Preparation of SnO2 Nanoparticles from a New Tin(IV) Complex: Spectroscopic and Photoluminescence Studies

A new dimethyltin(IV) complex, {[Me₂Sn(O₂CNC₉H₆)]₂O}₂ (1), was prepared by reaction of dimethyltin(IV) dichloride with the quinoline-2-carboxylic acid and characterized by elemental analysis, IR, ¹H-, ¹³C-, ¹¹⁹Sn-NMR spectroscopes. The structure of 1 was determined by single-crystal X-ray diffraction. The results showed that 1 is a tetranuclear, centrosymmetric dimeric, and contains two endo-cyclic five-coordinated and two exo-cyclic six-coordinated tin atoms and a N-atom of the 2-quinaldic carboxylate ligand coordinated to exo-cyclic tin. Complex 1 was utilized as a precursor for SnO₂ nanoparticles by direct thermal decomposition at 500 °C in air. The nano-structure of SnO₂ was characterized by scanning electron microscopy and X-ray powder diffraction. The SnO₂ core showed a band gap of ~4 eV determined from the UV/visible absorption spectrum. The SnO₂ nanoparticles show stable photoluminescence (PL) with an emission centered at 557 nm.     

Sonochemical Synthesis of a New Lead(II) Coordination Polymer with 2-Quinoline Carboxylate Ligand: A Precursor for the Preparation of Nano-structured Lead(II) Oxide

Crystalline and nano-structure of a new Pb(II) coordination polymer, [Pb(NO₂)(2-quc)]_n (1), {Hquc?=?2-quinoline carboxylic acid} is synthesized via heat gradient and sonochemical methods, respectively. The newly synthesized structures are characterized by scanning electron microscopy (SEM), X- ray powder diffraction (XRD), IR and ¹HNMR spectroscopies, elemental analyses and single crystal X-ray diffraction is used to understand the exact structure of the crystalline 1. Thermal stability of nano and bulk samples of compound 1 are studied and compared through thermal gravimetric and differential thermal analyses. PbO nanoparticles are then produced by calcination of the nano-structure of compound 1 at 600?°C. The obtained PbO is characterized by XRD and SEM analyses.     

Hydrothermal Synthesis of Nanocrystalline Cerium(IV) Oxide Powders

Nanocrystalline cerium(IV) oxide (CeO₂) powders were prepared by heating solutions of cerium(IV) salts in the presence of urea under hydrothermal conditions at 120° to 180°C. The effects of the concentration of urea and hydrothermal treatment temperature on the morphology and crystallite size of the synthesized particles were investigated. The synthesized particles were angular, ultrafine CeO₂, with a cubic fluorite structure. Their crystallite size decreased from 20 to 10 nm with increasing urea concentration from 2 times to 8 times that of the Ce⁴⁺ ion. The size only slightly changed by calcining at temperatures below 600°C.     

新型多吡啶铂(Ⅱ)络合物的设计、合成及性能研究

由于特殊的分子构型及电子排布,具有平面四边形构型的多吡啶Pt(Ⅱ)络合物能够产生许多特殊的、具有潜在应用价值的激发态性质．本论文设计、合成了一系列以三联吡啶、6-苯基-2,2’-二联吡啶、菲啰啉为主配体,取代苯乙炔为辅助配体的多吡啶Pt(Ⅱ)络合物,系统地研究了它们的光物理性质,取得如下有意义的研究结果:     

Synthesis and Properties of Stannole-Containing Polymers by Reaction of Bis(cyclopentadienyl)titanacyclopentadiene-Containing Polymers and Tin(IV) Chloride

Polymers having bis(cyclopentadienyl)titanacyclopentadiene units in the main chain were prepared by the polymerization of a low-valent bis(cyclopentadienyl)-titanium(II) complex, generated in situ from bis(cyclopentadienyl)titanium dichloride (Cp₂TiCl₂) and n-butyllithium (2 equiv), with internal diynes such as 1,4-bis(1-hexynyl)-benzene and 4,4′-bis(1-hexynyl)biphenyl. The bis(cyclopentadienyl)titanacyclopentadiene-containing polymers were subjected to the reaction with tin(IV) chloride, followed by the treatment with methyllithium to give 1,1-dimethylstannole-containing organometallic polymers in moderate yields. The stannole containing polymers are soluble in organic solvents, whose number-average molecular weight was estimated to be 2,700–2,800 by GPC. Optical and electrochemical properties of the resulting stannole-containing polymers were studied by their UV-vis spectra and cyclic voltammetric analyses, from which they were supposed to have low LUMO energy levels.     

