超分子化合物的合成与识别研究的新进展

简要介绍了超分子化学的产生发展及应用,重点综述了：①新型大环超分子化合物的合成及对阴离子的识别作用;②超分子受体的合成及对金属离子的识别作用;③新型二茂铁双内酯环蕃超分子受体的合成及选择性识别作用。并对超分子化学的发展进行了展望。     

Molecular and Supramolecular Structural Studies on Significant Repetitive Sequences of Resilin

Resilin is a member of the family of elastomeric proteins and is found in specialised regions of the cuticle of most insects, and provides low stiffness, high strain and efficient energy storage. It is best known for its role in insect flight and the remarkable jumping ability of fleas and spittle bugs. In common with other elastomeric proteins, the recently identified Drosophila melanogaster proresilin shows glycine‐rich repetitive sequences; in particular the N‐ and C‐terminal regions of the protein are dominated by 18 repeats of a 15‐residue sequence (SDTYGAPGGGNGGRP) and eleven repeats of a 13‐residue sequence (GYSGGRPGGQDLG), respectively. We synthesised and analysed the molecular and supramolecular structure of some polypeptides with sequences belonging to the glycine‐rich repeated domain of D. melanogaster resilin. The conformational studies performed by CD, FTIR and NMR spectroscopies pointed to the coexistence of two main conformational features, such as folded β‐turns and (quasi)extended structures (e.g., poly‐L ‐proline II conformation) in common with other elastomeric proteins; this suggests an elasticity mechanism for resilin common to other elastomeric proteins. Our data show that also in the case of resilin, repetitive sequences are characterised by autonomous structures almost independent of the remaining parts of the molecule as already extensively found for elastin. From a supramolecular point of view, a great tendency to aggregate in fibrous structures is observed, particularly for the resilin‐ inspired polypeptide (PGGGN)₁₀. This is encouraging for the development of resilin‐based biomaterials for the production of biocompatible medical devices, as well as high performing elastic materials.     

2-氨基嘧啶超分子配合物[Cu(2-AP)2(NO3)2]的合成与晶体结构

以2-氨皋嘧啶缩水杨醛席夫碱和硝酸铜为原料,在常温下,用甲醇和水为溶剂合成了配合物[Cu（2,Ap）2（NO3）2]（2-Ap=2,氨基嘧啶）。通过红外光潜、元素分析、X-射线单品衍射对它进行了结构解析和表征,并系统研究了配合物的结构特点。     

NMR Investigation of the Supramolecular Complex Formed by a Phenylboronic Acid-Ferrocene Electroactive Probe and Native or Derivatized β-Cyclodextrin

Specifically designed electrochemical sensors are standing out as alternatives to enzyme-based biosensors for the sensing of metabolites. In our previous works, we developed a new electrochemical assay based on cyclodextrin supramolecular complexes. A ferrocene moiety (Fc) was chemically modified by phenylboronic acid (4-Fc-PB) and combined with two different kinds of cyclodextrins (CDs): β-CD and β-CD modified by a dipicolylamine group (dpa-p-HB-β-CDs) for the sensing of fructose and adenosine-triphosphate (ATP), respectively. The aim of the present work is to better comprehend the features underlining the aforementioned complex formation. For the first time, a study about inclusion phenomena between the 4-Fc-PB electroactive probe with β-CD and with dpa-p-HB-β-CD was performed by using nuclear magnetic resonance (NMR) analysis. In particular, we focused on providing insights on the interaction involved and on the calculation of the binding constant of 4-Fc-PB/β-CD supramolecular complex, and elucidation about a drift in the time observed during the control experiments of the electrochemical measurements for the 4-Fc-PB/dpa-p-HB-β-CD supramolecular complex. In this sense, this paper represents a step further in the explanation of the electrochemical results obtained, pointing out the nature of the interactions present both in the formation of the inclusions and in the sensing with the analytes.     

