Synthesis and crystal structure of tetranuclear zinc benzoate

A tetranuclear zinc benzoate Zr4O(C6H5CO2)6 was synthesized and characterized by X-ray single crystal determination. It crystallizes in cubic, space group Ia-3d. Its crystal cell is very large, α=4.10063(18)nm, V=68.953(5)nm^3 and Z=48. The structure is composed of discrete Zr4O(C6H5CO2)6 molecules. In each molecule, four zinc atoms are held together by a central oxygen atom, which results in the formation of a regular tetrahedron. All benzoate ligands coordinate to zinc atoms in a bidentate bridging mode. Each zinc atom is in a slightly distorted tetrahedral geometry, coordinated by three benzoate oxygen atoms and the central oxygen atom. The intermolecular interactions result in the formation of a three-dimensional supramolecular framework, with non-intersecting parallel channels.     

High pressure supramolecular chemistry

High pressure supramolecular chemistry is a developing interdisciplinary field. The use of high pressure for the study and fabrication of supramolecular systems has been explored only in the past few years. Such studies would shed light on the nature of the structures and functions of the complex supramolecular architectures. In this review, systematic progress made in this field is introduced based on the recent achievements. Special attention is paid to pressure-driven novel properties and functions of supramolecular assemblies resulting from the changes of molecular conformations, intermolecular interactions and supramolecular arrangements under high pressure.     

Crystal structure, magnetic and photoelectric properties of coordination polymer[ Co2（C3H4N2）4（ C10H2O8） ]n

The coordination polymer is designed and synthe-sized through the choice of organic ligand and coordina-tion geometry of metal ion as well as the control over theinfinite network topology structure, which usually con-tains both the characteristic of the organic molecules andmetal ions. So, it exhibits more singular function and haspotential application in optics, electrics, information, ca-talysis, medicament, metallurgy, novel material and lifesciences fields. And it has been the confluence m…     

IR study on hydrogen bonding in epoxy resin–silica nanocomposites

The chemical and physical interactions between ingredients in composites play an important role in the improvement of service properties. The nucleophilic addition between polymer and isophoron diisocyanate molecules was monitored by FT-IR technique. The intensity loss of isocyanate absorption band in conjunction with the intensity growth of carboxyl absorption band indicates the progress of reaction. FT-IR spectroscopy was also adopted to examine the intermolecular hydrogen bonding of epoxy resin with silica as well as intramolecular one within polymer matrix. The vibration frequency of carboxyl group （-C=O） and hydroxyl group （-OH） shifts from 1736 to 1728 cm^-1and 3420 to 3414 cm^-1, respectively, indicating the occurrence of hydrogen bonding between -C=O and -OH. The vibration frequency of Si-OH moves from 3435 to 3414 cm^-1, suggesting the involvement of silica. Whereas the vibration frequency of pending -OH in polymer chain moves from 3435 to 3420 cm^-1 or 3414 cm^-1, proposing that this kind of interaction can also happen within polymer matrix.     

Structural diversity and reactivity of d^10 metal- （4-pyridylthio）acetate system

The hydrothermal synthesis and crystal structures of four coordination polymers, namely, 2D [Zn（μ3-ta）（pytaH）]n （1）, 2D [Zn（μ3-pyta）Cl]n （2）, 1D [Cd（μ-pyta）2（H2O）]n （3）, and 3D [Cd（μ3-pyta）（μ-Cl）]n （4） （pyta = （4-pyridylthio）acetate, ta = thioglycolate）, are reported. They are based on （4-pyridylthio）acetate and its derived ligand. The ta^2- ligand present in 1 was generated from an in situ C（sp^2）-S bond cleavage of the pyta ligand. In these compounds, versatile intermolecular interactions, such as close S…S interactions and strong （O-H…O/N/S） or weak （C-H…O/S, C-H…Cl） hydrogen bonding interactions, play an important role in the formation of three-dimensional supramolecular networks in the solid state.     

IR study on hydrogen bonding in epoxy resin-silica nanocomposites

The chemical and physical interactions between ingredients in composites play an important role in the improvement of service properties. The nucleophilic addition between polymer and isophoron diisocyanate molecules was monitored by FT-IR technique. The intensity loss of isocyanate absorption band in conjunction with the intensity growth of carboxyl absorption band indicates the progress of reaction. FT-IR spectroscopy was also adopted to examine the intermolecular hydrogen bonding of epoxy resin with silica as well as intramolecular one within polymer matrix. The vibration frequency of carboxyl group (-C=O) and hydroxyl group (-OH) shift from 1736cm^-1to 1728 cm^-1and 3420 cm^-1to 3414 cm^-1 respectively, indicating the occurrence of hydrogen bonding between -C=O and -OH. The vibration frequency of Si-OH moves from 3435 cm^-1 to 3414 cm-1, suggesting the involvement of silica. Whereas the vibration frequency of pending –OH in polymer chain moves from 3435 cm^-1to 3420 cm^-1or 3414cm^-1, proposing this kind of interaction can also happen within polymer matrix.     

