环糊精包合作用诱导聚合物自组装的研究进展

将主客体识别与聚合物自组装相结合,利用环糊精对聚合物的包合作用在溶液中诱导聚合物组装形成结构可控的纳米粒子,形成有别于基于环糊精/聚合物包合作用形成的结晶粉末和超分子水凝胶的新型材料.本文介绍了这种诱导组装方案的研究背景及最新的研究成果,综述了诱导组装的原理、特点及影响因素.研究表明,由这种方案制备的聚合物纳米粒子具有超分子动态可逆的特征,进而显示出对温度和pH等敏感的性质.该类环糊精包合作用诱导组装的聚合物超分子聚集体在生物医学材料方面具有潜在的应用价值,如用作药物和基因的可控传递释放载体.     

环糊精超分子水凝胶*

本文综述了近年来基于环糊精包合作用的超分子水凝胶的研究进展,主要包括：环糊精与线性、星型、接枝、超支化聚合物包合形成的多聚(准)轮烷自组装制备超分子物理凝胶及功能化多聚(准)轮烷经交联反应制备超分子化学凝胶;环糊精、环糊精二聚体及其水溶性聚合物与带疏水性侧基的聚合物经“锁-钥匙”包合作用形成超分子物理凝胶;及其在药物、基因释放载体与组织工程支架中的应用。着重介绍了剪切、温度、pH值、光等刺激-响应性超分子水凝胶的设计与制备。     

基于环糊精包合作用的大分子网络研究进展

环糊精与客体分子的“锁一钥匙”包合作用,是一种纯粹的分子间非共价键作用力,利用这一超分子作用力可以构筑大分子网络体系。基于环糊精分子的包合选择性、可调控性等优势,该缔合体系在过去十多年里备受人们关注,已成为大分子组装研究的热点。本文对这种基于环糊精包合作用的分子间包结缔合型大分子网络的最新进展进行了综述,主要包括：（1...     

环糊精聚合物与苯醌的分子包合作用及其在酶电极中的应用

研究了水溶性环糊精预聚合物的存在对苯醌/氢醌体系在铂电极上氧化还原行为的影响, 根据伏安曲线讨论了该预聚合物与苯醌的分子包合作用。环糊精预聚合物与戊二醛缩聚反应而形成的不溶性聚合物膜用于葡萄糖氧化酶的固定化, 以制得新型的第二代葡萄糖电极。由于分子包合作用, 作为电子受体的苯醌在含酶的环糊精聚合物膜中具有较高的浓度, 从而加速了固定化酶的电子传递。测定了酶电极上BQ反应的动力学参数。     

基于环糊精主客体包合作用构筑的聚合物

在由超分子作用构筑聚合物的研究中,环糊精因能与多种客体分子形成超分子包合物而被广泛应用。本文根据超分子构筑单元的不同,综述了两类基于环糊精主客体包合作用的聚合物:(1)通过具有环糊精及客体基团的大分子间的包合构筑的非共价键嵌段聚合物,包括不同拓扑结构聚合物的制备及其功能化;(2)通过客体基团修饰环糊精的相互包合构筑的超分子聚合物,主要涉及高聚合度超分子聚合物的制备及其研究进展。     

环糊精超分子聚合物在药物/基因递送载体领域的研究进展

超分子聚合物通常以非共价键作为构筑驱动力,其结构具有动态可逆的特点,在新型响应性聚合物材料中具有突出优势。环糊精可通过主客体识别作用与客体分子如二茂铁、偶氮苯、金刚烷、苯环等形成包合,以此构筑的超分子组装体展现出丰富的自组装-解组装特性、刺激响应性、较低的细胞毒性和较好的生物相容性,有望在药物/基因载体领域得到应用。本文从环糊精超分子聚合物的生物医用出发,着重对近年来环糊精超分子聚合物载体在药物控制释放、基因转染以及药物/基因共递送三方面的研究进展进行了总结和评述,并在此基础上展望了环糊精超分子聚合物的研究方向和发展趋势。     

