三维有序大孔SiO2中的纳米银

A multi-step process was used for preparation of three-dimensionally ordered macroporous (3DOM) SiO2, in which fully accessible Ag nanoparticles are incorporated. The method involves the processes of assembly of polystyrene colloidal crystal, preparation of 3DOM SiO2, and incorporation of Ag nanoparticles within 3DOM SiO2 through in situ Tollens‘ reaction. XRD, SEM and EDXS determination show that the Ag particles deposited on the macroporous walls in nano dimension. The results indicate that lower concentration of silver ammoniate and for-maldehyde in the solution is favorable for forming a very narrow size distribution and uniform shape of nanoparticles. However, the higher the concentration of the solution and the more the loading times, the larger the possibility to form un-uniform particles. Ag nanoparticles can be sintered into larger and spheral particles by calcination at 600℃, but can resist sintering owing to their high dispersivity when loading amount is small. The study provided a simple approach to tailor Ag/3DOM SiO2 composite materials with desired morphology and size of Ag particles within the macropores.     

Tetraaqua‐1κO,2κ3O‐(μ‐2,4‐dinitrophenolato‐1κ2O1,O2:2κO1)(2,4‐dinitrophenolato‐1κ2O1,O2)dilithium(I): a dinuclear lithium(I) complex

The title complex, [Li₂(C₆H₃N₂O₅)₂(H₂O)₄], contains two kinds of Li atoms, viz. five‐coordinated and four‐coordinated. The five‐coordinated Li ion has a tetragonal–pyramidal geometry, with a water molecule in the apical position and four O atoms from two 2,4‐dinitrophenolate (2,4‐DNP) ligands in the basal plane. The four‐coordinated Li ion has a tetrahedral geometry, with three water molecules and one phenolate O atom of a 2,4‐DNP ligand. The Li ions are bridged by a phenolate O atom, giving the complex a dinuclear structure. The crystal packing is stabilized by O—H...O hydrogen‐bonding interactions involving the water molecules and nitro O atoms.     

Extraction of U(VI), Th(IV) and some fission products from nitric acid medium by sulfoxides and effect of γ-irradiation on the extraction

The extracting abilities for thorium, uranium and some fission products by five sulfoxides are given. The results show that di(2-ethylhexyl) sulfoxide (DEHSO) is not only completely miscible with kerosene, but also superior to tri-n-butyl phosphate in some properties. The extraction behavior of uranium, thorium and some fission products such as zirconium, niobium and ruthenium from aqueous nitric acid with DEHSO in kerosene has been studied over a wide range of conditions. DEHSO extracted uranium and fission products better than TBP under all conditions and is similar to TBP in extraction of thorium. A study of extraction mechanism indicates that U and Th are extracted as disolvates, whereas HNO₃ is extracted as monosolvate. Extraction of the two actinides decreases with increasing temperature, indicating the extraction to be exothermic. Preliminary studies show that -ray irradiated DEHSO extracts Zr and Nb to a smaller extent than irradiated TBP in the range of 10⁴–10⁷ rad.     

Reactions of 2-amino- and 2-hydrazinobenzimidazoles with 2-acyldimedones

The reaction of 2 formyldimedone with 2-amino- and 2-hydrazinobenzimidazoles at 20°C in ethanol gave 2-(2-benzimidazolyl)aminomethylene- and 2-[2-(2-benzimidazolyl)hydrazinomethylene]-5,5-dimethylcylohex-anediones, while this reaction carried out in ethanol at reflux in the presence of acid gave 2,2-dimethyl-4-oxo 1, 2, 3, 4-tetrahydroquinazolino(1, 2-a]benzimidazole and 1-(2-benzimidazolyl)-6, 6-dimethyl-4-oxo-4, S, 6, 7-tetrahydroindazole, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–252, February, 1996.     

