An Artificial Single Molecular Channel Showing High Chloride Transport Selectivity and pH-Responsive Conductance

Inspired by the unique structure and function of the natural chloride channel (ClC) selectivity filter, we present herein the design of a ClC-type single channel molecule. This channel displays high ion transport activity with half-maximal effective concentration, EC₅₀, of 0.10 μM, or 0.075 mol % (channel molecule to lipid ratio), as determined by fluorescent analysis using lucigenin-encapsulated vesicles. Planar bilayer lipid membrane conductance measurements indicated an excellent Cl⁻/K⁺ selectivity with a permeability ratio P /P up to 12.31, which is comparable with the chloride selectivity of natural ClC proteins. Moreover, high anion/anion selectivity (P /P =66.21) and pH-dependent conductance and ion selectivity of the channel molecule were revealed. The ClC-like transport behavior is contributed by the cooperation of hydrogen bonding and anion–π interactions in the central macrocyclic skeleton, and by the existence of pH-responsive terminal phenylalanine residues.     

Synthetic K+ Channels Constructed by Rebuilding the Core Modules of Natural K+ Channels in an Artificial System

Different types of natural K⁺ channels share similar core modules and cation permeability characteristics. In this study, we have developed novel artificial K⁺ channels by rebuilding the core modules of natural K⁺ channels in artificial systems. All the channels displayed high selectivity for K⁺ over Na⁺ and exhibited a selectivity sequence of K⁺≈Rb⁺ during the transport process, which is highly consistent with the cation permeability characteristics of natural K⁺ channels. More importantly, these artificial channels could be efficiently inserted into cell membranes and mediate the transmembrane transport of K⁺, disrupting the cellular K⁺ homeostasis and eventually triggering the apoptosis of cells. These findings demonstrate that, by rebuilding the core modules of natural K⁺ channels in artificial systems, the structures, transport behaviors, and physiological functions of natural K⁺ channels can be mimicked in synthetic channels.     

Self-assembly of nitroxide radicals via halogen bonding—directional NO?I interactions

Novel supramolecular self-assemblies of nitroxide free radicals via noncovalent halogen bonding are synthesised. A directional NO?I interaction is observed in a one-dimensional coordination polymer consisting of alternating electron donor and acceptor molecules.     

Perfluorocarbon-hydrocarbons self-assembly: halogen bonding mediated intermolecular recognition

Halogen bonding is discussed as an interaction that is capable of overcoming the reluctance shown by fluorinated compounds towards interactions with hydrocarbons. This non-covalent interaction is sufficiently strong to enact formation of supramolecular architectures where perfluorocarbons, hydrocarbons, and inorganic salts are self-assembled. Examples are discussed which exemplify the consistency and versatility of this interaction in affording numerous and structurally different hybrid materials. The importance of fluorine in determining the overall packing of the formed architectures is also highlighted.     

Pentaerythritol tetrakis(4-iodo-2,3,5,6-tetrafluorophenyl) ether: a tecton for the self-assembly of double strand 1D infinite chains

The p-iodotetrafluorophenyl motif has been appended to the four alcoholic groups of pentaerythritol to give the corresponding tetraether 1, which works as an effective tecton in halogen bonding based crystal engineering. In fact, in the solution and the solid phases, the halogen bonding drives the self-assembly of this ether with primary, secondary, and tertiary amines as well as with pyridine derivatives. Co-crystals are isolated where 1 invariably works as a tetradentate halogen bonding donor. Double strand, 1D, infinite chains are formed where the nitrogen substituted motifs are pinned in positions that fulfil Schmidt's requirements for solid phase photocycloaddition reactions. Quantitative yields and complete stereoselectivity have been obtained in the cycloaddition reaction.     

