Controllable Coordination Self‐Assembly Based on Flexibility of Ligands: Synthesis of Supramolecular Assemblies and Stimuli‐Driven Structural Transformations

Coordination self‐assemblies have attracted more and more attentions from chemists because of their beautiful structures and wide applications, and a number of excellent reviews that focus on either synthesis or application have been published. This paper will hightlight how to controllablly construct supramolecular assemblies based on flexibility of ligands driven by different external stimuli. Herein, not only various discrete metal‐organic aggregates including M₂L₂ type metallocycles, M₂L₄/M₂L₆/M₃L₂/M₆L₄/M₆L₈ type metallocages have been prepared, but also many well‐organized ensembles based on such new‐formed discrete aggretates have been further assembled driven by suitable external stimuli. Also, controllable self‐assembly processes accompanied with structure changes have been developed. It is expected that this paper will provide a potential strategy for developing novel coordination assemblies that can be comparable to biomacromolecules from organism.     

不同微乳液体系和微乳液凝胶中的酶催化反应

在缔合胶体中表面活性剂、有机相、助表面活性剂的选择及含不量、缓冲溶液pH值对微乳液中酶催化活性均有影响。油包水微乳液中的酶催化反应可用来模拟细胞微环境。中相微乳液中的酶催化反应既可提高酶转化率又对产物的分离提供方便,而明胶包埋的微乳液凝胶中固定化酶的催化反应则在产物的分离和酶的重复利用方面有其优点,可用于制备有机合成及手性化合物的拆分。     

Coordination‐Driven Self‐Assembly of Functionalized Supramolecular Metallacycles: Highlighted Research during 2010–2018

During the past few decades, the construction of macrocyclic molecules/complexes has attracted considerable attention because of their wide applications in sensing, catalysis, molecular machine, drug delivery, etc. Coordination‐driven self‐assembly has proven to be a simple yet highly efficient approach for the preparation of various supramolecular metallacycles with the predetermined shapes and sizes as well as the distribution and total number of functional groups. Since the significant progress has been made during the last few years in the field of coordination‐driven self‐assembly, it is time to summarize the recent development in coordination‐driven self‐assembly of functionalized supramolecular metallacycles. In this review, we will highlight some recent advances concerning the preparation of functionalized supramolecular metallacycles via coordination‐driven self‐assembly between the year 2010–2018. In addition, the properties and the applications of these metallacycles in the areas of photo‐ and electrochemistry, sensing, supramolecular gel, biological applications, etc. will be also discussed.     

Depth and width of cured lines in photopolymerizable ceramic suspensions

When a photopolymerizable ceramic suspension is illuminated, the cured region is characterized by the cure width and cure depth. The cure depth follows a semilogarithmic behavior with increasing energy dose, as expected for Beer–Lambert absorption, and is described by the depth sensitivity (S_d) and depth critical energy dose (E_d). The excess cure width, which is the cured width beyond the incident illumination width, is also found to increase with the logarithm of energy dose. This quasi-Beer–Lambert behavior can be described by a width sensitivity (S_w) and width critical energy dose (E_w). The semilogarithmic dose dependence is demonstrated for ceramic suspensions containing silica, mullite, alumina, and zircon powders. Broadening can be quantified by the broadening depth (D_b), which is the cure depth at which broadening begins to occur. It is shown that the broadening depth decreases with the logarithm of the normalized refractive index contrast between the powder and monomer solution.     