阳离子聚电解质与阴离子表面活性剂大分子复合物的形成及其溶液流变性能

将不同阳离子电荷度的丙烯酰胺-丙烯酰氧乙基三甲基氯化铵共聚物与反电性阴离子十二烷基硫酸钠复合,由电导率测定发现两者依靠静电引力结合的大分子复合物存在着非电荷化学计量比关系。低于临界沉淀浓度时,大分子复合物能够保持分散溶解状态,溶液属于假塑性流体。并且分子复合作用使溶液的抗剪切稀释能力增强。     

Effects of the Molecular Design on the Supramolecular Organization of Luminescent Pt(II) Complexes

Self‐assembly is an extremely important processes that allows the constructions of large supramolecular architectures through encoded information present in the components. A subtle change in the chemical structure of the single unit can dramatically change the kinetics and thermodynamic pathway. We demonstrate that a minor change, introduced by designing the structure of a family of Pt(II) complexes can influence the color of the emission of the assemblies and their kinetic behaviour. The assembly processes, visualized by confocal microscopy, and detailed through photophysical measurements, reveal that the establishment of intermolecular interactions, as well as electronic factors lead to completely different assemblies in solution of the platinum compounds. A correlation between the observed behaviour and the chemical structure of the compounds is discussed and the results indicate a strong kinetic control of the supramolecular processes.     

Synthesis and Fluorescent Properties of Zn(II) Complex with Functionalized Polystyrene Containing Salicylaldehyde End Group

Summary Fuctionalized polystyrene ligand containing schiff base end group (N-Salicyliden-(4-methoxy-Anilin)) was obtained by condensation of p-methoxyanilin with polystyrene containing salicylaldehyde end group which was prepared through atom transfer radical polymerization (ATRP). The polystyrene ligand was applied to prepare Zn(II) complex. The polystyrene ligand and its complex were characterized through ¹H-NMR, IR, UV-Vis and fluorescent spectra. Compared with analogous Zn(II) complexs with small molecular schiff base, the complex was soluble in common solvents, easy to form film and showed intensive fluorescence. When excited at 330 nm, the complex emitted intense fluorescence at 500 nm. The effects of different molecular weights, amount of solvent in coordination reaction and reaction methods including conventional heating and microwave irradiation on Zn contents and fluorescent intensity were also discussed.     

New 2-pyridinealdehyde N 4-hydroxyethyl thiosemicarbazone and their Cd(II) and Cu(II) complexes: synthesis,spectral, in vitro antibacterial activity and molecular and supramolecular structure study

N ⁴-hydroxyethyl-pyridinealdehyde thiosemicarbazone (HL, 1) as a tridentate Schiff base has been synthesized by 1:1 reaction of S-methyl-3-((pyridyl)methyl) dithiocarbazate and 2-aminoethanol. Complexes [Cd(HL)₂](NO₃)₂ (2), [Cd(HL)I₂] (3), [Cd(HL)Cl₂] (4), [Cu(HL)₂](NO₃)₂ (5) and [Cu(HL)Cl₂] (6) have been obtained and characterized by elemental analyses, molar conductivities, and spectroscopic studies. The ligand molecule binds the metal ion using pyridyl nitrogen, azomethine nitrogen and the sulfur atoms. The crystal structure analysis of 3 has been determined and showed to be a distorted square pyramidal geometry complex. The inter- and intramolecular interactions give rise to a supramolecular network. Compounds 2, 3, 5 and 6 were assayed for their bioactivities against selected pathogens. Copper(II) complexes 5 and 6 showed antimicrobial activities against Gram-positive (Bacillus anthracis) and Gram-negative (Pseudomonas aeruginosa and Yersinia pseudotuberculosis) bacteria, complexes 2–4 showed antimicrobial activities against Bacillus atrophaeus, while the ligand itself showed antimicrobial activities against Escherichia coli and Y. pseudotuberculosis.     

