Supramolecular Aggregates of Dendritic Cyclophanes (Dendrophanes) Threaded on Molecular Rods with Steroid Termini

Multinanometer-sized assemblies with molecular weights exceeding 14 000 are obtained by the threading of two dendritic cyclophanes (dendrophanes) onto molecular rods in which two testosterone termini are attached by rigid spacers to a central phenyl ring bearing two quaternary ammonium side chains. The formation of these structurally defined aggregates, in which the dendrophanes preferentially encapsulate the steroid termini (see picture), is driven by a combination of apolar interactions, hydrophobic desolvation, and ion pairing, and depends strongly on the length of the spacer.     

An electrochemically tuneable cyclodextrin-based molecular adapter

We report the synthesis of a cyclodextrin-based molecular adapter which has the propensity to form an electrochemically tuneable ternary complex with cyclophanes 2 or 3 and ferrocene 4 in non-aqueous and aqueous environments, respectively.     

An investigation of the complexation properties of cyclobis(paraquat-p-phenylene) in water

This article reports the characterization of pseudorotaxanes fabricated from cyclobis(paraquat-p-phenylene) 1, and 1,4-dialkyloxyphenyl derivative 2 or 1,5-dialkyloxynaphthalene derivative 3 in water. Addition of competing guest 3 to 1.2 or the electrochemical reduction of the cyclophane of 1.3 results in a dethreading of the original pseudorotaxane architecture.     

An investigation of the complexation of a TTF derivative with α-, β- and γ-cyclodextrins in aqueous media

This Letter, describes the complexation of α-, β- and γ-cyclodextrins (1-3) with TTF derivative 4 in water. In particular, we show using ¹H, ¹³C NMR, UV-vis spectroscopy and isothermal titration calorimetry that β-cyclodextrin 2 forms an effective complex with 4. Complex 2·4 can be conveniently disassembled upon the addition of 1-adamantanol.     

中国超分子聚合物的研究与动态

超分子聚合物是高分子科学与超分子科学交叉的研究方向.超分子聚合物的研究在中国引起了学术界的广泛兴趣,中国的学者们对推动此研究领域的发展做出了贡献,并在新的超分子聚合方法、可控超分子聚合以及功能超分子聚合物等方面取得了一系列重要的创新成果.本文总结和评述了中国超分子聚合物的研究与动态,并展望了超分子聚合物化学、超分子聚合物物理、超分子聚合物表征及功能超分子聚合物的未来发展.     

Dendrimers: From Design to Application—A Progress Report

A unique combination of a clearly defined particle structure and a very highly functionalized surface is offered by the topical dendrimers. Many groups work on this unusual molecular architecture to develop new applications. The most advanced progress in this respect is an MRI contrast agent based on dendrimers (see schematic representation) that facilitate the visualization of bloodstreams.     

Noncovalent Assembly of a Fifteen-Component Hydrogen-Bonded Nanostructure

A total of 72 hydrogen bonds are formed in the spontaneous association of calix[4]arene tetramelamine and barbituric acid derivatives to give nanosized assemblies of the type represented in the picture. These consist of 15 components that assemble in a completely diastereoselective sense: of the eight possible diastereomers only the all-staggered diastereoisomer is obtained.     

插销式分子器件——可利用酸碱调控的超分子准轮烷

含有吗啉的富π电子苯醚链化合物与缺π电子联吡啶环玢CPQT通过分子间的π-π堆积作用形成超分子准轮烷结构。研究发现,随着温度的变化,该准轮烷结构的相对运动速度加快,弱相互作用减弱;并进一步发现,随着酸和碱的依次加入,该准轮烷结构呈现"开"与"关"的"插销式"器件性能。     

Self-Assembly of Quinodimethanes through Covalent Bonds: A Novel Principle for the Synthesis of Functional Macrocycles

A multiplication of functional units was accomplished in a simple fashion by the tetramerization of a quinodimethane. This principle is demonstrated by the convergent construction of a macrocyclic molecule with 16 ferrocenes and a macrocyclic molecule with 16 dendritic units at the periphery of the molecule (see scheme). FG=functional group     

Searching for new host compounds: synthesis and characterization of novel crown ether-functionalized dendrimers

Novel lipophilic dendrimers as host compounds, that is, 7-15, containing crown ether moieties with different sizes as the core, surrounded by first, second or third generation poly(aromatic ether) wedges, were synthesized by the use of bis(bromomethyl)-substituted crown ethers and Fréchet-type poly(benzyl ether) dendrons as building blocks. The compounds were fully characterized.     

Characterization of Hydrogen-Bonded Supramolecular Assemblies by MALDI-TOF Mass Spectrometry after Ag+ Labeling

The high affinity of Ag ⁺ ions for aromatic π donors and cyano groups is exploited in a novel MALDI-TOF mass spectrometric method for the identification of hydrogen-bonded assemblies. The interaction with the Ag⁺ ions—which, for example, can be complexed by two phenyl groups in a sandwich-type manner (see drawing on the right)—provides positively charged assemblies in a nondestructive way.     

