基于无铜点击反应的水凝胶合成

水凝胶是一种交联高分子材料, 在药物传输、传感器技术、组织工程中发挥重要作用。通过高效率和高精确度的点击反应合成水凝胶, 具有快速、模块化以及副反应少等优点, 并且能够得到近乎理想的网络结构。Cu（Ⅰ） 催化的叠氮-炔之间的环加成 （CuAAC） 反应作为点击反应的典型代表, 已广泛应用于水凝胶的制备。但由于该反应在制备水凝胶的过程中使用了Cu（Ⅰ） 催化剂, 导致产品易被金属铜盐污染, 从而使该反应在其制备领域受到限制。基于此, 无铜点击反应,如巯基-烯/炔反应、呋喃/蒽-马来酰亚胺 （MI） 修饰的 Diels-Alder 环加成 （D-A） 反应以及环张力促进的叠氮-炔环加成反应 （SPAAC） 已经被应用到水凝胶的制备以及功能化方面。本文就近年来上述无铜点击反应在水凝胶合成及功能化方面的应用进行综述, 并对其发展趋势进行展望。     

机体所需营养物质、微量元素及金属盐类之间的药物相互作用

列举了部分机体所需营养物质、微量元素及金属盐类之间的药物相互作用，为临床使用提供了参考。     

三核过渡金属配合物在催化反应中的研究进展

多核过渡金属配合物作为一类广泛应用的均相催化剂,其设计灵感往往来自天然酶的多金属活性位点所发挥的重要作用.目前,三核金属配合物作为活化小分子的多金属催化剂受到了广泛的关注.为深入理解三核过渡金属配合物在催化反应中作用特点,对近年报道的代表性三核过渡金属配合物按金属中心进行分类,并对配体环境形成特点及催化应用进行综述.从金属中心出发,讨论了三核过渡金属配合物的几何结构和电子特征;从配体环境出发,总结了关联三个独立的金属位点的配位环境特征;在催化应用方面,重点综述了三核过渡金属配合物在涉及特定化学键活化反应的催化作用机制,最后对三核过渡金属配合物的催化应用前景进行展望.     

聚乙二醇200基硝苯柳胺与钥孔戚血蓝蛋白的相互作用

采用荧光光谱、紫外吸收光谱和圆二色谱(CD)研究了聚乙二醇200基硝苯柳胺与钥孔戚血蓝蛋白(KLH)的相互作用。结果表明,聚乙二醇200基硝苯柳胺对KLH的荧光猝灭机制属于静态猝灭;由Lineweaver-Burk方程计算出不同温度下结合常数K,由Van’t Hoff方程计算出△H和△S平均值,结合力主要为静电作用力;根据F rster非辐射能量转移机制求得给体与受体间的结合距离r=5.76 nm;同步荧光光谱表明,聚乙二醇200基硝苯柳胺能够被KLH存储和转运,但结合时对蛋白的构象有一定的影响;圆二色光谱的数据表明相互作用后KLH的二级结构发生了改变:KLH的α-螺旋的含量从43.1%下降到37.8%。     

Reactions of Metal Salts and Alkali Metal Nitrates. Role of the Metal Precursors and Alkali Metal Ions in the Resulting Phase of Zirconia

Zirconia powders are prepared by reaction of a zirconium precursor with an alkali metal nitrate. The major part of the reactions takes place before the melting points and then the reactions go slowly to completion at 450°C in the molten salts. The roles of the precursor and the alkali metal ion are discussed considering the reaction between two precursors, octahydrated zirconium oxychloride and zirconium tetrachloride, and two nitrates, LiNO₃ and NaNO₃, and some resulting physico-chemical differences. The obtained zirconia powders contain very small amounts of alkali metal ions which act as stabilizing agent. Their effect on the balance tetragonal-monoclinic ZrO₂ depends upon the homogeneity of their distribution which is related to their ability to diffuse inside the bulk of particles and their polarizing power when located mainly on the surface.     