Sulfobutylation of Beta-Cyclodextrin Enhances the Complex Formation with Mitragynine: An NMR and Chiroptical Study

Mitragynine (MTR), the main indole alkaloid of the well-known plant kratom (Mitragyna speciosa), is one of the most studied natural products nowadays, due to its remarkable biological effects. It is a partial agonist on the opioid receptors, and as such relieves pain without the well-known side-effects of the opioids applied in the clinical practice. MTR and its derivatives therefore became novel candidates for drug development. The poor aqueous solubility and low bioavailability of drugs are often improved by cyclodextrins (CyDs) as excipients through host-guest type complex formation. Among the wide variety of CyDs, sulfobutylether-beta-cyclodextrin (SBEβCyD) is frequently used and official in the European and U.S. Pharmacopoeia. Herein, the host-guest complexation of MTR with βCyD and SBEβCyD was studied using chiroptical and NMR spectroscopy. It was found by NMR measurements that MTR forms a rather weak (logβ₁₁ = 0.8) 1:1 host-guest complex with βCyD, while the co-existence of the 2MTR∙SBEβCyD and MTR∙SBEβCyD species was deducted from ¹H NMR titrations in the millimolar MTR concentration range. Sulfobutylation of βCyD significantly enhanced the affinity towards MTR. The structure of the formed inclusion complex was extensively studied by circular dichroism spectroscopy and 2D ROESY NMR. The insertion of the indole moiety was confirmed by both techniques.     

A Novel Aqua Ligand Assisted Water Octamer Confinement in the Hydrophilic Channels of a Zn(II) Supramolecular Architecture

A new two-dimensional polymeric [Zn₂(4-pzpt)(btc)(H₂O)₂·3H₂O] (1) (4-Hpzpt = 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole, H₃btc = 1,2,3-benzenetricarboxylate), has been synthesized and structurally characterized and features a 3D supramolecular framework with 1D hydrophilic channels formed by the interlayer hydrogen bonds. An unprecedented aqua ligand assisted octameric water cluster consisting of a quasiplanar cyclic hexameric core and two dangling water molecules is captured in 1. The thermal stability and solid state fluorescent property of 1 are discussed.     

一种不对称希夫碱配合物的合成及其对氯仿分子的选择性识别

利用邻苯二胺的分步缩合反应得到不对称希夫碱（HL）并合成了相应的金属配合物.采用自制空气舱进行氯仿清除率测量,配体HL和配合物MgL、CaL、TiL、Cr （Ⅲ）L、Co（Ⅱ）L、NiL、CuL、ZnL等对氯仿清除率的测量结果对比表明,铜配合物CuL对氯仿具有显著的清除效果.对铜配合物CuL和氯仿形成的单晶进行了晶体结构分析,发现氯仿分子已稳定地包合于配合物晶体骨絮中,并且氯仿分子上的氢和配体上的2个氧原子形成了氢键,其距离分别为2.176和2.637 A,这是由于氯仿分子中氢原子具有一定的酸性以及Cu（Ⅱ）的外围3d9电子构型中的单电子对该氢键的形成也起到一定的促进作用.     

Supramolecular Assembly between Polystyrene-block-Poly(4-vinylpyridine) and 4-Dodecylbenzenesulfonic Acid

In this study, the desired polymer was prepared by complexing the surf molecule, i.e., 4-dodecylbenzenesulfonic acid (DBSA), with polystyrene-block-poly(4-vinylpyridine) (PS-P4VP) and a comb-coil A-block-(B-graft-C) type of copolymer can be generated through a supramolecular assembly route. On the block copolymer scale, the PS blocks are phase-separated from the P4VP(DBSA) _x block (x denotes the molar ratio between DBSA and pyridine groups) according to the relatively constant low-temperature glass transition (T _g) corresponding to the PS phase. In contrast, the high-temperature T _g increased with the DBSA content; a fact associated with the chain packing situation in the P4VP(DBSA) _x block. Both low and high T _g's became more visible if samples were subjected to a two-stage annealing process. Corresponding X-ray diffraction study also indicates that annealing enhanced the layered structure in the P4VP(DBSA) _x phase. The corresponding one-dimension correlation function suggests that both polymer and surfactant layers increased with the increasing DBSA content. In addition, amounts of the associated DBSA related to the formation of macroscopic anisotropic domains, that is, birefrigency can only be detected for copolymers of high P4VP(DBSA) _x content (>70 wt%).     

