亚甲基[6,6]-富勒(fullerene)[60]单羧酸的合成研究

亚甲基[6,6]-fullerene[60]单羧酸是一个具有化学反应活性的fullerene[60]衍生物,可以作它合成得到一些新的具有潜在生化应用价值的水溶性fullerene[60]衍生物。本文详细报道了常规量合成亚甲基[6,6]-fullerene[60]单羧酸的技术。     

瓜环和金属改性的硫化镉光催化性质

以硫代乙酰胺为硫源,氯化镉为镉源,超声法制备银、钴离子掺杂的六元瓜环-硫化镉复合物。采用X射线粉末衍射、傅里叶变换红外光谱和扫描电子显微镜对催化剂结构和形貌进行表征,并进行催化降解染料的测试,考察Q[6]和金属离子对催化剂催化性能的影响。结果表明:采用瓜环复合和适量金属掺杂能使硫化镉可见光催化降解亚甲基蓝的性能显著提高约20%,且以瓜环对硫化镉协同增效作用为主。     

具有双稳态的化学反应中的涨落现象

化学反应中的非线性动力学行为一直受到人们的普遍的关注[1-3]Schlogl等人[4,5]曾用两个自催化反应模式说明连续的二级相变和不连续的一级相变特征．而在文献[6，7]中，我们提出在具有双稳态的化学反应中，存在类一级与类二级相变之间的转变点，而此转变点也具有类似Landau二级     

巴比妥酸与芳香醛的固相反应研究

固相有机化学反应作为绿色化学的重要组成部分是近年来发展起来的新领域 [1,2 ] .固相有机化学反应中 ,反应物分子受晶格的控制 ,运动状态受到很大限制 ,因此表现出比溶液更高的反应效率及反应选择性[3～ 6] .巴比妥酸具有生理活性 ,且有较高的化学反应活性 ,尤其是 C5位的氢 ,由于受相邻两个羰基的吸电子作用而具有较强的酸性 ( p H=4.0 0 ) .因此 ,巴比妥酸与芳香醛易发生 Knoevenagel型缩合反应 ,生成 C5取代的衍生物 - 5 -亚烃基巴比妥酸 .这类缩合反应在溶液中很容易发生 [7,8] ,近年来又发现在蒙脱土 KSF存在下 [9] 及无载体条件下…     

聚苯胺对抗坏血酸的电催化氧化及磁效应

磁场对生物体系及其中物理现象和化学反应的影响历来是人们关注的焦点[1]．磁场能影响分子、细胞、组织、器官乃至整个生物体系的新陈代谢功能．磁场对化学反应的影响通常是通过对自由基（对）施加作用而体现的，磁场改变了未成对电子的自旋方式，从而改变了反应的墙，进而改变化学反应的速率[2]．此外，磁场对电化学体系的影响也有报导[3]，外加磁场激发溶液流动，产生磁流体动力学效应（MHD）[4]，增大传质速度，影响电化学进程．本文研究聚苯胺（PAN）修饰电极上抗坏血酸（AA）的电催化氧化，并讨论了膜厚、溶液pH值、AA浓度（CAA…     

利用室温固态反应制备球霰石型CaCO3粒子

合成形态、大小及结构可人为调控的无机材料是现代材料科学的重要研究方向[1]. 借助于各类有机添加剂及模板剂的调控作用, 可利用溶液合成方法制备出形貌与结构受到有效调控的无机粒子[2,3]. 室温固态化学反应已被成功地应用于多种无机纳米粒子[4]及纳米线[5]的合成, 并显示出高效、节能、无污染和操作简便等优点, 因而在材料合成领域具有应用前景[6].     

N4-calix[6]arene及其铜锌配合物的合成与电喷雾质谱表征

酶的高选择性和高效催化作用使生命体能在温和条件下进行化学反应.研究发现[1]酶的活性部位具有特定的结构,可以通过体积识别、氢键、配位键等非共价相互作用对底物进行选择性识别.     

氯化铅纳米线的胶束模板诱导合成及其机理研究

一维纳米材料由于在光学、磁学、微电子学等领域中具有广阔的应用前景而引起了科技工作者的广泛兴趣 .目前 ,研究得最多的一维纳米材料为碳纳米管 [1,2 ] ,它的某些性质已得到实际应用 .而纳米线 (纳米丝、纳米纤维 )的研究尚处于初始阶段 ,至今已合成或制备出的纳米线只有硫化钼、硫化镉、氮化镓、砷化铟、硫酸钙、碳酸钡、碳化硼、锡 -铅、金、银、铋等十余种 [3～ 16 ] ,尚未见有氯化铅纳米线的报道 .氯化铅晶体通常呈九配位三帽三方柱层状结构 ,具有方向上的电性差异 .当进入纳米尺寸时 ,可能产生奇异的理化现象 .本文用反相胶团或 W/ …     