多组分反应合成香豆素衍生物的研究进展

综述了近几年多组分反应合成香豆素衍生物的研究进展,详细介绍了不同底物参与的反应所需的条件,产率和机理研究,并对其发展方向加以展望。     

Supramolecular Cationic Assemblies against Multidrug-Resistant Microorganisms: Activity and Mechanism of Action

The growing challenge of antimicrobial resistance to antibiotics requires novel synthetic drugs or new formulations for old drugs. Here, cationic nanostructured particles (NPs) self-assembled from cationic bilayer fragments and polyelectrolytes are tested against four multidrug-resistant (MDR) strains of clinical importance. The non-hemolytic poly(diallyldimethylammonium) chloride (PDDA) polymer as the outer NP layer shows a remarkable activity against these organisms. The mechanism of cell death involves bacterial membrane lysis as determined from the leakage of inner phosphorylated compounds and possibly disassembly of the NP with the appearance of multilayered fibers made of the NP components and the biopolymers withdrawn from the cell wall. The NPs display broad-spectrum activity against MDR microorganisms, including Gram-negative and Gram-positive bacteria and yeast.     

Solid-state synthesis and characterisation of mesoporous zirconia with lamellar and wormhole-like mesostructures

Mesostructured zirconia with lamellar and wormhole-like mesostructure was synthesized using a solid-state reaction route. Ordered lamellar mesostructure is achieved at low OH⁻/Zr ratio; while high OH⁻/Zr ratio leads to less ordered wormhole-like mesostructure. The varying synthesis conditions result in different inorganic frameworks with amorphous (in lamellar mesostructure) or tetragonal phase pore walls with different thermal stability. The surface area and pore structure of zirconia prepared by this method can be tailored using simple synthesis parameters such as OH⁻/Zr ratio and crystallization temperature. High surface area up to 716 m²/g can be achieved in the lamellar structured zirconia. However, the wormhole-like structured zirconia possesses high thermal stability. The results strongly suggest that in solid-state synthesis system mesostructure formation still follows the supramolecular self-assembly mechanism. In such synthesis system, the lamellar and reverse hexagonal structure can be transformed at different OH⁻/Zr ratios in order to minimize the surface energy of the mesophases formed.     

超分子自组装及其在高分子合成领域中的应用

超分子自组装是近年来倍受重视的国际前沿课题,它将会极大促进信息、能源、生命、环境和材料科学等学科领域的发展,介绍了基于氢键、π键、配位键、双亲分子4种自组装体系,重点综述了这4种自组装体系在高分子合成领域中的最新进展,最后对超分子自组装的发展趋势做了展望。     

茚三酮参与的多组分反应合成螺杂环化合物的研究进展

茚三酮代替芳香醛参与多组分反应合成螺杂环化合物的研究进展还未见文献报道.鉴于此,为了更好地了解这方面的最新动态,综述了2005年以来利用茚三酮代替芳香醛参与多组分反应来合成相关螺吡喃化合物的研究进展,主要涉及茚三酮与丙二腈和环酮的多组分反应、茚三酮与两分子β-二酮的多组分反应、茚三酮、茚二酮与萘胺的多组分反应、茚三酮、肌氨酸与其它底物的多组分反应以及茚三酮与苯肼和芳香醛的三组分反应。同时对其发展方向加以展望。     

De Novo Design of Polyhedral Protein Assemblies: Before and After the AI Revolution

Self-assembling polyhedral protein biomaterials have gained attention as engineering targets owing to their naturally evolved sophisticated functions, ranging from protecting macromolecules from the environment to spatially controlling biochemical reactions. Precise computational design of de novo protein polyhedra is possible through two main types of approaches: methods from first principles, using physical and geometrical rules, and more recent data-driven methods based on artificial intelligence (AI), including deep learning (DL). Here, we retrospect first principle- and AI-based approaches for designing finite polyhedral protein assemblies, as well as advances in the structure prediction of such assemblies. We further highlight the possible applications of these materials and explore how the presented approaches can be combined to overcome current challenges and to advance the design of functional protein-based biomaterials.     