α-环糊精包合物中环己烷构象平衡的PM3研究

用PM3分子轨道方法研究了α-环糊精的包合作用对环己烷构象平衡的影响。发现α-环糊精的包合作用可以改变环己烷的构象平衡。计算结果表明,虽然环己烷的椅式构象比船式构象稳定18.5 kJ*mol-1, 但在α-环糊精的包合物中,船式环己烷包合物比椅式环己烷包合物稳定4.4 kJ*mol-1。因此,超分子体系中客体分子的构象平衡不能简单地从其游离态的构象平衡外推得到,而应该考虑在超分子体系中分子间相互作用对构象的影响。     

环糊精聚合物的分子包合作用及在酶电极中的应用

伏安法用于研究环糊精预聚合物的分子包合作用．红外光谱实验表明环糊精预聚合物与戊二醛缩聚生成的聚合物带有悬挂的羰基,后者能使葡萄糖氧化酶共价固定化．由于分子包合作用,电子受体可存储在含酶的环糊精聚合物膜中,从而提高了酶膜中电子受体的浓度又减少了电子受体的用量．用ＴＴＦ等作电子受体,可实现酶和电子受体在环糊精聚合物中的同时固定化．环糊精聚合物膜中的组成和膜厚度可以控制,为酶电极的基础研究工作提供了方便．     

基于环糊精包结络合作用的大分子自组装

本文综述了基于环糊精包结络合作用的大分子自组装的研究进展,包括：（1) 线型、梳型、多臂星型或超支化聚合物与环糊精或其二聚体自组装形成多聚轮烷（分子项链）、多聚准轮烷、双多聚（准）轮烷、分子管、双分子管、超分子凝胶及其应用;（2）桥联环糊精与桥联客体分子自组装制备线型或超支化超分子聚合物;（3）温度、pH值、光及客体分子刺激响应智能体系; （4) 通过亲水性的环糊精线型均聚物与含金刚烷的疏水性聚合物之间的包结络合作用来制备高分子胶束及其空心球等。     

β-环糊精聚合物与取代水杨酸、3-羟基-2-萘甲酸超分子配合物的构筑及其电流变性能

从化学设计的观点出发, 研究了环糊精聚合物形成超分子配合物的性能. 采用“固相自组装技术”合成了6种β-环糊精聚合物(β-CDP)与取代水杨酸及3-羟基-2-萘甲酸的超分子配合物, 并利用NMR, FT-IR, UV-vis和荧光分析等技术对形成超分子配合物的组成和结构进行了表征. 分别采用所合成的超分子配合物与二甲基硅油配制了电流变液. 在4 kV/mm的直流电场作用下, 超分子配合物较β-CDP电流变活性提高了34%~72%, 且以β-CDP/3-羟基-2-萘甲酸超分子配合物电流变液的屈服应力为最高, 可达9.8 kPa; 同时发现, 变更不同客体分子也可对超分子配合物电流变材料的流变效应起到调节作用, 当水杨酸苯环上含有其他取代基时, 取代基的位置及其数量对相应超分子配合物电流变液的力学响应性具有微调节作用, 并由材料的介电性能测试得到证实.     

Assembly behavior of inclusion complexes of beta-cyclodextrin with 4-hydroxyazobenzene and 4-aminoazobenzene

To further reveal the factors governing the supramolecular assembly of beta-cyclodextrin (beta-CD) inclusion complexes, two aggregates (1 and 2) were prepared from the inclusion complexes of beta-CD with 4-hydroxyazobenzene and 4-aminoazobenzene, respectively, and their binding behavior were investigated by means of X-ray analysis, UV-vis, NMR, and circular dichroism spectra in both solution and the solid state. The obtained results indicated that the beta-CD/4-hydroxyazobenzene complex 1 could form head-to-head dimers (triclinic system, space group P1) in the solid state, which were further self-assembled to a linear supramolecular architecture by the intra- and interdimer hydrogen bond interactions as well as the intradimer pi-pi interactions. However, when the included guest 4-hydroxyazobenzene was switched to a 4-aminoazobenzene, the resultant beta-CD/4-aminoazobenzene complex 2 (monoclinic system, space group P2(1)) could be self-assembled to a wave-type supramolecular aggregate under similar conditions. Furthermore, the combination of crystallographic and spectral investigations jointly revealed the inclusion complexation geometry of beta-CD with 4-hydroxyazobenzene and 4-aminoazobenzene in both solution and the solid state, which demonstrated that the disparity of substituents in the azobenzenes played an important role in the inclusion complexation and molecular assembly, affecting not only the structural features of aggregates but also the binding abilities of azobenzenes with beta-CD.     

