Precise Macroscopic Supramolecular Assemblies: Strategies and Applications

Macroscopic supramolecular assembly (MSA) is a new concept in supramolecular science with a focus on interfacial assembly of macroscopic building blocks, which has largely extended the applicable materials of supramolecular assembly and provided new solutions to fabricating tissue scaffolds, soft devices, etc. The precision of the assembled structures is of great interest; unlike molecular assemblies, MSA precision is highly dependent on the matching degree of assembled surfaces because of the large interactive area and group number, which result in remarkably increased kinetic possibilities and metastable assemblies. This Concept introduces the principle, history, and development of MSA, elaborates the low-precision challenge in MSA, summarizes the strategies for precise MSA based on the different thermodynamic stability of precise/imprecise structures and control over assembly kinetics, and finally demonstrates the applications of precise MSA structures in advanced manufacture such as tissue scaffolds.     

Elasticity‐Dependent Fast Underwater Adhesion Demonstrated by Macroscopic Supramolecular Assembly

Macroscopic supramolecular assembly (MSA) is a recent development in supramolecular chemistry to associate visible building blocks through non‐covalent interactions in a multivalent manner. Although various substrates (e.g. hydrogels, rigid materials) have been used, a general design rule of building blocks in MSA systems and interpretation of the assembly mechanism are lacking and are required. Herein we design three model systems with varied elastic modulus and correlated the MSA probability with the elasticity. Based on the effects of substrate deformability on multivalency, we have proposed an elastic‐modulus‐dependent rule that building blocks below a critical modulus of 2.5 MPa can achieve MSA for the used host/guest system. Moreover, this MSA rule applies well to the design of materials for fast underwater adhesion: Soft substrates (0.5 MPa) can achieve underwater adhesion within 10 s with one order of magnitude higher strength than that of rigid substrates (2.5 MPa).     

Dual‐Controlled Macroscopic Motions in a Supramolecular Hierarchical Assembly of Motor Amphiphiles

Three‐dimensional unidirectionally aligned and responsive supramolecular hierarchical assemblies have much potential in adaptive materials for biomedical and soft actuator applications. However, to achieve systematical control of the motion of stimuli‐responsive materials by orthogonal external stimuli and to complete a series of complicated tasks remains a grand challenge. Herein, we demonstrate a novel designed hybrid supramolecular assembly of molecular motor amphiphiles that also serves as a template for iron nanoparticles growth, and as a consequence this soft hybrid material is orthogonally controlled by dual light/magnetic stimuli. Macroscopic motor amphiphile strings, decorated with iron nanoparticles, provide fast response photoactuations and magnet induced movements that allows a precisely controlled cargo transport process.     

多肽超分子手性自组装与应用

多肽分子作为一类重要的生物手性小分子,能够通过分子自组装形成包括纳米螺旋、纳米管、手性凝胶等在内的有着独特生物效应和光学活性的手性纳米材料。这类材料具有易于功能化修饰的优点,在化学、生物、医药、材料科学等领域有着广泛应用,成功对多肽手性自组装结构进行精准多级调控,是进一步实现其功能化应用的基础。本文重点介绍了多肽分子氨基酸序列组成与构型等内部因素,以及溶液pH、溶剂、添加剂等外界因素对多肽分子手性自组装行为的影响,并归纳得出其关键作用机制;同时,还介绍了多肽手性自组装材料在手性催化、手性检测、模板合成、手性光学等领域的应用。     

Precise Macroscopic Supramolecular Assembly by Combining Spontaneous Locomotion Driven by the Marangoni Effect and Molecular Recognition

Macroscopic supramolecular assembly bridges fundamental research on molecular recognition and the potential applications as bulk supramolecular materials. However, challenges remain to realize stable precise assembly, which is significant for further functions. To handle this issue, the Marangoni effect is applied to achieve spontaneous locomotion of macroscopic building blocks to reach interactive distance, thus contributing to formation of ordered structures. By increasing the density of the building blocks, the driving force for assembly transforms from a hydrophobic–hydrophobic interaction to hydrophilic–hydrophilic interaction, which is favorable for introducing hydrophilic coatings with supramolecular interactive groups on matched surfaces, consequently realizing the fabrication of stable precise macroscopic supramolecular assemblies.     