氯硝柳胺及其衍生物与钥孔戚血蓝蛋白的相互作用

以氯硝柳胺为原料合成了聚乙二醇200基氯硝柳胺. 采用荧光光谱、同步荧光光谱、紫外吸收光谱和圆二色谱研究了氯硝柳胺及其衍生物与钥孔戚血蓝蛋白(KLH)的相互作用. 结果表明, 两种药物分子对KLH的荧光猝灭机制属于静态猝灭; 由Lineweaver-Burk方程计算出不同温度下结合常数K, 但是聚乙二醇200基氯硝柳胺与KLH的作用相对较弱; 由Van′t Hoff方程计算出ΔH和ΔS平均值, 结合力主要为静电作用力; 热力学函数计算结果表明, 氯硝柳胺及其衍生物与KLH的作用过程是一个熵增加、Gibbs自由能降低的自发分子间作用过程; 根据Förster非辐射能量转移机制求得给体与受体间的结合距离r均小于7 nm; 同步荧光光谱表明, 氯硝柳胺及其衍生物能够被血蓝蛋白存储和转运, 但结合时对蛋白构象有一定影响; 圆二色谱测得加入两种药物后, KLH的α-螺旋含量均降低, 二级结构发生改变. 通过比较氯硝柳胺及其衍生物与KLH的相互作用, 初步探讨了分子结构与其结合能力之间的联系.     

Studies of the Interaction Between Ciprofloxacin and the Hemocyanin From Chinese Mitten Crab Eriocheir Japonica Sinensis

The interactions between ciprofloxacin and hemocyanin were investigated by ultraviolet-vis absorbance, circular dichroism, and fluorescence spectra techniques. The ciprofloxacin effectively quenched the intrinsic fluorescence of hemocyanin via static quenching. There is only one class of binding site at the interface of hemocyanin. The hydrophobic and electrostatic interactions played a major role in the binding process of ciprofloxacin-hemocyanin system. The distance between the tryptophan residues and ciprofloxacin was calculated using F?rster theory to be 3.859 nm. The alteration of the environment of tryptophan residues and the secondary protein structure in the presence of the ciprofloxacin was confirmed by circular dichroism, synchronous, and three-dimensional fluorescence spectra.     

Synthesis and Characterization of a Novel Phosphonate Metal Organic Framework Starting from Copper Salts

Abstract

Increased interest in the area of metal phosphonate inorganic–organic frameworks is exemplified with a high range of applications and a rich synthetic and structural chemistry of these compounds. The synthesis and potential applications of a novel metal phosphonate, namely Cu(II) phenylvinylphosphonate (PVP) is described in this paper. Syntheses were performed starting from a 1:1 molar ratio of a Cu(NO₃)₂·6H₂O or CuSO₄·5H₂O and 1-phenylvinylphosphonic acid under hydrothermal conditions at pH values ranging between 2.8 and 3.1. The influence of different counterion for the copper salt used as the Cu(II) source on the structure and crystallinity of the final product was studied. The obtained copper(II) phenylvinylphosphonate compounds were characterized by X-ray powder diffraction, FT-IR spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectrometry (EDAX). A possible crystal structure for the copper (II) phenylvinylphosphonate products is proposed using semiempirical approaches.     

Disilane Cleavage with Selected Alkali and Alkaline Earth Metal Salts

The industry-scale production of methylchloromonosilanes in the Müller–Rochow Direct Process is accompanied by the formation of a residue, the direct process residue (DPR), comprised of disilanes Me_nSi₂Cl_6-n (n=1–6). Great research efforts have been devoted to the recycling of these disilanes into monosilanes to allow reintroduction into the siloxane production chain. In this work, disilane cleavage by using alkali and alkaline earth metal salts is reported. The reaction with metal hydrides, in particular lithium hydride (LiH), leads to efficient reduction of chlorine containing disilanes but also induces disproportionation into mono- and oligosilanes. Alkali and alkaline earth chlorides, formed in the course of the reduction, specifically induce disproportionation of highly chlorinated disilanes, whereas highly methylated disilanes (n>3) remain unreacted. Nearly quantitative DPR conversion into monosilanes was achieved by using concentrated HCl/ether solutions in the presence of lithium chloride.     