Supramolecular polymers fabricated by orthogonal self-assembly based on multiple hydrogen bonding and macrocyclic host–guest interactions

Supramolecular polymers constructed by orthogonal self-assembly based on multiple hydrogen bonding and macrocyclic host-guest interactions have received increasing attention due to their elegant structures,outstanding properties,and potential applications.Hydrogen bonding endows these supramolecular polymers with good adaptability and reversibility,while macrocyclic host-guest interactions give them good selectivity and versatile stimuli-responsiveness.Therefore,functional supramolecular polymers fabricated by these two highly specific,noninterfering interactions in an orthogonal way have shown wide applications in the fields of molecular machines,electronics,soft materials,etc.In this review,we discuss the recent advances of functional supramolecular polymers fabricated by orthogonal self-assembly based on multiple hydroge n bonding and host-guest interactions.In particular,we focus on crown ether-and pillar[n]arene-based supramolecular polymers due to their compatibility with multiple hydrogen bonds in organic solution.The fabrication strategies,interesting properties,and potential applications of these advanced supramolecular materials are mainly concerned.     

PREPARATION AND CHARACTERIZATION OF INCLUSION COMPLEXES OF TWO-ARM LINEAR AND FOUR-ARM STAR-SHAPED POLY（ε-CAPROLACTONE）S WITH α-CYCLODEXTRIN

Both four-ann star-shaped poly（ε-caprolactone） （4sPCL） and two-ann linear PCL （2LPCL） were synthesized and their inclusion complexation with α-cyclodextrin （α-CD） were studied. The inclusion complexes （ICs） formed between the PCL polymers and α-CD were characterized by ^1H-NMR, DSC, TGA, WAXD, and FT-1R, respectively. Both branch ann number and molecular weight of the PCL polymers have apparent effect on the stoichiometry （CL：CD, mol：mol） of these ICs. All these analytical results indicate that the branch arms of the PCL polymers are incorporated into the hydrophobic α-CD cavities and their original crystalline properties are completely suppressed. Moreover, the inclusion complexation between two-ann linear or four-ann star-shaped PCL polymers and α-CD not only enhances the thermal stability of the guest PCL polymers but also improves that of α-CD.     

Near-Infrared-Emissive Self-assembled Polymers <Emphasis Type="Italic">via</Emphasis> the Implementation of Molecular Tweezer/Guest Complexation on a Supramolecular Coordination Complex Platform

Coordination-driven self-assembly strategy has demonstrated the efficiency and versatility to construct well-ordered supramolecular coordination complexes (SCCs) such as discrete metallacycles and metallacages.In recent years,it has aroused tremendous interest to build more complexed self-assembled structures via the implementation of additional non-covalent recognition motifs on the SCCs platform.In this work,we have successfully attained this objective,with the elaborate manipulation of non-interfering pyridine-Pt2+and molecular tweezer/guest complexation in a hierarchical self-assembly manner.The resulting SCCs-based linear supramolecular polymers exhibit intriguing NIR-emissive behaviors,primarily attributed to the presence of intermolecular Pt(Ⅱ)-Pt(Ⅱ) metal-metal interactions in the non-covalent tweezering structure.Hence,supramolecular engineering of multiple non-covalent interactions offers a feasible avenue toward functional materials with tailored properties.     

Self-assembling polysaccharide systems based on cyclodextrin complexation: Synthesis,properties and potential applications in the biomaterials field

The supramolecular assemblies based on polysaccharides modified by cyclodextrins (CDs) and/or hydrophobic guest molecules have inspired interesting developments in the biomedical, pharmaceutical and cosmetic fields. This review will update the recent progress in the design, synthesis and study of such supramolecular structures. Preliminary studies demonstrated that such systems, based on the physical cross-linking of biopolymers through CD inclusion complexation, have potential as injectable hydrogels for the controlled release of drugs. Their nanoscale association also lead to the formation of original particles and films which pave the way to new applications in drug delivery and tissue engineering.     