Halogen-bonded and interpenetrated networks through the self-assembly of diiodoperfluoroarene and tetrapyridyl tectons

The formation of two organic interpenetrated networks on halogen bonding driven self-assembly of diiodoperfluorarenes with tetrapyridyl tectons is described. Both architectures exhibit two-dimensional square 4⁴ networks; with either a 2-fold interpenetration of class IIa or a 3-fold interpenetration of class Ia. Diiodoperfluoroarenes are proven robust tectons in the design of interpenetrated networks based on the expansion strategy.     

A Dual‐Ion Organic Symmetric Battery Constructed from Phenazine‐Based Artificial Bipolar Molecules

Symmetric batteries received an increasing research interest in the past few years because of their simplified fabrication process and reduced manufacturing cost. In this study, we propose the first dual‐ion organic symmetric cell based on a molecular anion of 4,4′‐(phenazine‐5,10‐diyl)dibenzoate. The alkali salt of 4,4′‐(phenazine‐5,10‐diyl)dibenzoate allows a facile transport of cations and large anions, and remains stable in both oxidized and reduced states. The large potential difference between phenazine and benzoate results in a high cell voltage of 2.5 V and an energy density of 127 Wh kg^?1 at a current rate of 1 C. The introduction of bipolar organic materials may further consolidate the development of symmetric batteries that are fabricated from abundant elements and environmentally friendly materials.     

Covalently Linked Hexakis(m-Phenylene Ethynylene) Macrocycles as Molecular Nanotubes

The construction of nanotubular structures with non-deformable inner pores is of both fundamental and practical significance. Herein we report a strategy for creating molecular nanotubes with defined lengths. Macrocyclic (MC) units based on shape-persistent hexakis(m-phenylene ethynylene) (m-PE) macrocycle MC-1 , which are known to stack into hydrogen-bonded tubular assemblies, are tethered by oligo(β-alanine) linkers to give tubular stacks MC-2 and MC-4 that have two and four MC units, respectively. The covalently linked MC units in MC-2 and MC-4 undergo face-to-face stacking through intramolecular non-covalent interactions that further results in the helical stacks of these compounds. Oligomer MC-4 can form potassium and proton channels across lipid bilayers, with the channels being open continuously for over 60 seconds, which is among the longest open durations for synthetic ion channels and indicates that the thermodynamic stability of the self-assembling channels can be drastically enhanced by reducing the number of molecular components involved. This study demonstrates that covalently tethering shape-persistent macrocyclic units is a feasible and reliable approach for building molecular nanotubes that otherwise are difficult to create de novo. The extraordinarily long lifetimes of the ion channels formed by MC-2 and MC-4 suggest the likelihood of constructing the next-generation synthetic ion channels with unprecedented stability.     

One‐Dimensional Channels Encapsulated in Supramolecular Networks Constructed of Zinc(II), Manganese(II), or ­Nickel(II) Atoms with 3‐(Carboxymethyl)‐2, 7‐dimethyl‐3H‐benzo[d]imidazole‐5‐carboxylic Acid

Four complexes with supramolecular architectures, namely, MZCA · 3H₂O ( 1 ), [Zn(H₂O)₆]²⁺ · [MZCA]₂ · [H₂O]₆ ( 2 ), [Mn(MZCA)₂(H₂O)₄] · 2H₂O ( 3 ), and [Ni(MZCA)₂(H₂O)₄] · 2H₂O ( 4 ) [MZCA = 3‐(carboxymethyl)‐2, 7‐dimethyl‐3H‐benzo[d]imidazole‐5‐carboxylic acid], were synthesized and characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. Complexes 1 and 2 display a remarkable 3D network with 1D hydrophilic channels. Complexes 3 and 4 are isostructural and exhibit a 3D structure encapsulating 1D 24‐membered ring microporous channels. The UV/Vis and fluorescent spectra were measured to characterize complexes 1 – 4 . The thermal stability of complexes 2 – 4 were also examined.     