光敏CdS粉的制备与性能研究

硫化镉(CdS)是重要的半导体材料,尤其在可见光范围,已经应用到光电导、压电晶体和激光材料上^[1]。随着近代微电子技术的发展,CdS粉作为电子摄影中的感光材料,在复印机感光鼓及光敏电阻等领域已得到广泛的应用。它以工艺简单、易掺杂并且具有化学稳定性好的优点倍受重视。目前,国内CdS感光鼓用的基础材料CdS粉仍有相当数量依靠进口,而且价格昂贵,本课题组因此开展了这项研究工作。     

生物分子辅助水热法合成树枝状硫化镉

以CdCl₂·2.5H₂O和硫脲作先驱物,L-α-丙氨酸作为修饰剂,水热法合成了树枝状的硫化镉。采用XRD、SEM等表征手段对样品的相组成、形态、结构进行了考察。实验表明,反应时间,硫脲和L-α-丙氨酸对样品的形貌具有重要影响：随着时间的延长,硫化镉的形貌由花状逐渐变成树枝状,用硫代乙酰胺作为硫源或不加L-α-丙氨酸时均不能得到树枝状的硫化镉。荧光性质的研究表明,枝状硫化镉具有良好的荧光发光特性,探讨了枝状硫化镉可能的形成机制。     

S/Cd物质的量比对微波水热制备CdS微晶的形貌影响及光学性能研究

采用微波水热法,以CdCl2·H2O和Na2S2O3·5H2O为镉源和硫源,在不同的S/Cd物质的量比条件下合成了CdS微晶。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、场发射扫描电子显微镜(FE-SEM)、EDS、透射电子显微镜(TEM)等对样品的物相、形貌和元素组分进行了分析。结果表明:随着S/Cd物质的量比的增大,产物CdS的形貌发生规律性变化,由四面体结构逐渐转变为准球形结构;准球形结构具有分级结构,是由更小的纳米晶组装而成;光致发光性质研究结果表明,所得的CdS微晶具有较好的蓝光发射性能。     

Synthesis,characterization and stability of multicore-shell CdS-SiO<Subscript>2</Subscript> nanoparticles

Multicore-shell CdS-Si0₂ nanoparticles were synthesized in AOT/heptane/H₂O reverse micelles at room temperature. CdS-SiO₂ nanoparticles were characterized by UV-vis spectroscopy, TEM, and SEM methods. The results show that multicore-shell composites were formed. Fluorescence properties of composites were also investigated; the data imply that fluorescence properties of the silica-coated CdS nanoparticles were significantly improved when compared to those of the non-coated CdS nanoparticles. The stability of multicore-shell CdS-SiO₂ nanoparticles upon the UV irradiation was higher than that of non-coated CdS nanoparticles.     

Molten-salt Synthesis and Properties of ZnS with Hexagonal Prism Morphology

ZnS with hexagonal prism morphology has been synthesized successfully by molten-salt method with ZnS nanoparticles as precursors, and the ZnS nanoparticles were prepared by one-step solid-state reaction of Zn（CH3COO）2·2H2O with Na2S·9H2O at ambient temperature. Crystal structure and morphology of the product were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and HRTEM. Ultraviolet-visible optical absorption spectrum of the ZnS hexagonal prism shows a distinct red shift from that of bulk ZnS crystals and photoluminescence spectrum exhibits strong emissions at 380 and 500 nm, respectively. Further experiments were designed and the formation mechanism of the ZnS hexagonal prism has been also discussed in brief.     

Synthesis and Characterization of CdS Nanoparticles via Cyclic Microwave from Cadmium Oxalate

The present study reports synthesis and characterization of CdS nanoparticles prepared by cyclic microwave route with the use of [Cd(C₂O₄)·3H₂O] powder as a precursor. The products, with an average size ~15 nm, were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis, thermogravimetric analysis, transmission electron microscopy and Fourier transform infrared spectroscopy. Optical property of obtained product was investigated by photoluminescence spectroscopy. The prepared nanostructures displayed a very strong luminescence at 528 nm (2.34 eV) at room temperature.     

Co-Crystallization in systems with carnallite-type double salts

The RbCl · MgCl₂ · 6H₂O? NH₄Cl · MgCl₂ · 6H₂O? H₂O and CsCl · MgCl₂ · 6H₂O? NH₄Cl · MgCl₂ · 6H₂O? H₂O systems have been investigated at 50°C. The formation of continuous series of mixed crystals is observed. An almost complete coincidence of the distribution coefficients values of the components between the solid and liquid phases determined experimentally and calculated theoretically using only solubility data for the two double salts has been established. The 2 RbCl · CoCl₂ · 2H₂O? RbCl · MgCl₂ · 6H₂O? H₂O system has been studied at 25°C. It has been established that this system belongs to the simple eutonic type. The two double salts form no mixed crystals between each other. This fact is explained by the different character of the metal-ligand interaction of Mg²⁺ and Co²⁺ ions in aqueous halide systems.     