Electrochemical Synthesis and Sintering of Nanocrystalline Cerium(IV) Oxide Powders

Nanocrystalline CeO₂ powders were prepared electrochemically by the cathodic electrogeneration of base, and their sintering behavior was investigated. X-ray diffraction and transmission electron microscopy revealed that the as-prepared powders were crystalline cerium(IV) oxide with the cubic fluorite structure. The lattice parameter of the electrogenerated material was 0.5419 nm. The powders consisted of nonaggregated, faceted particles. The average crystallite size was a function of the solution temperature. It increased from 10 nm at 29°C to 14 nm at 80°C. Consolidated powders were sintered in air at both a constant heating rate of 10°C/min and under isothermal conditions. The temperature at which sintering started (750°C) for nanocrystalline CeO₂ powders was only about 100°C lower than that of coarser-grained powders (850°C). However, the sintering rate was enhanced. The temperature at which shrinkage stopped was 200°-300°C lower with the nanoscale powder than with micrometer-sized powders. A sintered specimen with 99.8% of theoretical density and a grain size of about 350 nm was obtained by sintering at 1300°C for 2 h.     

Salen异核双金属配合物的合成及催化性能研究

以水杨醛和乙二胺为原料,冰乙酸为催化剂,室温下在乙醇中反应得到双水杨醛缩乙二胺(salen)配体,接着与Co(II)、Ni(II)、Cu(II)和Zn(II)在乙醇中加热回流反应,得到salen单金属配合物,最后在室温下分别与Hg(II)在甲醇-氯仿溶剂体系中反应得到salen异核双金属配合物[M(salen)HgCl...     

Oxo-Titanium(IV) Complex/Polymer Composites—Synthesis,Spectroscopic Characterization and Antimicrobial Activity Test

The emergence of a large number of bacterial strains resistant to many drugs or disinfectants currently used contributed to the search of new, more effective antimicrobial agents. In the presented paper, we assessed the microbiocidal activity of tri- and tetranuclear oxo-titanium(IV) complexes (TOCs), which were dispersed in the poly(methyl methacrylate) (PMMA) matrix. The TOCs were synthesized in reaction to Ti(OR)₄ (R = ⁱPr, ⁱBu) and HO₂CR’ (R’ = 4-PhNH₂ and 4-PhOH) in a 4:1 molar ratio at room temperature and in Ar atmosphere. The structure of isolated oxo-complexes was confirmed by IR and Raman spectroscopy and mass spectrometry. The antimicrobial activity of the produced composites (PMMA + TOCs) was estimated against Gram-positive (Staphylococcus aureus ATCC 6538 and S. aureus ATCC 25923) and Gram-negative (Escherichia coli ATCC 8739 and E. coli ATCC 25922) bacteria and yeasts of Candida albicans ATCC 10231. All produced composites showed biocidal activity against the bacteria. Composites containing {Ti₄O₂} cores and the {Ti₃O} core stabilized by the 4-hydroxybenzoic ligand showed also high activity against yeasts. The results of investigations carried out suggest that produced (PMMA + TOCs) composites, due to their microbiocidal activity, could find an application in the elimination of microbial contaminations in various fields of our lives.     

Synthesis and Mechanical Properties of Chlorinated Polyvinyl Chloride (CPVC) Carboxylate Ionomer

In the present work, the preparation of CPVC carboxylate ionomer is explored. First, a graft copolymer, composed of polyacrylic acid as branched chains and chlorinated polyvinyl chloride as backbone, was synthesized by in-situ chlorinating graft copolymerization. Second, the acid groups of the graft copolymer were neutralized by sodium hydroxide in order to prepare the ionomer. The ionomer was determined by Fourier transform infrared absorption spectrometry, differential scanning calorimetry, dynamic mechanical analysis, and mechanical properties. The results showed that the ionomer was synthesized successfully and its mechanical properties were enhanced notably compared with the graft copolymer.     