基于5-氯烟酸的锌(Ⅱ)和镉(Ⅱ)配合物的合成、晶体结构及荧光性质(英文)

通过水热方法,以5-氯烟酸(5-ClnicH)和2,2′-联咪唑(2,2′-biimidazole)分别与Zn(NO3)2·6H2O和Cd(NO3)2·4H2O反应,合成了2个配合物[Zn(5-Clnic)2]n(1)和[Cd(5-Clnic)2(H2biim)2](2),并对其结构和荧光性质进行了研究。结构分析结果表明配合物1和2分别属于单斜晶系,C2c空间群和三斜晶系,P1空间群。配合物1具有二维层状结构,而且这些层通过Cl…Cl卤键作用进一步形成了三维超分子框架。2为单核镉配合物,通过分子间N-H…O、C-H…N和C-H…Cl氢键作用,单核的分子被进一步连接成了三维超分子结构。配合物1和2在室温下能分别发出很强的紫色和绿色荧光。     

细胞膜离子通道的一个非线性动力学模型

提出一个关于细胞膜离子通道的非线性动力学模型，此模型克服了Liebovitch模型的一些严重缺陷，也更符合通道中离子运动实际．模型导出的Ⅰ-Ⅴ曲线与实验结果符合得很好．     

Self-assembly of vesicles from the stacking of a dipodal F?H-N hydrogen bonded arylamide foldamer

In this paper, we report the synthesis and self-assembling behavior of an F?H-N hydrogen bonding-induced arylamide-based dipodal foldamer. SEM, AFM, TEM, and XRD studies reveal that this preorganized oligomer stacks to form vesicles in methanol-chloroform (10-70%) binary solvents due to the strong stacking interaction of the folded segments and the supramolecular polymeric feature of the dipodal molecule in the stacked state. In contrast, a simple folded molecule can give rise to vesicles only when the chloroform content is 45-55%.     

A trinuclear Cu(II) precursor for solvatochromically distinguishing CH3OH from C2H5OH

Abstract

In order to develop an easy and rapid identification method for distinguishing CH₃OH from C₂H₅OH, a new carbonate-based trinuclear Cu(II) precursor, [Cu₃(bpy)₆(μ₃-CO₃)(CH₃OH)](BF₄)₄·(CH₃OH)₂·(H₂O)₂ (1), has been isolated. We report here the synthesis, crystal structure, and characterizations by various spectroscopic (IR, UV–Vis, powder XRD) techniques, as well as the solvatochromic behavior of this coordination compound. Its X-ray crystal structure reveals that the main structure of 1 consists of three [(bpy)₂Cu]²⁺ centers, which are bridged by carbonate via a μ₃-η¹,η¹,η¹ fashion. Strong O–H?O hydrogen bonding between the carbonate and solvent molecules has been observed for the first time in similar structures. Its ground powder exhibits solvatochromic behavior that selectively distinguishes CH₃OH from C₂H₅OH.     

A New Lattice Inclusion Host Involving Double-stranded Columns of Diol Molecules [1]

Abstract

Crystallization of dialcohol 4 from benzene yields an inclusion compound whose crystal structure [(C₁₃H₂₄O₂)₂·(C₆H₆), P2₁/c, a 7.918(2), b 13.505(2), c 14.924(5) Å, β 109.30(1)°, Z 2, R 0.069] shows that the host molecules are present as parallel doubly-stranded columns. Each column is constructed from one strand of (+)-, and a second of (-)-, enantiomers of 4. These two chirally pure strands are linked through a continuous chain of hydrogen bonding …O—H…O—H…O—H… to complete the column, and the benzene guests occupy interstitial sites between the parallel columns.     

Self-assembly and proton conductance of organic nanotubes from pillar[5]arenes

Organic nanotubes have been assembled from pillar[5]arenes 1 and 2. Compound 1 gelates organic solvents through the formation of tubular fibers which are evidenced by TEM and XRD experiments, while 2 assembles into two different channels under the template effect of water wires. In addition, the water wires in the nanotubes of 2 can be under selective proton conductance. The results described herein represent a new strategy for building tubular structures.     