Nanosecond T-Jump Experiment in Poly(glutamic acid): A Circular Dichroism Study

Poly(glutamic acid) has been studied with a nanosecond T-jump experiment. A new experimental set-up based on the frequency-quadrupling of an 82 MHz Titanium-Sapphire laser allows rapid CD measurements to be performed. Combining time-resolved absorption and circular dichroism at 204 and 220 nm, we are able to measure precisely the unfolding relaxation time as well as the helical fraction evolution. We show that only CD at 220 nm is relevant to observe the unfolding of an alpha helix whereas no change is observed for CD at 204 nm. Conversely, both absorptions yield information on the dynamics of the process.     

Molecular Recognition of Parallel DNA Quadruplex d(TTAGGGT)4 by Mitoxantrone: Binding with 1:2 Stoichiometry Leading to Thermal Stabilization and Telomerase Inhibition

The interaction of the anthraquinone derivative mitoxantrone, a semisynthetic anti‐cancer drug with two non‐planar side chains, with heptamer G‐quadruplex d(TTAGGGT)₄, which contains the human telomere DNA sequence, was evaluated by differential scanning calorimetry, fluorescence Job plotting, absorption, and NMR and CD spectroscopy. Binding led to thermal stabilization of DNA (ΔT_m=13–20 °C). The spectra revealed that two mitoxantrone molecules bind externally at two sites of the DNA quadruplex as monomers, by partial insertion of the chromophore and side‐chain interaction at the grooves. The inhibition of telomerase (IC₅₀=2 μm), as determined by a TRAP assay, can be attributed to thermal stabilization of the DNA quadruplex because of the interactions with mitoxantrone. The studies revealed highly specific molecular recognition between a ligand and a parallel‐stranded G‐quadruplex; this might serve as a platform for the rational design of new drugs.     

水杨醛缩邻甲苯胺Schiff碱及其Zn(Ⅱ)配合物的合成与表征

由水杨醛和邻甲苯胺缩合形成的不对称Sch iff碱与Zn(Ⅱ)盐反应得到了金属配合物。通过元素分析、红外光谱、紫外-可见光谱、核磁共振氢谱(1H NMR)及13C谱(13C NMR)等分析测试手段对配体及其配合物进行了结构表征,确定了配合物的可能结构,结果表明,配体通过N,O原子与金属离子配位。     

Novel approach for attapulgite/poly(acrylic acid) (ATP/PAA) nanocomposite microgels as selective adsorbent for Pb(II) Ion

A novel approach was developed for the preparation of the attapulgite/poly(acrylic acid) (ATP/PAA) nanocomposite microgels via the “one-pot” inverse suspension radical polymerization of acrylic acid (AA) with the multi-functionalized attapulgite nanorods (org-ATP) as the sole crosslinker. The parameters of the feeding ratio of the functional attapulgite (org-ATP) nanorods and AA (org-ATP/AA), oil (liquid paraffin)–water ratio, and feeding ratios of dispersing agent (sodium dodecyl benzene sulfonate (SDBS)) and initiator (ammonium persulfate (APS)) were optimized via 4-Variable 3-Level Orthogonal experiments. Under the optimized preparation condition, more than 85% of the monomer AA had been grafted onto the org-ATP nanorods to form the 3-dimensional network of the ATP/PAA nanocomposite microgel. The ATP/PAA nanocomposite microgel exhibited better mechanical stabilities (resistance to pressure and resistance to agitation) and selective adsorption to heavy metal ions, especially to Pb²⁺. The adsorbed Pb²⁺ ion could be completely eluted with HCl solution. The better mechanical stability and regeneration make it potential adsorbent for the heavy metal contaminated water.     