环糊精超分子组装体与核酸的相互作用

环糊精是一类由6～8个D-型葡萄糖连接而成的环聚多糖分子,目前已广泛应用于化学和生物学的许多领域.综述了一些生物活性的环糊精超分子组装体,如环糊精假聚轮烷、环糊精/金纳米粒子组装体、环糊精/富勒烯组装体、环糊精/碳纳米管组装体等的构筑及其与核酸的相互作用,如对核酸的切割、凝聚、传递作用和对核酸酶的抑制作用等方面的研究进展.     

Macroscopic Assembly of Chiral Hydrogen-bonded Metal-free Supramolecular Glasses for Enhanced Color-tunable Ultralong Room Temperature Phosphorescence

Glassy materials, with desirable mechanical rigidity, shaping ability, high transparency, are attracting great interest in diverse fields. However, optically bulk molecule-based glasses are still rare, mainly due to limited monomeric species and harsh preparation conditions. Herein, we report a facile bottom-up solution fabrication process to obtain metal-free supramolecular glasses (SMGs) at the macroscopic scale using L-Histidine and hexamethylenetetramine as building blocks. The chiral SMGs possess color-tunable ultralong room temperature phosphorescence (decay lifetime up to 141.2 ms) and circular polarized luminescence (g factor up to 8.7×10⁻³). The strong hydrogen bonds effectively drive the formation of SMGs, and provide a rigid microenvironment to boost triplet exciton generation. By virtue of excitation- and temperature-dependent ultralong phosphorescence of the SMGs, applications including multicolored displays, visual UV detection, and persistently luminescent thermometer are demonstrated.     

超分子结构甲基橙插层水滑石的组装及其光热稳定性研究

甲基橙是一种酸性染料,但因为它的光和热稳定性较差,使其应用范围和使用效果受到了一定限制.以Mg_0.67Al_0.33(OH)₂(CO₃)_0.165·0.58H₂OLDHs为前体,采用离子交换法,将甲基橙插入到LDHs层间,借助XRD,FTIR,UV-Vis和TG-DTA等手段对样品进行表征.结果表明,甲基橙阴离子可以完全取代前体层间的CO₃^2-离子,组装得到晶体结构良好的甲基橙插层LDHs.对其结构进行研究发现,LDHs主体层板与客体甲基橙阴离子之间存在静电吸引、氢键和其它弱化学键相互作用,具有超分子结构特征.该超分子结构材料不仅保持了甲基橙本身的颜色,而且与甲基橙相比,其耐光性和耐热性均有大幅度的提高.     

Tetra-benzothiadiazole-based [12]Cycloparaphenylene with Bright Emission and Its Supramolecular Assembly

The radial conjugated π-system of cycloparaphenylenes (CPPs) makes them intriguing fluorophores and unique supramolecular hosts. However, the bright photoluminescence (PL) of CPPs was limited to the blue light and the supramolecular assembly behavior of large CPPs was rarely investigated. Here we present the synthesis of tetra-benzothiadiazole-based [12]cycloparaphenylene (TB[12]CPP), which exhibits a lime to orange PL with an excellent quantum yield up to 82 % in solution. The PL quantum yield of TB[12]CPP can be further improved to 98 % in polymer matrix. Benefiting from its enlarged size, TB[12]CPP can accommodate a fullerene derivative or concave–convex complexes of fullerene and buckybowl through the combined π–π and C−H⋅⋅⋅π interactions. The latter demonstrates the first case of a ternary supramolecule of CPPs.     

Synergistic Assembly of Covalent and Supramolecular Polymers

Integrating irreplaceable features of both covalent chemistry and noncovalent interactions into a single entity to maximize the applicability is highly desired. Here, a discovery of this type of hybrid, developed by Stupp and co‐workers, is developed, where a synergistic combination of covalent and noncovalent compartments enables them to assemble by each other perfectively. The covalent compartments can grow into polymer chains assisted by a supramolecular compartment. The supramolecular compartments can be reversibly removed and re‐formed to reconstitute the hybrid structure. The obtained soft materials can serve as functional platforms for molecular delivery or self‐repairing materials.

