葫芦脲分子及其衍生物的分子设计与合成,与聚电解质形成主链（准）聚轮烷和侧链（准）聚轮烷,与其他有机客体小分子相互作用形成轮烷和准轮烷,以及葫芦脲分子及其衍生物在囊泡、二维聚合物、色谱固定相、生物体以及药物缓释方面的最新应用。     

侧链准聚轮烷的制备及表征--葫芦脲[6]与聚[4-乙烯基-溴(N-正丁基)吡啶季铵盐]的超分子自组装

通过葫芦[6]脲(CB[6])与聚[4乙烯基溴(N正丁基)吡啶季铵盐](P4VBuBr,2)在水溶液中于室温下进行超分子自组装,得到一类超分子聚合物———准聚轮烷.通过1HNMR、IR、元素分析对其结构进行了表征,证实CB[6]位于2的侧基脂肪链上,通过非共价键与2结合,并且CB[6]与2重复单元的结合摩尔比分别为0.28∶1、0.2∶1、0.1∶1;通过X射线粉末衍射(XRD)、热重分析(TGA)、紫外可见吸收(UVVis)对其性质进行了研究,证实了准聚轮烷比相应的聚合物2有更高的热稳定性、更强的UVVis吸收以及较高的结晶能力;热分解温度随着准轮烷中CB[6]含量的增加而逐渐提高;NaBr是准聚轮烷的优良的沉淀剂.     

基于柱[n]芳烃(准)轮烷的研究进展

柱芳烃作为一类新型的大环主体分子,自2008年首次报道以来,引起了人们,特别是化学家的广泛关注.目前,它已在分子识别、(准)轮烷、超分子聚合物、分子弹簧、智能跨膜离子通道、囊泡、金属有机骨架结构等众多研究领域作为重要模块得到初步的应用.主要将以柱芳烃作为主体大环分子来构筑(准)轮烷的研究进展进行简要的综述,同时还介绍了基于柱芳烃的(准)聚轮烷的研究概况,并对未来的发展作了进一步展望.     

葫芦脲与主链聚紫精的超分子自组装制备准聚轮烷及其性质研究

通过葫芦[6]脲(CB[6])与五亚甲基聚紫精(PPeV)在水溶液中于室温下进行超分子组装,得到一种新型的准聚轮烷(PPeVCB),通过¹HNMR、元素分析、IR和X射线粉末衍射(XRD)对其结构进行了表征,证实CB[6]位于PPeV的脂肪链上,并通过非共价键与PPeV结合,且CB[6]与PPeV重复单元的结合摩尔比为1∶1;通过热重分析(TGA)、紫外-可见吸收(UV-Vis)和化学还原等方法对其性质进行了研究,证实了准聚轮烷3比相应的聚合物热稳定性更高、UV-Vis吸收和氧化能力更强.     

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.     

柱芳烃机械互锁结构的制备及功能化

柱芳烃是一类具有柱状空腔结构的大环主体,近年来逐渐成为主客体作用构筑超分子体系的重要模块之一。柱芳烃家族包含柱[5]芳烃到柱[15]芳烃等成员,其中柱[5]芳烃为热力学稳定产物,合成产率最高;其次为柱[6]芳烃。柱[5]芳烃或柱[6]芳烃可做为主体,参与构筑[1](准)轮烷、[1](准)索烃等机械自锁结构,以及[n]轮烷(n≥2)、[2]索烃、雏菊链等机械互锁结构;体系中独立分子之间存在相对运动,如轮烷中柱芳烃在轴线上可以进行穿梭运动;丰富的衍生基团赋予柱芳烃互锁结构相应的功能,如手性翻转、荧光共振能量转移、超分子凝胶、Langmuir膜、催化反应等,甚至基于柱芳烃轮烷还可构筑更复杂的树枝状分子。本文综述了柱芳烃超分子互锁体系的研究进展,详细阐述了基于柱芳烃的互锁结构的合成方法及其功能化并讨论了其在构筑分子器件及其他超分子复杂体系方面的应用前景。     

一种类似准[5]轮烷的β-胡萝卜素-β-环糊精包合物的制备与表征

用饱和溶液法在1∶1的乙醇—水体系中制备了β 胡萝卜素(β C)-β 环糊精(β CD)的准[5]轮烷超分子包合物.紫外可见光度法和元素分析均证明了4轮体的存在.FTIR、X 射线粉末衍射和1HNMR技术为轮烷超分子化合物的形成提供了有力的佐证.     