Synthesis and Characterization of New Ethylenediamine Platinum(IV) Complexes Containing Lipophilic Carboxylate Ligands

A series of new ethylenediamine (en) platinum(IV) complexes of the type Pt((IV))enX(2)A(2), with X(2) = cyclobutane-1,1-dicarboxylato (CBDCA), dichloro or bis(decanoato) and A = acetato, dodecanoato, tetradecanoato, hexadecanoato, octadecanoato, adamantanecarboxylato (Ad) or 3alpha, 12alpha-diformoxy-5beta-cholato (DFCA) were synthesized and characterized by elemental analysis, infrared and NMR ((1)H and (13)C) spectroscopic techniques. Previous platinum(IV) compounds were usually restricted to trans-dihydroxo or trans-dichloro platinum(IV) complexes. Recently trans-dicarboxylato platinum(IV) complexes with mainly acetate, trifluoracetate or short-chain carboxylate groups (<11 carbons) in the axial position have been described in the literature([1,2,3]). In this paper we report on the synthesis and characterization of a new class of ethylenediamine platinum(IV) compounds that have high lipophilic long-chain carboxylate ligands either in the axial or equatorial position. The platinum(IV) compounds with the lipophilic trans-carboxylate ligands in the axial position were prepared by acylation of the trans-dihydroxo platinum(IV) species using an acyl halide in the presence of pyridine. In contrast to previous publications([1]) the yields were excellent (up to 94%!).     

脲基苯乙炔4-′(对甲基苯基)-6-苯基-2,2′-二联吡啶铂(II)络合物的合成

本文通过异氰酸酰化反应合成了含有脲基的苯乙炔新型配体及以它作为辅助配体的4′-(对甲基苯基)-6-苯基-2,2′-二联吡啶铂(II)络合物,初步研究了铂(II)络合物的光物理性质,发现由于脲基的存在,当浓度大于3.32×10-5mol/L时铂(II)络合物能够发生分子间簇集.     

树枝形聚合物修饰双8-羟基喹啉衍生物的合成及稳态光物理性质研究

设计合成了1—3代芳醚骨架树枝形聚合物修饰的双8-羟基喹啉衍生物．对这些化合物在不同溶剂中的荧光光谱研究表明，随着代数的增加，目标树枝形聚合物的荧光量子产率增大，树枝形聚合物对核心发色团具有一定的隔离作用，并且目标分子内可以发生从骨架向核心发色团的能量传递．     

Enhanced Properties of Tin(IV) Oxide Based Materials by Field-Activated Sintering

The densification of SnO₂ (0.9 mol)–Sb₂O₃ (0.1 mol) solid solution without any additives was studied by conventional and field-activated sintering technique (FAST). FAST sintering achieved a relative density value of 92.4% at 1163 K for 10 min versus 61.3% in conventional sintering at 1273 K for 3 h. An abnormal reduction of the IR transmittance and a semiconductor defect structure with only one donor level in the SnO₂ energy gap were noticed in the FAST-sintered as compared with the conventionally sintered Sn_0.82Sb_0.18O₂ solid solution. A high charge carrier concentration (i.e., electronic conduction) was shown in the FAST-sintered sample by conductivity measurements and the negative values of the Seebeck coefficient.     

含有蒽酰亚胺的铜(I)配合物的合成、结构及光谱研究

合成了两个含蒽酰亚胺基团的新配体N-(2-(6-氨基吡啶))-9-蒽酰亚胺(L1)和N,N′-(2,6-吡啶基)-二(9-蒽酰亚胺)(L2),以及L1的铜(I)配合物[CuL1(PPh3)2](BF4)(1),并研究了它们的结构和光谱性质.理论计算表明配体L1配位前为反式构象,配合物1的晶体结构显示L1配位后发生结构扭曲呈顺式构象,羰基氧原子与铜(I)离子配位.光谱研究表明配体L1和配合物1都表现出蒽的特征吸收和发射峰.     