Interaction of Triosmium Complexes with Hydrogen Chloride: A Model for Fine-Tuning Regioselective Protonation in Metal Clusters

The reaction of Os₃(CO)₁₀(CNR)(NCMe) (1) with HCl was studied and this system was found to be a good model for observing the fine-tuning of site-selective protonation in metal complexes. Three products including the protonated species [(-H)Os₃(CO)₁₀(CNR)(NCMe)]⁺Cl^– (2), the bridging aminocarbyne complex (µ-Cl)Os₃(CO)₁₀(µ₂-C = NHR) (3), and the hydrido derivative (-H)Os₃Cl(CO)₁₀(CNR) (4) were obtained for the reaction. The site of protonation, either on the Os center or on the nitrogen atom of coordinated isocyanide, was tuned in a sensitive manner by the nature of the coordinated isocyanides, the polarity of the solvents, and the strengths of the acids, leading to different product distributions. The more electron withdrawing isocyanides (CNCH₂Ph, CNPh) favor the formation of the aminocarbyne complex 3. In a nonpolar solvent like cyclohexane the reaction afforded 3 as the main product. Furthermore, complex 2 was converted to (-H)Os₃(CO)₁₀(₂-CONHR) (5) upon hydrolysis, in which the coordinated isocyanide was transformed to a carboxamido group. This was verified by obtaining the deuterated species (-H)Os₃(CO)₁₀(₂-CONDPr) when [(-H)Os₃(CO)₁₀(CNPr)(NCMe)]⁺Cl^– (2a) was treated with D₂O in THF. The molecular structures of (µ₂-Cl)Os₃(CO)₁₀(µ₂-C = NHCH₂Ph) (3b) and (-H)Os₃Cl(CO)₁₀(CNPr) (4a) were determined by X-ray diffraction analyses. Complex 3b contains both bridging chloride and bridging aminocarbyne groups, whereas 4a contains a terminal chloride, a terminal isocyanide and a bridging hydride.     

Thermal Decomposition Kinetics of Some Metal Complexes of N,N-diethyl-n '-benzoylthiourea

Thermogravimetry (TG) and differential thermal analysis (DTA) were performed on the complexes with general formula (M(DEBT)_n (where M =Fe, Co, Ni, Cu or Ru; n =2, or 3 and DEBT=N,N-diethyl-N'-benzoylthiourea). Derivative thermogravimetric (DTG) curves were also recorded in order to obtain decomposition data on the complexes. The complexes of Fe(III), Co(II), Ni(II), Cu(II) and Ru(III) displayed two- or three-stage decomposition patterns when heated in a dynamic nitrogen atmosphere. Mass loss considerations relating to the decomposition stages indicated the conversion of the complexes to the sulfides or to the corresponding metal alone (Cu, Ru, NiS, CoS or FeS). Mathematical analysis of the TG and DTG data showed that the order of reaction varied between 0.395 and 0.973. Kinetic parameters such as the decomposition energy, the entropy of activation and the pre-exponential factor are reported. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hydrothermal Synthesis of Three New Transition Metal Complexes with Azido Ligands

Hydrothermal reactions of NaN₃, 1, 10‐phenanthroline or 2, 2′‐bipyridine and transition metal cations including Zn^II or Co^II in basified aqueous solutions yielded the three complexes, [Zn₂(bipy)₂(N₃)₄]_n ( 1 ), [Zn(phen)(N₃)₂]_n ( 2 ), and [Co(phen)₂(N₃)₂] ( 3 ), which were characterized by X‐ray crystallography. All three complexes crystallize in the triclinic system, space group P1¯, with a = 6.5506(2), b = 10.8441(6), c = 16.893(2)Å, α = 96.333(5), β = 95.361(7), γ = 90.548(6)° for 1 ; a = 7.0302(10), b = 10.0590(14), c = 10.4550(15)Å, α = 109.372(2), β = 103.980(2), γ = 106.137(2)° for 2 ; and a = 8.1722(2), b = 11.0332(3), c = 12.5066(2)Å, α = 82.681(8), β = 82.457(9), γ = 72.991(7)° for 3 , respectively. The photoluminescence spectra for compounds 1 and 2 have also been studied.     

Characterization of Hollow Chemical Garden Fibers from Metal Salts and Water Glass

Hollow fibers formed from water glass and metal salts of IIA(Ca), VIIB(Fe, Co, Ni) and IB(Cu) groups were characterised in this study. Fragile fibres obtained herein broke down into small pieces during isolation and drying. Quantitative information about morphology, chemical composition and surface structure of the fibres were obtained. The diameter and wall thickness of the fibers were around 50 and 3 . respectively. They had particulate inner and smooth outer surfaces. Fibers had variable composition with metal (II) oxide/SiO₂ ratio in the range 0.31 to 1.02. While group VIIB metal (II) fibres were amorphous, group IIA and IB metal (II) fibres were partially crystalline All the fibres had pores both in micro pore and meso pore region. The B.E.T surface area from N₂ adsorption data was in the range of 10–249 m³ g^–1 and 8–176 m² g^–1 from Langmuir and B.E.T models respectively.     