A systems approach to controlling supramolecular architecture and emergent solution properties via host-guest complexation in water

The assembly behavior of aryl/alkyl imidazolium ionic liquid salts in aqueous solution has been investigated. These salts undergo self-assembly into one-dimensional stacks via hydrophobic and π-π interactions upon increasing concentration, which led to a substantial increase in the solution viscosity in water. Addition of the macrocyclic host molecules cucurbit[n]urils (CB[n]) were found to effectively alter the supramolecular assemblies, as evidenced from the dramatic increase (by CB[7]) and decrease (by CB[8]) in solution viscosity and aggregation size in water, on account of the different binding stoichiometries, 1:1 complexation with CB[7] and 2:1 complexation with CB[8]. Furthermore, the aggregate architectures were controllably modified by competitive guests for the CB[n] hosts. This complex supramolecular systems approach has tremendous implications in the fields of molecular sensor design, nonlinear viscosity modification, and controlled release of target molecules from a defined supramolecular scaffold in water.     

Recent Progress in Azobenzene-Based Supramolecular Materials and Applications

Azobenzene-containing small molecules and polymers are functional photoswitchable molecules to form supramolecular nanomaterials for various applications. Recently, supramolecular nanomaterials have received enormous attention in material science because of their simple bottom-up synthesis approach, understandable mechanisms and structural features, and batch-to-batch reproducibility. Azobenzene is a light-responsive functional moiety in the molecular design of small molecules and polymers and is used to switch the photophysical properties of supramolecular nanomaterials. Herein, we review the latest literature on supramolecular nano- and micro-materials formed from azobenzene-containing small molecules and polymers through the combinatorial effect of weak molecular interactions. Different classes including complex coacervates, host-guest systems, co-assembled, and self-assembled supramolecular materials, where azobenzene is an essential moiety in small molecules, and photophysical properties are discussed. Afterward, azobenzene-containing polymers-based supramolecular photoresponsive materials formed through the host-guest approach, polymerization-induced self-assembly, and post-polymerization assembly techniques are highlighted. In addition to this, the applications of photoswitchable supramolecular materials in pH sensing, and CO₂ capture are presented. In the end, the conclusion and future perspective of azobenzene-based supramolecular materials for molecular assembly design, and applications are given.     

Cyclodextrin-based inclusion complexation bridging supramolecular chemistry and macromolecular self-assembly

Research into macromolecular self-assembly has been progressively developing since the 1970s but with a little affect from the achievements of supramolecular chemistry. In recent years, this situation has changed as more and more factors and concepts in supramolecular chemistry have been introduced into studies of the self-assembly of polymers. In this respect, inclusion complexation based on cyclodextrins plays a remarkable role. In this tutorial review, we address how inclusion complexation has been employed and used to promote the recent developments in macromolecular self-assembly. These include the amphiphilicity adjustment of macromolecules, non-covalent linkages for forming pseudo block copolymers and micelles, surface modification and functionalization of polymeric micelles and vesicles, and the combination of synthetic polymeric assemblies with biological moieties. Furthermore, the realization of the reversible stimuli-responsiveness of polymeric assemblies and materials, particularly hydrogels by means of controllable inclusion complexation is discussed as well.     

Fluorocarbon associative polymers

Fluorocarbon associative polymers modified along the backbone or at the extremities by hydrophobic groups are reviewed with respect to their association and rheological properties in aqueous solutions. Above a threshold concentration corresponding to the formation of a reversible network structure, the solutions behave as physical gels. In this review, it is shown that the viscoelasticity of fluorocarbon associative polymer gels is enhanced with respect to that of hydrocarbon analogues. For polymers substituted at the extremities (telechelics), significant progresses have been made in recent years concerning the microstructure, the phase behavior and the rheology of the gel state. Telechelics in solutions are forming multiconnected structures, which dynamical features are in good agreement with those of transient network models.