Poly(N-phenylmaleimides) bearing chiral oxazolinyl pendant: Supramolecular aggregation and enantioselectivity in fluorescence response

N-Phenylmaleimide derivatives bearing a chiral oxazoline substituent at the benzene ring (N-[o-(4,5-dihydro-1,3-oxazol-2-yl)phenyl]maleimides, OPMIs) were polymerized using a binary initiating system composed of Et₂Zn and n-BuLi to in situ produce the zinc complexes of optically active poly(OPMI)s. The significant changes in chiroptical and fluorescent properties were observed for these polymers upon complexation with metal ions due to the formation of supramolecular structure, evidenced by circular dichroism, fluorescence spectrum and atomic force microscopy. The fluorescence spectra of poly(OPMI)/Zn^II complexes in the presence of (R)/(S)-1,1′-bi-2-naphthol (BINOL) and (R)/(S)-2-amino-1-propanol were studied in THF media. It was found that the fluorescence intensity of the complexes responded differently to both enantiomers of BINOL and the amino alcohol in a quenching and enhancement fashion, respectively. Furthermore, the enantioselective fluorescence response was strongly dependent on the amount of incorporated zinc in polymer matrices.     

Colloidal Fluorophore Aggregates for the Selective Detection of Albumins in Solution and on Electrophoresis Gels

We report a fluorescent probe that is highly sensitive and selective for serum albumins. Signal transduction results from the disassembly of fluorescence-quenched aggregates upon binding to human serum albumin (HSA). The probe offers a rapid (≤2 s) fluorometric assay of HSA in phosphate-buffered saline, urine, or blood serum with a high signal-to-noise ratio. It is also useful as a wash-free prestaining reagent for detecting HSA on electrophoresis gels.     

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.     

硫酸氢钠在催化反应中的应用

介绍了近年来硫酸氢钠在催化酯化和催化缩合反应中的应用 ,指出反应机理研究和开拓其应用领域是今后的研究方向     

低热固相合成磷酸铵铜微肥及信噪比控制合成

对合成缓溶磷酸铵铜多元微肥的新方法进行了研究,以聚乙二醇-400 （PEG-400）为模板,CuSO4•5H2O和(NH4)3PO4•3H2O为原料,用低热固相反应一步法成功合成得到磷酸铵铜。用产物XRD图谱数据计算得到的信噪比作为试验的考察指标,试验中应用了均匀设计试验法及数据挖掘技术,在数据挖掘成果的指导下进行了试验。试验结果表明,用最优工艺条件合成得到的产物为51nm的NH4CuPO4 ∙H2O。该合成方法除了得到微溶的磷酸铵铜外,还得可溶的硫酸铵或者硫酸氢铵,这些产物均是肥料,故在实际应用中,用本文的合成法合成磷酸铵铜微肥时,无需分离,其产物混合物就可以作为肥料作用了,不仅合成的工艺甚为简洁,而且生产过程没有废水的产生,无论是从工艺上,还是环保上均比液相法具有优势,是一种颇具工业应用前景的合成法。     

低热固相合成磷酸镧及其结晶度

对合成功能材料磷酸镧的新方法进行了研究,以聚乙二醇-400 （PEG-400）为表面活性剂,LaNO₃•6H₂O和(NH₄)₃PO₄•3H₂O为原料,用低热固相反应法成功合成得到磷酸镧。用产物XRD图谱数据计算得到的结晶度作为试验的考察指标,试验中应用了均匀设计试验法及数据挖掘技术,在数据挖掘成果的指导下进行了试验。试验结果表明,用最优工艺条件合成得到的产物为23nm的LaPO₄∙0.5H₂O,结晶度为97.8%与数据挖掘得到的最佳结果相吻合。TG/DTA分析结果表明LaPO₄∙0.5H₂O在300℃下加热脱水可以转变成为LaPO₄。     

Progress in the Preparation of Functional and (Bio)Degradable Polymers via Living Polymerizations

This review presents the latest developments in (bio)degradable approaches and functional aliphatic polyesters and polycarbonates prepared by typical ring-opening polymerization (ROP) of lactones and trimethylene carbonates. It also considers several recent innovative synthetic methods including radical ring-opening polymerization (RROP), atom transfer radical polyaddition (ATRPA), and simultaneous chain- and step-growth radical polymerization (SCSRP) that produce aliphatic polyesters. With regard to (bio)degradable approaches, we have summarized several representative cleavable linkages that make it possible to obtain cleavable polymers. In the section on functional aliphatic polyesters, we explore the syntheses of specific functional lactones, which can be performed by ring-opening copolymerization of typical lactone/lactide monomers. Last but not the least, in the recent innovative methods section, three interesting synthetic methodologies, RROP, ATRPA, and SCSRP are discussed in detail with regard to their reaction mechanisms and polymer functionalities.     