Synthesis and anticancer property of one Ce(III) compound based on 5-(2-pyrazinyl)tetrazole-2-acetic acid

Mononuclear [Ce(pztza)₂(H₂O)₆](pztza)·H₂O (1) (pztza = 5-(2-pyrazinyl)tetrazole-2-acetato) has been prepared and characterized by IR, elemental analysis and single-crystal X-ray diffraction. PEG_-5000 (poly(ethyleneglycol_-5000)) coated [Ce(pztza)₂(H₂O)₆](pztza)·H₂O nanoparticles (NPs) can disperse into distilled water. In vitro study on Hela cells shows that Hpztza is nontoxic while [Ce(pztza)₂(H₂O)₆](pztza)·H₂O NPs show high toxicity with half-maximal inhibitory concentration (IC₅₀) of 17 μg/mL (1.93 × 10^?5 M). In addition, such NPs can inhibit the migration of Hela cells effectively.     

Stability and optical properties of dispersions of CdS,ZnS, and Ag<Subscript>2</Subscript>S nanoparticles synthesized in microemulsion

CdS, ZnS, and Ag₂S nanoparticles have been synthesized in microemulsion. The synthesis of nanoparticles depend on the composition of the reaction medium and on the proportions of the precursors. The phase diagram for sedimentation stable dispersion of the nanoparticles synthesized in microemulsion has been determined. The region of the stable nanoparticle dispersion is much smaller than the region of the inverse microemulsion in the n-heptane-AOT-H₂O system. The UV-vis absorption and photoluminescence spectra of the CdS, ZnS, and Ag₂S nanoparticles have been investigated. The size of the nanoparticles increases with an increase in droplet size in the microemulsion, and this shifts the exciton peaks.     

Ab initio study of the structure,cooperativity, and vibrational properties in the mixed hydrogen‐bonded trimers of hydrogen isocyanide and water

The five trimers of H₂O···HNC···H₂O, H₂O···H₂O···HNC, HNC···H₂O···H₂O, H₂O···HNC···HNC, and HNC···HNC···H₂O have been studied with quantum chemical calculations. Their structures, harmonic vibrational frequencies and interaction energies have been calculated at the B3LYP and MP2 levels with the aug‐cc‐pVDZ and aug‐cc‐pVTZ basis sets. The cooperative effect on these properties has also been studied quantitatively. For HNC:(H₂O)₂ systems, the cyclic H₂O···H₂O···HNC trimer is most stable with an interaction energy of ?16.01 kcal/mol and a large cooperative energy of ?3.25 kcal/mol at the MP2/aug‐cc‐pVTZ level. For H₂O:(HNC)₂ systems, the interaction energy and cooperative energy in the H₂O···HNC···HNC trimer are larger than those in the HNC···HNC···H₂O trimer. The NH stretch frequency has a blue shift for the terminal HNC molecule in the HNC···H₂O···H₂O and HNC···HNC···H₂O trimers and a red shift in other cases. A many‐body analysis has also been performed to understand the interaction energies in these hydrogen‐bonded clusters. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Effect of the guest solvent molecules on preparation of different morphologies of ZnO nanomaterials from the [Zn2(1,4-bdc)2(dabco)] metal-organic framework

The host and the apohost framework of [Zn₂(1,4-bdc)₂(dabco)]?·?4DMF?·?½H₂O (1?·?4DMF?·?½H₂O) (1,4-bdc?=?1,4-benzenedicarboxylate and dabco?=?1,4-diazabicyclo[2.2.2]octane) were used for the preparation of ZnO nanomaterials. With calcination of the host framework of 1?·?4DMF?·?½H₂O, ZnO nanoparticles could be fabricated. By the same process on fully desolvated framework of 1, ZnO microrods composed of ZnO nanoparticles were formed. These results indicate with removal of the guest solvent from the pores of this metal-organic framework (MOF), nanoparticle agglomeration increases and the role of this MOF in preparation of ZnO nanoparticles was reduced.     

Novel Approaches to Metallization of Cellulose by Reduction of Cellulose-Incorporated Copper and Nickel Ions

Summary: Copper and nickel nanoparticles were synthesized in the insoluble microcrystalline cellulose support by reduction of metal ions with several reducers in various media resulting in cellulose-metal nanocomposites. Wide-angle X-ray scattering results showed that supramolecular structure of cellulose did not change. Crystalline Cu₂O and Cu⁰ nanoparticles were prepared with reducers NaBH₄ and N₂H₄ · H₂SO₄, CuO nanoparticles – with cellulose itself as a reducer. Crystalline Ni⁰ nanoparticles were synthesized with N₂H₄ · 2HCl and NaBH₄; Ni⁰ nanoparticles in amorphous form were prepared with KH₂PO₂ · H₂O. SEM revealed large agglomerates of metal particles on the fibre surface. ASAXS and TEM have shown the nanoparticles to be in the range 5–55 nm.