Theoretical Study on the Intermolecular Interactions between 1,1‐Diamino‐2,2‐Dinitroethylene and H2O

The density functional method was applied to the study of 1,1‐diamino‐2,2‐dinitroethylene (Fox‐7)/H₂O dimer. All the possible dimers ( 1, 2 and 3 ), as well as the monomers, were fully optimized with the DFT method at the B3LYP/6‐311++G^** level. The basis set superposition errors (BSSE) are 4.62, 4.07 and 3.45 kJ/mol, and the zero point energy (ZPE) corrections for the interaction energies are 7.94, 5.66 and 6.40 kJ/mol for 1, 2 and 3 , respectively. Dimer 1 is the most stable, judged by binding energy. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy of dimer 1 was predicted to be ?29.36 kJ/mol. The charge redistribution mainly occurs on the adjacent N–H··· O atoms and N–O··· H atoms between submolecules. The oxygen in the nitro group acts as a moderate hydrogen acceptor as compared to water oxygen. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities (C⁰_P), entropies (S⁰_T) and thermal corrections to enthalpy (H⁰_T), and the changes of thermodynamic properties on going from monomer to dimer over the temperature range 200.00‐700.00 K were predicted. It is energetically or thermodynamically favorable for Fox‐7 to bind with H₂O and to form dimer 1 at room temperature.     

Preparation of glucose-sensitive microcapsules with a porous membrane and functional gates

A glucose-sensitive microcapsule with a porous membrane and with linear-grafted polyacrylic acid (PAAC) chains and covalently bound glucose oxidase (GOD) enzymes in the membrane pores acting as functional gates was successfully prepared. Polyamide microcapsules with a porous membrane were prepared by interfacial polymerization, PAAC chains were grafted into the pores of the microcapsule membrane by plasma-graft pore-filling polymerization, and GOD enzymes were immobilized onto the PAAC-grafted microcapsules by a carbodiimide method. The release rates of model drug solutes from the fabricated microcapsules were significantly sensitive to the existence of glucose in the environmental solution. In solution, the release rate of either sodium chloride or VB(12) molecules from the microcapsules was low but increased dramatically in the presence of 0.2mol/L glucose. The prepared PAAC-grafted and GOD-immobilized microcapsules showed a reversible glucose-sensitive release characteristic. The proposed microcapsules provide a new mode for injection-type self-regulated drug delivery systems having the capability of adapting the release rate of drugs such as insulin in response to changes in glucose concentration, which is highly attractive for diabetes therapy.     

St-DVB凝胶化反应动力学机理的模型理论研究

高分子凝胶化反应对功能高分子骨架结构有重要影响，它经历溶胶一凝胶的不可逆转变（sol－geltransition）；导致高分子网络结构及分子尺寸的突变，动力学过程和机理十分复杂，因此，人们对这一领域的研究始终贯注了巨大兴趣．追溯过去，人们对高分子凝胶化过程的研究经历了由未考虑环化、搭环的Flory－stockmayer理论问；静态渗流理论［’］到动态凝胶化模型＊三个发展阶段·后者除克报了前两种的不足外，还引入了与几何形状密切相关的动态标度处理方法．近年来，分形概念的产生更激励了动态标度的发展，这种增长模型的研究方法考虑了增长…     

Total Synthesis of Phakellistatin 13 by Solution Method

Since George R. Pettit’s group isolated cycloheptapeptide phakellistatin 1 from sponge1, over ten similar cyclic peptides have been obtained2-5. Phakellistatin 134 (Figure 1) is a cycloheptapeptide isolated from the brown snubby sponge from the South Chi…     

Synthesis of Snake-cage Resins and Study of Their Separation Ability

IntroductionSnake-cageresin,alsoca1ledsnake-cagepolyelectrolyte['],isaspecialkindofamphotericresin.ItwasfirstinvestigatedbyHatchM.J.etal.in1957[z].Thetypicalandusefulsnake-cageresinisRetardation11A-8(l1A-8inthecon-text)manufacturedbyDowChemicalCoI,TD.Itissynthesizedbypolymerizingacrylicacidinsidethenetworkofastrongbasicanionexchangeresinwith8%crosslinking.Thus,theresinconsistsofacrosslinkedpolymermatrix,cage,andalinearpolymer,socalledsnake,whichisphysicallytrappedinsidethecage.Thecagepol…     

3-碘-苯并吡喃-4-酮与硫脲类反应的研究

3-碘-苯并吡喃-4-酮(1)与硫脲发生Micheal加成反应, 合成三个2-硫代-5-(2-羟基苯甲酰基)咪唑衍生物和五个2-亚氨基-5-(2-羟基苯甲酰基)噻唑衍生物。这些化合物结构经核磁共振光谱、红外光谱和元素分析均予以证实。