Mechanically interlocked molecules incorporating cucurbituril and their supramolecular assemblies

Mechanically interlocked molecules incorporating cucurbituril (CB[6]) as a molecular 'bead' and their supramolecular assemblies are described. An efficient synthesis of 1D, 2D and 3D polyrotaxanes with high structural regularity and molecular necklaces has been achieved by a combination of self-assembly and coordination chemistry. The functional aspects of these interlocked molecules and their supramolecular assemblies, including molecular machines and switches based on [2]rotaxanes, a 2D polyrotaxane with large cavities and channels, pseudorotaxane-terminated dendrimers, and interaction of pseudorotaxanes containing polyamines and CB[6] with DNA are also described.     

Supramolecular Mobility in Polyrotaxanes Exploits Biomedical Functions

The mobility of cyclodextrins (CDs) threaded onto a linear polymeric chain and the dethreading of the CDs from the chain are the most fascinating features seen in polyrotaxanes. These structural characteristics are very promising to their possible applications in biomedical use. Enhancing multivalent interaction between ligand-receptor systems by using ligand-polyrotaxane conjugates is one of the excellent properties related to the CD mobility. Gene delivery using cytocleavable polyrotaxanes is more practical but highly crucial in drug delivery. Such a supramolecular approach using CD-containing polyrotaxanes is extensively expected to exploit a new paradigm of advanced biomaterials for future medicines.     

Synthesis of mono-, oligo- and polyamide-cucurbituril rotaxanes

Mono-, oligo- and polyamide rotaxanes with the macrocycle cucurbituril are synthesized easily with high yields by interfacial condensation. The complex of cucurbituril with 1,6-hexanediammonium ion is used as preorganized structure. With different acid and diacid chlorides a great variety of amiderotaxanes and polyrotaxanes can be synthesized. The characterization is difficult due to the low solubility of cucurbituril and rotaxanes. But with the methods of IR, DTA, ¹H NMR and elemental analyses, the existence of the rotaxanes is shown.     

Transition metal ion directed supramolecular assembly of one- and two-dimensional polyrotaxanes incorporating cucurbituril

This paper reports a synthetic strategy to construct one- and two-dimensional (1D and 2D) polyrotaxanes, in which a number of rings are threaded onto a coordination polymer, by the combination of self-assembly and coordination chemistry. Our approach to construct polyrotaxanes with high structural regularity involves threading a cucurbituril (CB) "bead" with a short "string" to form a stable pseudorotaxane, followed by linking the pseudorotaxanes with metal ions as "linkers" to organize into a 1D or 2D polyrotaxane. A 4- or 3-pyridylmethyl group is attached to each end of 1,4-diaminobutane or 1,5-diaminopentane to produce the short "strings", which then react with the cucurbituril "bead" to form stable pseudorotaxanes. The reaction of the pseudorotaxanes with various transition metal ions including CuII, CoII, NiII, AgI, and CdII produces 1D or 2D polyrotaxanes, in which many molecular "beads" are threaded onto 1D or 2D coordination polymers as confirmed by X-ray crystallography. The overall structure of a polyrotaxane is the result of interplay among various factors that include the coordination preferences of the metal ion, spatial disposition of the donor atoms with respect to the CB beads in the pseudorotaxane, and the size and coordination ability of the counteranion.     

