Ionic Supramolecular Assemblies

Supramolecular structures assembled via noncovalent interactions have found diverse applications in mechanical, biological, electronic, and manufacturing-related fields. Ionic interactions represent key noncovalent interactions, which can be used, for example, to create highly ordered, responsive, conductive, reversible, and/or viscoelastic supramolecular assemblies. The recent advances in the field of ionic supramolecular assemblies, including those prepared from polymers, small molecules, or a combination of the two are reviewed. The versatility and simplicity of constructing ionic supramolecular assemblies are illustrated through several examples. Finally, the outstanding issues and potential opportunities are discussed to stimulate critical discussions and encourage further discovery.     

1,3-偶极环加成反应在含能材料中的应用

1,3-偶极环加成反应,被誉为点击化学的精华,在含能材料合成中有着广泛应用.文中主要介绍了其在含能黏合剂、含能盐、基团修饰、含能聚合物等方面的应用.     

Rotaxane Assemblies with Dendritic Architecture

Strategies towards the synthesis of well‐defined, mechanically interlocked, dendritic assemblies of rotaxanes are developed, one using a divergent, and the other a convergent approach. For the first time covalent bonds are not directly involved in the branching of dendrimers, only mechanical bonds act as unique branching elements.     

Stabilized Copper(I) Oxide Nanoparticles Catalyze Azide‐Alkyne Click Reactions in Water

A novel form of polyvinylpyrrolidone (PVP) coated copper(I) oxide nanoparticle (Cu₂O‐NP) was prepared and used to catalyze azide‐alkyne click reactions in water under aerobic conditions. The nanoparticles were well dispersed in aqueous solutions and have a size of 20±10 nm, as determined by transmission electron microscope (TEM). Inductively coupled plasma (ICP), X‐ray powder diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS) analyses demonstrated that the main content of Cu₂O‐NP is copper(I). The cytotoxicity of it was evaluated by an in vitro 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and its catalytic efficiency for azide‐alkyne click reactions was studied in water and organic solvents at physiological temperatures. Our results indicate that Cu₂O‐NP is more efficient in catalytic reactions in water for both aliphatic and aromatic azides and alkynes and less toxic than the commonly used CuSO₄/reductant catalyst systems.     

Click Chemistry合成1,2,3-三唑氨基酸衍生物

通过W ong叠氮转化和亲核取代反应,分别合成了叠氮苯丙氨酸、叠氮丙氨酸、苄基叠氮,采用上述叠氮化物与L-炔丙基甘氨酸进行C lick反应,合成了3个1,4-取代1,2,3-三唑氨基酸衍生物:2-氨基-3-[1-(1-羧基-2-苯乙基)-1H-1,2,3-三唑-4-基]丙酸、3,3-′(1H-1,2,3-三唑-1,4-基)双(2-氨基丙酸)和2-氨基-3-(1H-1,2,3-三唑-1-苄基-4-基)丙酸,收率分别是76%、62%和68%,产物结构经核磁共振波谱、质谱、红外光谱进行了表征。1,2,3-三唑氨基酸衍生物含双功能螯合基团,是很有潜力的fac-[188Re(CO)3(H2O)3]+放射性标记配体。     

Current Approaches for RNA Labeling in Vitro and in Cells Based on Click Reactions

Over recent years, click reactions have become recognized as valuable and flexible tools to label biomacromolecules such as proteins, nucleic acids, and glycans. Some of the developed strategies can be performed not only in aqueous solution but also in the presence of cellular components, as well as on (or even in) living cells. These labeling strategies require the initial, specific modification of the target molecule with a small, reactive moiety. In the second step, a click reaction is used to covalently couple a reporter molecule to the biomolecule. Depending on the type of reporter, labeling by the click reaction can be used in many different applications, ranging from isolation to functional studies of biomacromolecules. In this minireview, we focus on labeling strategies for RNA that rely on the click reaction. We first highlight click reactions that have been used successfully to label modified RNA, and then describe different strategies to introduce the required reactive groups into target RNA. The benefits and potential limitations of the strategies are critically discussed with regard to possible future developments.     

超分子材料研究进展

本文综述了超分子材料的发展概况,并介绍了超分子器件、超分子液晶、超分子生物材料和超分子纳米材料等超分子化技术的研究进展,展望了超分子材料的发展前景及其开发应用潜力。     

Protein Iodination by Click Chemistry

Two steps to click iodine : We have developed a two‐step reaction for protein iodination using click chemistry. With this method, which is summarized in the scheme, covalent attachment of a stable iodine‐containing aromatic azide moiety to an alkyne‐containing protein was achieved.

     

Dual Stimuli-Responsive Cross-Linked AIE Supramolecular Polymer Constructed through Hierarchical Self-Assembly

Herein, we report the successful construction of a new family of dual stimuli-responsive AIE cross-linked supramolecular polymer through the strategy of hierarchical self-assembly. A novel dipyridyl donor building block G1 containing tetraphenylethylene (TPE) moiety was designed and synthesized. Notably, two nitrile units were attached onto G1 , which were employed as the guest for the further host-guest interaction with pillar[n]arene derivatives. The rhomboidal metallacycle G2 with four nitrile units was firstly constructed through coordination-driven self-assembly. Subsequently, the cross-linked supramolecular polymers H₂⊃G2 were then generated through host-guest interactions. It should be noted that the obtained supramolecular polymer displayed interesting AIE properties due to the restriction of TPE intramolecular motions within the polymeric network. More importantly, by taking advantages of dynamic nature of both coordination bonds and host-guest interactions, the resultant supramolecular polymer displayed dual stimuli-responsive fluorescent transitions under different stimuli such as the competitive guest and halide anion.     