Effects of Polyethylene Oxide Concentration on the Size of Beads in Electrospun Beaded Nanofibers

Embedding particle drugs in beaded nanofibers by electrospinning has been shown a potential approach to control drug release in tissue engineering. The bead size is one of the critical parameters in controlling the drug release rate. In this study,the relationship between polymer concentration and beads size was investigated. Aqueous polyethylene oxide（ PEO） solutions with different concentrations were prepared to obtain various beaded nanofibers by electrospnning. Optical microscope and scanning electron microscope（ SEM） were used to observe the variation tendency of bead size. With an increase in the polymer concentration,the diameter of fibers between beads became bigger,while the fiber uniformity improved. In addition, the polymer concentration influenced the distribution of bead diameter. Higher polymer concentration would reduce the possibility of small-sized beads formation and improve the uniformity of bead diameter. The study provides a possible way to control the size of beads,which is helpful for further research on the control of particle drug release.     

New concept on coal structure and new consideration for the generation mechanism of oil from coal

The traditional two_phase structural model of coal based on the chemical covalence bonding has to be revised since recent discoveries of powerful mixed solvent such as CS-2/C-5H-9N, giving extra high yields in coal extraction at room temperature. It is believed that the physically associated interactions play important roles in the structure of coal. A composite model of coal is suggested. The organic matter of coal is mainly composed of some parts: the rigid 3_D macromolecules linked with chemical bonds; the polar molecules of high and moderate molecular weights, corresponding to asphaltenes and resins; the hydrocarbons with lower molecular weights. The polar molecules are associated by physical interactions (such as hydrogen bonding, charge transfer interactions, π_π interactions of aromatic sheets, etc.) each other and with macromolecules to form the network structure, in which some smaller nonpolar molecules are trapped. Based on the new concept of the composite coal model, some considerations for the generation mechanism of oil from coal have approached. Since the energy level of physical association is much lower than the chemical covalent bonding, the upper threshold of oil window for the generation of oil from coal seems not to be limited strictly after the theory of oil generation at the latter stage of the kerogen maturation. It looks reasonable to pay more attention to the geological conditions including the salt, water, minerals and environments of the sedimentation. The evolution process of physically associated interactions in the composite structure of coal and the generation of oil is thought to be intimately influenced by these factors.     

Fluorescent detection of coenzyme A by analyte-induced aggregation of a cationic conjugated polymer

A new cationic conjugated polymer was designed and synthesized to optically discriminate coenzyme A(CoA) among structurally similar biomolecules, ATP, ADP and AMP. The analyte-induced aggregation of the conjugated polymer by π-stacking between their main chains leads to the fluorescence quenching. Except for the similar adenosine and phosphate moieties as those in ATP, ADP and AMP, the CoA molecule also includes a long side chain that is favorable for hydrophobic interactions. Thus, CoA can form a complex with oppositely charged conjugated polymer by cooperative electrostatic and hydrophobic interactions, whereas ATP, ADP and AMP form the complexes with oppositely charged conjugated polymer mainly by electrostatic interactions. The increase of the ion strength of the assay solution screens the electrostatic attractions, and the remaining hydrophobic interactions dominate the formation of PFP-PTF/CoA complex. At this case, the quenching efficiency of PFP-PTF by CoA is much higher than that by ATP, ADP and AMP, which impart the PFP-PTF to sense CoA from these interferencing species.     

Supramolecular Organization of Porphyrin and Phthalocyanine by Complementary Coordination

1 Results We have already established a methodology of supramolecular organization of porphyrin and phthalocyanine by complementary coordination of the imidazolyl substituent to their metal centers.Since the stability constants reached a range of 1011 to 1012 M-1 in nonpolar solvents,it allowed construction of stable structures such as special pair of photosynthetic reaction center and light-harvesting antenna complex of photosynthetic bacteria.Here,we report one-dimensional array of porphyrin for the development of molecular wire and porphyrin-phthalocyanine conjugate as a molecular memory.     