Synthesis,Structure and Fluorescence Spectra Study of a Supramolecular Zinc(II) Complex

A new structural supramolecular zinc(II) complex (1), [Zn(H₂O)₆]²⁺[Zn(4,4′-bipy)(SO₄)₂(H₂O)₂]^2?[Zn(4,4′-bipy)(SO₄)(H₂O)₃] is synthesized in mixed solvent system at room temperature. The complex was characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. Structural analyses reveal that the complex is crystallized in the triclinic system with P1 space group. Cell parameters: a = 7.3145 (15) Å, b = 11.194 (2) Å, c = 11.442 (2) Å, α = 72.48 (3)°, β = 73.78 (3)°, γ = 83.39 (3)°, V = 857.3 (3) ų. Zn atoms (Zn1, Zn2 and Zn3) are all six-coordinated, however, the coordination environments of them are different. Owning to the abundant intro- and inter- hydrogen bonding interactions, the adjacent molecular units were connected to form a 2D supramolecular chain, and the two adjacent chains were furthermore linked to form a 3D supermolecular network structure via the hydrogen bonds. In addition, it is found that the complex has potential applications as fluorescent-emitting materials due to the strong fluorescence.     

Synthesis of a Novel Macroporous Silica-Calix[4]arene-Crown Supramolecular Recognition Material and its Adsorption for Cesium and some Typical Metals in Highly Active Liquid Waste

Abstract

A novel macroporous silica-based 25,27-bis(iso-propyloxy)calix[4]arene-26,28-crown-6 (BiPCalix[4]C6) supramolecular recognition material, BiPCalix[4]C6/SiO₂-P, was synthesized. It was prepared by impregnation and the immobilization of the BiPCalix[4]C6 molecule into the pores of the macroporous SiO₂-P particles. The adsorption of Cs(I) and some typical elements Na(I), K(I), Rb(I), Sr(II), Ba(II), Ru(III), Mo(VI), La(III), and Y(III) onto the BiPCalix[4]C6/SiO₂-P material was investigated. The effects of the HNO₃ concentration, contact time, and temperature on the adsorption of the tested metals were studied. It was found that at the optimum concentration of 3.0 M HNO₃, BiPCalix[4]C6/SiO₂-P exhibited excellent adsorption ability and high selectivity for Cs(I) over all the tested elements, which showed weak or almost no adsorption except Rb(I). A pseudo-second-order model was found to be able to describe the adsorption kinetics of Cs(I). The chemical complexation of Cs(I) with BiPCalix[4]C6/SiO₂-P was considered to be the rate-controlling step. Meanwhile, the thermodynamic parameters of the Cs(I) adsorption, ΔH?, ΔG?, and ΔS? were determined. The adsorption of Cs(I) onto BiPCalix[4]C6/SiO₂-P was exothermic. It was demonstrated that in 3.0 M HNO₃, the novel macroporous BiPCalix[4]C6/SiO₂-P material shows promise for the partitioning of Cs(I) from highly active liquid waste.     

Sn(IV)-Porphyrin-Based Nanostructures Featuring Pd(II)-Mediated Supramolecular Arrays and Their Photocatalytic Degradation of Acid Orange 7 Dye

Two robust Sn(IV)-porphyrin-based supramolecular arrays (1 and 2) were synthesized via the reaction of trans-Pd(PhCN)₂Cl₂ with two precursor building blocks (SnP¹ and SnP²). The structural patterns in these architectures vary from 2D to 3D depending on the axial ligation of Sn(IV)-porphyrin units. A discrete 2D tetrameric supramolecule (1) was constructed by coordination of {(trans-dihydroxo)[5,10-bis(4-pyridyl)-15,20-bis(phenyl) porphyrinato]}tin(IV) (SnP¹) with trans-PdCl₂ units. In contrast, the coordination between the {(trans-diisonicotinato)[5,10-bis(4-pyridyl)-15,20-bis(phenyl)porphyrinato]}tin(IV) (SnP²) and trans-PdCl₂ units formed a divergent 3D array (2). Axial ligation of the Sn(IV)-porphyrin building blocks not only alters the supramolecular arrays but also significantly modifies the nanostructures, including porosity, surface area, stability, and morphology. These structural changes consequently affected the photocatalytic degradation efficiency under visible-light irradiation towards acid orange 7 (AO) dye in an aqueous solution. The degradation efficiency of the AO dye in the aqueous solution was observed to be between 86% to 91% within 90 min by these photocatalysts.