Metal chelates with some cellulose derivatives; part IV. Structural chemistry of HEC complexes

Reactions of hydroxyethyl cellulose (HEC) with Cr ^III, Ni^II, Co^II, or Cu^II chlorides in aqueous medium yielded complexes with formulae [M(HEC)Cl _m .n H ₂O], wherem =1 or 2 and n=2 or 3. HEC acted as a uninegatively charged bidentate ligand in the case of Cr^III and Ni^II, and as a neutral ligand in the case of Co^II and Cu^II complexes. The spectra showed that the binding sites in Cr^III and Ni^II complexes were the ether oxygen between two ethoxyl groups and the oxygen of the hydroxyl group; while in the Co^II and Cu^II complexes the binding sites were the oxygen of ethoxyl groups and the primary alcoholic O atom of glucopyranose rings. These complexes would most likely exhibit octahedral geometry with Cr^III, Ni^II, and Co^II, but square planar configuration in the case of the Cu^II complex. The ligand parameters of the Cr^III, Ni^II, and Co^II metal chelates were calculated in different solvents and at different temperatures. The thermal stability of the above complexes was investigated and the overall thermodynamics functions G⁰, H⁰, and S⁰, associated with complex formation, were estimated.     

几种稀土盐封闭的铝阳极氧化试样的腐蚀行为

为提高铝硫酸阳极氧化膜的抗污染和防腐蚀性能，分别采用环境友好的铈盐、钇盐和镧盐溶液对阳极氧化膜进行了封闭处理。采用动电位极化法比较了不同稀土盐封闭的铝阳极氧化试样在弱酸性NaCl腐蚀介质中的电化学行为，采用扫描电子显微镜（SEM）和能量色散谱（EDS）对封闭试样腐蚀前后的表面形貌、组成进行了表征。结果表明：在腐蚀介质的侵蚀及强电化学极化条件下，铈盐和镧盐封闭的阳极氧化膜对铝基体具有较好的保护作用，而钇盐封闭膜的保护作用则较差。这种差别的主要原因是不同稀土盐封闭过程中封闭产物的析出倾向及速率不同。     

多柔比星稀土金属离子配合物与DNA相互作用的研究

用紫外分光光度法和荧光光谱法研究了多柔比星( Adriamycin,ADM)稀土金属离子配合物(ADM-M)与DNA的相互作用.结果发现,在pH=7.0时,ADM与Eu3+、yb3+能形成稳定配合物,该配合物可使DNA的最大吸收产生明显的减色效应及红移,并能够竞争置换溴化乙锭(EB)与DNA的结合点.KI猝灭试验发现D...     

Metal Ion Removal from Aqueous Solution by Liquid Phase Polymer-Based Retention Technique

Summary: Water-soluble poly[3-(dimethylamino)propylacrylate] is synthesized by radical polymerization with a yield of 87%. The polymer structure is confirmed by FT-IR and ¹H-NMR spectroscopies. The polymer lost only 3% of weight up to 100 °C. The narrowest molecular weight distribution is observed with the fraction between 3,000 and 10,000 Da. P(DAPA) presents a high affinity for the metal ions Pb²⁺ and Cu²⁺, while the other metal ions are not significantly retained. By increasing the filtration factor, Z, metal ion affinity decreases, indicating a very weak ligand-metal interaction and the possibility of its destruction when washed with water at the filtration cell's pH. For Z = 10, the retention values of Pb²⁺ and Cu²⁺ at pH 5 are 76.5% and 48.5%, respectively, while the values for Cu²⁺ and Cd²⁺ at pH 7 are 89.5% and 40.4%, respectively.     

过渡金属配合物催化炔烃和亲核试剂的羰化反应

羰化反应(氢甲酰化反应、羰化羧酸化反应、羰化酯化反应、羰化酰胺化反应等)是制备醛(/醇)、羧酸、羧酸酯、酰胺等高附加值含氧羰基化合物有效的途径,具有反应原子经济性高、目标羰基化合物选择性高、反应条件较氧化过程更温和可控的优势.羰化反应的原料包括烯烃、炔烃、卤代烃、醇等有机化合物.其中,在过渡金属催化剂作用下,炔烃与不同...