Ion Selectivity of Water Molecules in Subnanoporous Liquid-Crystalline Water-Treatment Membranes: A Structural Study of Hydrogen Bonding

We demonstrate hydrogen-bonded structures of water in self-organized subnanoporous water treatment membranes obtained using synchrotron-based high-resolution soft X-ray emission spectroscopy. The ion selectivity of these water treatment membranes is usually understood by the size compatibility of nanochannels in the membrane with the Stokes radius of hydrated ions, or by electrostatic interaction between charges inside the nanochannels and such ions. However, based on a comparison between the hydrogen-bonded structures of water molecules in the nanochannels of the water treatment membrane and those surrounding the ions, we propose a definite contribution of structural consistency among the associated hydrogen-bonded water molecules to the ion selectivity. Our observation delivers a novel concept to the design of water treatment membranes where water molecules in the nanochannel can be regarded as a part of the material that controls the ion selectivity.     

The Nature of Halogen⋅⋅⋅Halogen Interactions: A Model Derived from Experimental Charge‐Density Analysis

Slightly attractive : The attractive and anisotropic nature of the Cl???Cl interaction in C₆Cl₆ is experimentally demonstrated from an expansion of the electron density ρ( r ) around the chlorine nuclei. The interaction is explained in a model in which there is a bonding attraction involving electron‐deficient (see picture, blue) and electron‐rich (red) regions of adjacent Cl atoms.

     

两个包含联苯三羧酸配体的铜(II)和锰(II)配合物的合成、晶体结构及磁性质

采用水热方法,用联苯三羧酸配体(H3dppa)和4,4′-联吡啶(4,4′-bipy)分别与CuCl_2·2H_2O和MnCl_2·4H_2O反应,合成了一个具有零维双核铜结构的配合物[Cu_2(Hdppa)_2(4,4′-bipy)(H_2O)_4]·4,4′-bipy·6H_2O(1)和一个基于双螺旋链单元的三维配位聚合物{[Mn_3(μ_5-dppa)_2(4,4′-bipy)(H_2O)_2]·4H_2O}_n(2),并对其结构和磁性质进行了研究。结构分析结果表明2个配合物分别属于三斜和单斜晶系,P1和C2/c空间群。配合物1具有零维双核铜结构,而且这些双核铜单元通过O-H…O/N氢键作用进一步形成了三维超分子框架。而配合物2中存在一个双螺旋锰链单元,这些锰链单元又通过配体进一步连接成了三维结构。研究表明,配合物2中相邻锰离子间存在反铁磁相互作用。     

Synthesis of trisubstituted furans from 2-bromo-5-methylfuranvia halogen migrations and their selective preventions

Summary New trisubstituted furans exhibiting two different substitution patterns were synthesizedvia lithiation of 2-bromo-5-methylfuran. Choice of appropriate reaction parameters enabled selective halogen dance reactions, affording 2-substituted 3-bromo-5-methylfurans upon quenching with various electrophiles. Moreover, from the same starting material also complete prevention of halogen migration could be achieved, thus providing selective access to 3-substituted 2-bromo-5-methylfurans.

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Synthese dreifachsubstituierter Furane aus 2-Brom-5-methylfuranvia Halogenwanderung und deren selektiver Verhinderung

Zusammenfassung Durch Lithiierung von 2-Brom-5-methylfuran konnten Furane mit zwei verschiedenen Substitutionsmustern synthetisiert werden. Es wurden Reaktionsbedingungen für eine kontrollierte Halogenwanderungsreaktion entwickelt, durch die nach Quenchen mit verschiedenen Elektrophilen 2-substituierte 3-Brom-5-methylfurane erhalten wurden. An demselben Edukt konnte auch vollständige Hintanhaltung der Umlagerung erzielt werden, wodurch Zugang zu 3-substituierten 2-Brom-5-methylfuranen geschaffen wurde.