室温固相法合成ZnCO3及其自晶化特征

以ZnSO4×7H2O与NH4HCO3为原料,聚乙二醇-400为模板剂,经室温固相反应合成得到了ZnCO3纳米晶体,其粒径为25 nm左右. 实验结果表明,在始终保持NH4HCO3过量的条件下可抑制杂质的形成,得到结晶完好的ZnCO3纳米晶体;在研磨反应的20 min内,产物ZnCO3已自动晶化成为完好的晶体,无需静置晶化,长时间的静置晶化反而会导致副产物碱式碳酸锌的生成;模板剂对产物组成具有重要的调控作用,有模板剂时得到的是ZnCO3纳米晶体,无模板剂时得到的是含有碱式碳酸锌与ZnCO3的混合物,但以碱式碳酸锌为主. 与文献报道的微乳液法相比,可知模板剂是通过与反应物释放出来的结晶水在研磨搅拌作用下形成微乳液体系,从而对产物组成进行调控.     

Impact of Carbon Dioxide Pressurization on Liquid Phase Organic Reactions: A Case Study on Heck and Diels–Alder Reactions

Heck coupling reactions of methyl acrylate with various aryl bromides have been investigated using a Pd/TPP catalyst in toluene under pressurized CO₂ conditions up to 13 MPa. Although CO₂ is not a reactant, the pressurization of the reaction liquid phase with CO₂ has positive and negative impacts on the rate of Heck coupling depending on the structures of the substrates examined. In the case of either 2‐bromoacetophenone or 2‐bromocinnamate, the conversion has a maximum at a CO₂ pressure of about 3 MPa; for the former, it is much larger by a factor of 3 compared with that under ambient pressure. For 2‐bromobenzene, in contrast, the conversion is minimized at a similar CO₂ pressure, being half compared with that at ambient pressure. In the other substrates, including the other isomers of these three aryl bromides, the conversion simply decreases or does not change so much with the CO₂ pressure. To examine the factors responsible for the effects of CO₂ pressurization, the phase behavior and the molecular interactions with dense phase CO₂ have also been studied by visual observation and in situ high pressure FT‐IR spectroscopy. In addition, impact of CO₂ pressurization was also studied for the Diels–Alder reactions of isoprene with a few dienophiles like methyl acrylate, methyl vinyl ketone, and acrolein in the same solvent, toluene, but a heterogeneous silica‐alumina catalyst was used (the reaction system was liquid‐solid biphasic). When the CO₂ pressure is raised, the conversion monotonously decreases for the three dienophiles; however, the product selectivity changes with the pressure, in particular for acrolein. The FT‐IR spectroscopic measurements suggest that its reactivity is altered by interactions with CO₂ molecules under pressurized conditions.     

纤维状碱式碳酸铝铵的固相合成及其热解的自粉碎特征

在钠、镁离子的调控下,用室温固相反应法合成得到了纤维状的碱式碳酸铝铵(AACH),产物结晶度较好,长度约20～30μm。该纤维状的AACH在高温裂解得到的氧化铝仅为60nm左右的晶体。在长度上,氧化铝只是前驱体纤维状AACH的五百分之一左右,说明AACH在高温裂解时经历了猛烈的"爆炸",自行粉碎成纳米级的小碎块,碎块完全分解后得到60nm左右的氧化铝晶体。这种自粉碎的良好特征,使其成为制备纳米氧化铝的一个重要的前驱体。