“链接”化学在高分子合成中的应用

简介了"链接"化学的基本特点,综述了近几年来叠氮-炔"链接"化学在合成不同结构聚合物中的应用。     

Synthesis of Ferrocene-containing Polyacetylenes by Click Chemistry

Ferrocene-containing polyacetylenes are synthesized in good yields by Cu-catalyzed click reactions of azido moieties of poly[(6-chloro-1-phenyl-1-hexyne)-co-(6-azido-1-phenyl-1-hexyne)] and poly{1-[(4-azidohexyloxy)phenyl]-2-phenylacetylene} with ethynylferrocene. All the organometallic polymers are completely soluble in common organic solvents such as chloroform, THF and toluene. Spectroscopic analyses reveal that all the azido functional groups have cyclized with ethynylferrocene. With the incorporation of ferrocene rings into the polyacetylene structure, the resulting polymers show enhanced thermal stability and redox activity. This communication is dedicated to Professor Ian Manners and his scientific accomplishments     

Modulation of Mitochondriotropic Properties of Cyanine Dyes by in Organello Copper‐Free Click Reaction

Cyanine (Cy) dyes show a general propensity to localize in polarized mitochondria. This mitochondriotropism was used to perform a copper‐free click reaction in the mitochondria of living cells. The in organello reaction of dyes Cy3 and Cy5 led to a product that was easily traceable by Förster resonance energy transfer (FRET). As determined by confocal laser scanning microscopy, the Cy3–Cy5 conjugate showed enhanced retention in mitochondria, relative to that of the starting compounds. This enhancement of a favorable property can be achieved by synthesis in organello, but not outside mitochondria.     

Phospha‐Michael Addition as a New Click Reaction for Protein Functionalization

A new type of click reaction between an alkyl phosphine and acrylamide was developed and applied for site‐specific protein labeling in vitro and in live cells. Acrylamide is a small electrophilic olefin that readily undergoes phospha‐Michael addition with an alkyl phosphine. Our kinetic study indicated a second‐order rate constant of 0.07 m ^?1 s^?1 for the reaction between tris(2‐carboxyethyl)phosphine and acrylamide at pH 7.4. To demonstrate its application in protein functionalization, we used a dansyl–phosphine conjugate to successfully label proteins that were site‐specifically installed with N^?‐acryloyl‐l ‐lysine and employed a biotin–phosphine conjugate to selectively probe human proteins that were metabolically labeled with N‐acryloyl‐galactosamine.     

Supramolecular Assemblies of Thioflavin T with Cucurbiturils: Prospects of Cooperative and Competitive Metal Ion Binding

Of late, molecular-recognition-guided supramolecular assembly and its relevance in the development of highly stable and active photofunctional materials have drawn much attention. In this review, the non-covalent interaction of a biologically important dye, thioflavin T (ThT), with cucurbituril macrocycles, especially, cucurbit[7]uril (CB7) and cucurbit[8]uril (CB8), and the response of the resulting molecular assemblies towards the metal ions have been discussed. The interaction of ThT with CB7 leads to significant enhancement in the fluorescence yield, lifetime and modifications in the spectral features of ThT. These changes are assigned to the formation of 1 : 1 and 2 : 1 (CB7⋅ThT) complexes. However, with CB8 a distinct evolution of a hitherto unexplored strong excimer emission band having maximum at 570 nm is observed. The strong ion–dipole interactions provided by the carbonyl portals of the CB8 adequately support the stabilization of two π-stacked ThTs, both in 1 : 2 (CB8⋅ThT) and 2 : 2 stoichiometric ratio. In case of the 1 : 1 (CB7⋅ThT) system, the metal ion addition leads to the usual competitive binding interaction and decreases the fluorescence intensity. However, the addition of the same metal ion to the 2 : 1 (CB7⋅ThT) complex results in a novel cooperative metal ion binding to the complex, leading to the formation of a highly fluorescent supramolecular capsule. Further addition of amantadine hydrochloride induces rupture of the capsular complex, projecting potential application in targeted drug delivery. The 2 : 2 (CB8⋅ThT) complex responds to the metal ion presence in a competitive way, which allows demonstration of a fluorescence on–off mechanism.     

Supracolloidal Assemblies as Sacrificial Templates for Porous Silk-Based Biomaterials

Tissues in the body are hierarchically structured composite materials with tissue-specific properties. Urea self-assembles via hydrogen bonding interactions into crystalline supracolloidal assemblies that can be used to impart macroscopic pores to polymer-based tissue scaffolds. In this communication, we explain the solvent interactions governing the solubility of urea and thereby the scope of compatible polymers. We also highlight the role of solvent interactions on the morphology of the resulting supracolloidal crystals. We elucidate the role of polymer-urea interactions on the morphology of the pores in the resulting biomaterials. Finally, we demonstrate that it is possible to use our urea templating methodology to prepare Bombyx mori silk protein-based biomaterials with pores that human dermal fibroblasts respond to by aligning with the long axis of the pores. This methodology has potential for application in a variety of different tissue engineering niches in which cell alignment is observed, including skin, bone, muscle and nerve.     

含1,2,3-三氮唑肉桂酸衍生物的合成

1,2,3-三氮唑环作为药效基团呈现出多种生物活性,以4-硝基苯甲醛为原料,合成了叠氮基肉桂酸,并以此为原料,CuI为催化剂,与端基炔烃进行1,3-偶极环加成反应,合成含1,2,3-三氮唑功能基的肉桂酸衍生物。