2-（间甲氧基）苯基咪唑二羧酸构筑的锌配位聚合物的制备及晶体结构

采用有机配体2-（3-甲氧基）苯基-4,5-咪唑二羧酸（H,MOPhIDC）和辅助配体邻菲啰啉（Phen）与Zn（Ⅱ）在水热条件下自组装,制得一维配位聚合物[Zn（HMOPhIDC）（Phen）]n．通过元素分析、红外光谱以及X射线单晶衍射对它的分子结构进行表征．结果表明：通过分子间氢键以及π-π堆积力的作用,形成了三维固态超分子结构．该配合物在362℃以下稳定．     

[Cd(phen)(NO3)2(H2O)]n:从一维多核配位链通过氢键和芳环堆积相互作用构筑三维超分子网络

通过Cd(NO3)2与邻二氮杂菲(phen)和丁二酸在水-甲醇溶剂中反应制备了一个新型硝酸根桥联配位聚合物[Cd(phen)(NO3)2(H2O)]n(1).用X-射线衍射技术在室温下测定了标题化合物的晶体结构单斜晶系,P21空间群(No.4),晶胞参数a=1.029 79(10)nm,b=0.725 41(7)nm,c=1.030 16(10)nm,β=110.486 0(10)°,V=0.720 88(12)nm3,Z=2.CdⅡ中心离子为六配位,处于由螯合phen配体、硝酸根离子和水所构成的CdN2O4扭曲多面体中.CdⅡ离子之间通过硝酸根离子连接形成一维无限锯齿形配位链,这些一维链通过phen和硝酸根离子间的C H…O相互作用进一步连接成二维结构.此外,这些二维结构之间存在芳环堆积相互作用,且通过层间水-硝酸根离子所组成的O-H…O氢键连接而形成三维超分子结构.     

苯五酸原位脱羧形成锌配合物的水热合成和结构研究

水热反应条件下,Zn( NO3)2·4H2O、苯五酸和2,2’-联吡啶反应生成一个新颖的配位聚合物[Zn2(1,2,3,5 -btc)(2,2'-bpy)2 (H2O)]n.0.5nH2O(1,2,3,5-btc=1,2,3,5-苯四酸),通过X射线单晶衍射分析、元素分析和红外光谱对它进行了表征,配合物的结构是由二维配...     

新型银配位聚合物的合成、结构及其光学性质(英文)

报道合成一种新型的带有正电荷的一维链状聚合物并对其结构进行表征.结果显示,分子间的π-π堆积作用增强了体系的稳定性,同时吡啶氮原子与NO3-中的氧形成了经典氢键.文中还通过红外以及单光子荧光对其结构和性质进行了讨论,并对配位后聚合物的荧光猝灭进行了合理解释.     

铜的一维配聚物和双(μ-硫)桥联二聚物的磁性研究

制备了铜的氯桥联的一维聚合物{[(CuClL'][Cl]}n和二聚体[CuLCl2]2, 测试了这两种化合物在1.8 ～ 300 K 范围内的变温磁化率. 理论拟合表明:通过氯原子或硫原子的传递作用,在铜离子之间存在弱的反铁磁偶合.     

配位聚合物[Ni(4,4''''-bpy)(H2O)4]·(SO42-)·(CH3OH)·(H2O)的合成与晶体结构

通过NiSO4·6H2O与4,4'-联吡啶在H2O-CH3OH混合溶液中反应,制备了配位聚合物[Ni(4,4′-bpy)(H2O)4]·(SO42-)·(CH3OH)·(H2O),并使用X射线单晶衍射技术对其结构进行了表征.此配合物含有三种分别沿[100]、[010]、[110]方向排列的无限长链,并通过其配位水分子与位于层间位置的SO42-形成氢键而连接成为超分子结构.     

基于含氮羧酸配体碱土金属配合物的研究进展

基于配位作用以及配体之间的多种弱相互作用(如氢键、π-π堆垛作用等),金属离子与有机配体之间经自组装形成结构新颖、性能独特的金属—有机超分子配合物,本文主要介绍了配位化学和金属—有机超分子框架结构的基本原理及其研究方法。     

[Cu2(bpa)2(phen)2(H2O)]2·H2O的合成和晶体结构

利用线形的芳香二羧酸与邻菲啉铜盐在水热的条件下合成一种新型的分子块化合物,这种分子块通过位于钝角位置的邻菲啉配体的芳香pp-识别作用自组装成第一例由菱形分子块的自组装形成二维多聚轮烷, 这种二维的层状结构通过邻菲啉配体的芳香pp-堆积作用形成具有独特拓扑结构的三维网络结构。     

配合物［Cu(NPG)2(H2O)2］·CH3CH2OH的合成、晶体结构与磁性研究

用溶液法合成了配合物［Cu(NPG)₂(H₂O)₂］·CH₃CH₂OH (HNPG=邻苯二甲酰甘氨酸),对其进行了元素分析,红外光谱,热重分析,磁性和X射线单晶衍射实验.单晶结构分析表明该晶体属于三斜晶系,P-1空间群,晶胞系数a=0.476 74(12) nm,b=0.113 19(3)nm,c=0.11 614(3)nm,α=106.468(4)°,β =100.114(5)°,γ=94.358(5)°,V=0.586 4(3) nm³,Z=1.Cu(II)通过O-C-O构成一维链状结构,分子间氢键将一维链连接为平面结构,氢键对分子结构稳定起到重要作用;配合物存在弱的反铁磁性.