Multivalent interactions between lectins and supramolecular complexes: Galectin-1 and self-assembled pseudopolyrotaxanes

Supramolecular chemistry has been employed to develop flexible and adaptable multivalent neoglycoconjugates for binding galectin-1 (Gal-1). Gal-1, a dimeric lectin with two galactoside-binding sites, regulates cancer progression and immune responses. Self-assembled pseudopolyrotaxanes consisting of lactoside-displaying cyclodextrin (LCD) "beads" threaded onto polyviologen "strings" display mobile ligands as a result of cyclodextrin rotation about, and limited translation along, the polymer chain. The pseudopolyrotaxanes rapidly and efficiently precipitate Gal-1 and provide valency-corrected enhancements of up to 30-fold compared to native lactose and 20-fold over free LCD in a T-cell agglutination assay. A supramolecular statistical effect was observed, wherein the efficacy of Gal-1 inhibition correlates with the number of ligands connected to each other solely through mechanical and noncovalent interactions. Such flexible and adaptable self-assembled pseudopolyrotaxanes show promise for the study of multivalent interactions and targeting of therapeutically relevant lectins.     

Synthesis of polyrotaxanes consisting of multiple α-cyclodextrin rings threaded on reverse Pluronic PPO-PEO-PPO triblock copolymers based on block-selected inclusion complexation

New polyrotaxanes, in which multiple α-cyclodextrin (α-CD) rings were threaded and imprisoned on a reverse Pluronic PPO-PEO-PPO triblock copolymer chain and capped by two 2,4-dinitrophenyl groups at the two ends, were synthesized based on the block-selected inclusion complexation between the PPO-PEO-PPO triblock copolymers and α-CD. The polyrotaxanes were isolated and purified through size exclusion chromatography, and the chromatograms showed that the polyrotaxanes had high molecular masses as compared with their respective components. The polyrotaxanes were further characterized by using ¹³C and ¹H 1D and 2D NMR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. It was found that the threading PPO-PEO-PPO triblock copolymers became more thermally stable because they were complexed by the imprisoned α-CD. The studies demonstrated that the numbers of α-CD rings imprisoned in the polyrotaxanes were directly related to the PEO block length, rather than to the PPO block length. In all the three polyrotaxanes synthesized in this work, the central PEO block was fully covered and complexed by α-CD stoichiometrically, while the flanking PPO bocks remained free and uncomplexed. Therefore, the new polyrotaxanes took a PPO-polyrotaxane-PPO triblock architecture. The polyrotaxanes with such block architecture may be interesting supramolecular precursor for designing novel functional materials.     

季铵化聚4-乙烯吡啶衍生物与葫芦脲[6]的超分子自组装及性质研究

通过葫芦[6]脲(CB[6])与季铵化聚4-乙烯吡啶衍生物2在水溶液中于室温下进行超分子组装, 得到一种新型的超分子聚合物3, 并通过¹H NMR, IR, 元素分析, X射线粉末衍射分析(XRD)对其结构进行了表征, 证实CB[6]位于2的侧基脂肪链上, 通过非共价键与2结合; 通过热重分析(TGA)、紫外-可见吸收(UV-vis)对其性质进行了研究, 证实了超分子聚合物3比相应的聚合物2有更高的热稳定性, 以及更强的UV-vis吸收.     

Cucurbiturils–a New Family of Host Molecules

The supramolecular chemistry of cucurbituril, a synthetic receptor, is fascinating because of the remarkable guest binding behavior of the host. Although cucurbituril is potentially as useful as crown ethers, cyclodextrins, and calixarenes in many applications, its chemistry has not been developed much until recently because of several shortcomings. Recently we synthesized cucurbituril homologues and derivatives. These new members of the cucurbituril family have expanded the scope further, and interest in them has grown enormously. The diversity in guest binding behavior has led to many interesting studies such as redox control of guest binding, stabilization of charge-transfer complexes inside the host cavity, encapsulation of drug molecules, formation of redox-controllable vesicles, and so on. The cucurbituril homologues and derivatives thus provide new opportunities in many areas of supramolecular chemistry including recognition, catalysis, separation, transport, and many others.