     

Supramolecular Assembly and Hybridization in Giant Nanomembranes

We demonstrated recently that large nanomembranes became available from inorganic, organic/inorganic and totally organic precursors. Spin coating of mixtures of acrylate monomers and zirconium butoxide (or tetraethoxysilane), when combined with simultaneous radical polymerization and sol-gel reaction, gave 10–30 nm thick, free-standing nanomembranes composed of metal oxides and crosslinked acrylates as interpenetrating network. This approach was extended to thermosetting resins (epoxy, melamine and phthalic resins), to fabricate robust, free-standing nanomembranes. Mechanical properties of the nanomembranes as measured by the bulge test and by a compression method were comparable to those of the corresponding macroscopic resins. The hybrid nanomembrane was subsequently prepared by supramolecular assembly of the nanofilm with surfactants and lipids. These amphiphiles produced adsorbed monolayers on the nanomembrane and some of the assemblies were stably kept in water.     

The Supramolecular Assembly of Porphyrin Arrays

The self-assembly of porphyrin arrays containing three, seven or eleven porphyrins results from the interaction of the bis-pyridyl porphyrin 1 with the zinc porphyrins 2, 3, or 4, respectively.     

Supramolecular Assembly and Chirality of Synthetic Carbohydrate Materials

Hierarchical carbohydrate architectures serve multiple roles in nature. Hardly any correlations between the carbohydrate chemical structures and the material properties are available due to the lack of standards and suitable analytic techniques. Therefore, designer carbohydrate materials remain highly unexplored, as compared to peptides and nucleic acids. A synthetic D -glucose disaccharide, DD , was chosen as a model to explore carbohydrate materials. Microcrystal electron diffraction (MicroED), optimized for oligosaccharides, revealed that DD assembled into highly crystalline left-handed helical fibers. The supramolecular architecture was correlated to the local crystal organization, allowing for the design of the enantiomeric right-handed fibers, based on the L -glucose disaccharide, LL , or flat lamellae, based on the racemic mixture. Tunable morphologies and mechanical properties suggest the potential of carbohydrate materials for nanotechnology applications.     

Synthesis and Self Assembly of Hydrogen-Bonded Supramolecular Polymers

New synthetic methodologies towards hydrogen bonded supramolecular polymers are described. Focus is directed on synthetic work towards telechelics with hydrogen bonds either as side chain moieties or as endgroups. Physical ordering effects related to polymers and particles are discussed citing own and related work in ∼60 references.     

超分子组装体在催化领域中的应用

超分子组装体的各组分规整排列、高比表面积等微纳米结构特点使其在催化应用领域中显示出独特的催化性能,成为当前研究的一个热点。本文将超分子组装体按照空间维度分为四类,对不同维度的超分子组装体在催化领域中的应用研究进行了简要综述;依据不同维度下组装体的结构特点,分别探讨了其催化机制以及应用优势,并对其今后的发展方向作了进一步的展望。     

基于环糊精构筑的镧系稀土发光超分子组装体

镧系元素由于其优异的发光特性,如长寿命的激发态、尖锐的线状发射带和较大的Stokes位移等,在发光材料中表现出极大的优势,被越来越多地应用于高级功能发光材料的设计中.而环糊精作为第二代超分子主体分子具有易于功能化修饰以及特异性结合发光客体等优势而被广泛地用于构筑发光材料、荧光传感等超分子体系.作者从基于环糊精的镧系稀土配位化合物超分子组装体的构筑出发,对不同镧系环糊精发光材料的最新研究进展进行综述,为开发构筑新型多功能化镧系发光材料提供参考.最后,提出了稀土发光材料目前所遇到的科学问题,并对基于环糊精稀土发光材料的发展方向进行了展望.     

Gemini型两亲分子超分子组装研究进展

综述了国内外对Gemini型两亲分子在超分子组装方面的研究进展。总结了Gemini分子的体相组装、界面组装以及近几年应用领域的研究进展;着重介绍了基因传递、纳米材料模板、降解剂、药物缓释以及胶凝剂的制备等方面的应用进展;对相关研究领域的主要研究成果做了一些探讨和分析;为更加深入探索和研究Gemini型两亲分子的超分子组装提供参考信息。     

Anion-Templated Assembly of a Supramolecular Cage Complex

The templating effect of the tetrafluoroborate ion leads to assembly of four Co^II ions and six bridging ligands around this anion to give a tetrahedral complex with a bridging ligand along each edge and the anion trapped in the central cavity (shown below). Surprisingly under identical conditions but with Ni^II a simpler dinuclear complex forms.