Self-Organization of a Heteroditopic Molecule to Linear Polymolecular Arrays in Solution

Like the proverbial monkey chain one heteroditopic self-complementary molecule, comprising a crown ether unit and a paraquat unit, catches a second such molecule in solution and thus by self-organization forms novel linear oligo- and polymolecular arrays (shown schematically; the crown ether unit is denoted by the ellipse, and the paraquat unit by the rectangle).     

Stilbenoid Dendrimers

A convergent synthesis in which all trans double bonds were constructed by Wittig–Horner reactions produces dendrimers of the general structure 1 . With long-chain alkoxy residues on the periphery of the benzene rings, the first two generations display liquid crystalline behavior.     

Resolution of Racemic 1,2-Dibromohexafluoropropane through Halogen-Bonded Supramolecular Helices

Halogen bonds , attractive intermolecular interactions between perfluoroalkyl bromides and bromide ions, are present in cocrystals of (−)-sparteinium hydrobromide ( 1 ) and (S)-1,2-dibromohexafluoropropane ( 2 ; shown schematically), and result in enantiopure and infinite supramolecular helices. The perfluorocarbon–hydrocarbon self-assembly allows the resolution of racemic 2 .     

Controlled Formation of Thiol‐Thiolate Hydrogen versus Disulfide Bonds between Two Iridium(III) Centers

Here, we report an iridium(III) coordination system with 2‐aminoethanethiolate (aet), which shows the formation of S?H???S hydrogen and S?S disulfide bonds in a controlled manner. Treatment of fac‐[Ir(aet)₃] with aqueous HBF₄ under aerobic conditions gave dinuclear [Ir₂(aet)₄(cysta)]²⁺ ([ 1 ]²⁺; cysta=cystamine) with a single S?S disulfide bond, while dimeric [Ir₂(aet)₃(Haet)₃](BF₄)₃ ([ 2 ](BF₄)₃) with a triple S?H???S hydrogen bond was formed by similar treatment under anaerobic conditions. Upon exposure to air, [ 2 ]³⁺ was converted to dinuclear [Ir₂(aet)₂(Haet)₂(cysta)]⁴⁺ ([ 3 ]⁴⁺), in which two Ir^III centers are spanned by a double S?H???S hydrogen bond and a single S?S disulfide bond. Complex [ 3 ]⁴⁺ was interconvertible with [ 1 ]²⁺ via the removal/addition of protons on S donors, accompanied by the intermolecular exchange of the fac‐[Ir(aet)₃] units. Complexes [ 1 ]²⁺, [ 2 ]³⁺, and [ 3 ]⁴⁺, isolated as BF₄^? salts, were fully characterized by single‐crystal X‐ray crystallography.     

A New Motif for the Self-Assembly of [2]Pseudorotaxanes; 1,2-Bis(pyridinium)ethane Axles and [24]Crown-8 Ether Wheels

Multiple intramolecular interactions help to stabilize the novel [2]pseudorotaxanes formed from 1,2-bis(pyridinium)ethane dications (which act as axles) and 24-membered crown ethers (which act as wheels; see structure). This is the first successful sythesis of [2]pseudorotaxanes with [24]crown-8 as the macrocycle.     

C-H?Br, C-Br?Br, and C-Br?π interactions in the crystal structures of mesitylene- and dimesitylmethane-derived compounds bearing bromomethyl units

X-ray structure determinations of mesitylene- and dimesitylmethane-derived compounds bearing bromomethyl units (compounds 1-3) show that the crystal packing of the molecules is characterized by the presence of C-H?Br interactions, such as BrCH₂?Br, CH₃?Br, and C_PhH?Br. In addition, C-Br?Br and C-Br?π interactions determine the crystal packing. The bromomethyl groups play a major role in the packing of 1-3.     

Supramolecular Daisy Chains

Our childhoods may be recalled when a self-complementary cation, endowed with both a dibenzo[24]crown-8 macroring and a secondary dialkylammonium sidearm, self-assembles to form a two-component supramolecular architecture that is reminiscent of a daisy chain (depicted schematically on the right). This daisy-chain-like superarchitecture is stabilized by a combination of [N⁺−H⋅⋅⋅O] hydrogen bonds and aryl–aryl stacking interactions.     

树枝状聚合物的应用研究进展

树枝状聚合物为纳米级单分散性大分子,其独特的分子结构和物理化学性质使之在众多领域有着广泛的用途。本文着重介绍了树枝状聚合物在超分子化学、生物医药、光化学、电化学和催化剂等领域中的应用研究进展。     

Synthesis of p-Phenylene Sulfide Molecular Asterisks

“Megastars” with aromatic central cores, some of which fluoresce, were synthesized by the efficient connection of the side arms to the core by using the MacNicol reaction. Depending on the length of the side arm precursor, second-, third- (depicted), or fourth-generation molecular asterisks were obtained; a twelve-armed molecular asterisk was prepared when the benzene core was replaced by a coronene one.