Effect of pH of Medium on Hydrothermal Synthesis of Nanocrystalline Cerium(IV) Oxide Powders

Well-crystallized cerium(IV) oxide (CeO₂) powders with nanosizes without agglomeration have been synthesized by a hydrothermal method in an acidic medium by using cerium hydroxide gel as a precursor. The relationship between the grain size, the morphology of the CeO₂ crystallites, and the reaction conditions such as temperature, time, and acidity of the medium was studied. The experiments showed that with increasing reaction temperature and time, the CeO₂ crystallites grew larger. The crystallites synthesized in an acidic hydrothermal medium were larger and had a more regular morphology than the ones synthesized in a neutral or alkaline medium when the reaction temperature and time were fixed. The CeO₂ crystallites synthesized in an acidic medium were monodispersed; however, there was vigorous agglomeration among the grains synthesized in a neutral or alkaline medium. It was demonstrated that the hydrothermal treatment was an Ostwald ripening process and the acidity (pH) of the used hydrothermal medium played a key role in the dissolution of smaller grains. It is proposed that the dissolution process can control the kinetics of the growth of larger grains.     

La2(MoO4)3:Eu3+纳米红色荧光粉的合成及发光特性

以硬脂酸镧和硬脂酸铕为反应物,采用溶剂热法合成了Eu3+离子掺杂的La2(MoO4)3:Eu3+纳米红色荧光粉。利用TEM、 XRD、FL对其形貌、结构和发光性能进行了表征。研究了溶剂种类、反应时间、反应温度、Eu3+掺杂浓度对产物微观形貌和发光性能的影响。结果表明：以异丙醇为溶剂,反应温度180℃、反应时间12h,得到的样品结晶度高、分散性好、形貌均一,粒径小于100nm。该样品可被近紫外光(391nm)和蓝光(462.5 nm)有效激发,最大发射波长位于613.5 nm,为窄带的红光。La2(MoO4)3:Eu3+的发光强度与Eu3 +离子掺杂浓度有关,其最佳掺杂浓度为15%（摩尔分数）。     

Synthesis, Crystal Structure, Spectroscopic and Thermal Properties of a Novel Complex of Hydantoin-5-acetic acid with Co(II)

The complex, tetraaqua bis(hydantoin-5-acetato) cobalt(II) was synthesized by the reaction of hydantoin-5-acetic acid and CoCl₂·6H₂O presence of NaHCO₃. The structure of the complex was determined by X-Ray single crystal data the thermal analyses, FT–IR and magnetic susceptibility data are also presented. The monoclinic crystal of the title compound, [Co(C₅H₅N₂O₄)₂(H₂O)₄], lie across centers of inversion in space group P21/c. The complex features a distorted octahedral [CoO₆] coordination with hydantoin-5-acetato and water ligands. The hydantoin-5-acetato anion is bonded to the cobalt(II) ion via its deprotonated carboxylic acid O atom. The complex molecules show three dimensional supramolecular networks by O–H···O and N–H···O interactions.     

N,N''''-双(2-氨乙基)邻苯二甲酰胺合Cu(Ⅱ)的合成与表征

合成了一种新型配体N,N'-双(2-氨乙基)邻苯二甲酰胺(L),并合成了它的Cu(Ⅱ)配合物.进行了核磁、元素分析、红外、荧光等表征实验.结果表明,配体可以与Cu(Ⅱ)形成配合物.     

Effect of Cobalt(II) Oxide and Manganese(IV) Oxide on Sintering of Tin(IV) Oxide

Additions of 0. 5 to 2. 0 mol% of CoO or MnO₂ onto SnO₂ promote densification of this oxide up to 99% of theoretical density. The temperature of the maximum shrinkage rate ( T_M ) and the relative density in the maximum densification rate (p*) during constant sintering heating rate depend on the dopant concentration. Thus, dopant concentration controls the densifying and nondensifying mechanisms during sintering. The densification of SnO₂ witih addition of CoO or MnO₂ is explained in terms of the creation of oxygen vacancies.