导电高分子PEDOT/PSS稳定的Pt3Co纳米粒子的制备及电、磁性

利用一步共还原法在导电高分子聚二氧乙基噻吩/聚对苯乙烯磺酸(PEDOT/PSS)水溶液中合成了磁性纳米复合物Pt₃Co-PEDOT/PSS. 利用透射电镜(TEM)、X射线衍射(XRD)、拉曼光谱、超导量子干涉仪(SQUID)对其进行了表征.结果表明Pt₃Co纳米粒子为面心立方结构(fcc), 粒子平均粒径为9.6 nm, 标准偏差为2.4 nm. 用旋转涂膜法制备的Pt₃Co-PEDOT/PSS薄膜导电率()在1.6～4.0 S/cm之间. 当温度在阻塞温度(T_B, 110.5 K)以上时, 纳米复合物Pt₃Co-PEDOT/PSS显示出超顺磁性, 低于T_B时呈铁磁性, 在5 K时其剩磁(M_r)和矫玩力(H_c)分别为4.1 emu/g和701 Oe(奥斯特).     

二维Co(nip)2(py)2(H2O)2配合物的水热合成, 晶体结构和热分解机理研究(nip＝5-硝基间苯二甲酸根, py＝吡啶)

用水热法以5-硝基间苯二甲酸和吡啶为配体合成并培养了Co(nip)₂(py)₂(H₂O)₂的单晶. 对单晶进行了X射线单晶衍射分析、元素分析、傅里叶变换红外光谱分析、差热分析和热重-微商热重分析. 该配合物晶体为单斜晶系, 属于P2(1)/c空间群. 晶胞参数为a＝1.1662(3) nm, b＝1.7734(4) nm, c＝0.6988(2) nm, β＝102.46(4)°, V＝1.4112(6) nm³, Z＝2, D_c＝1.585 Mg/m³, μ(Mo Kα)＝0.688 mm^－1. 所有晶体数据的R因子为: R₁＝0.1064, wR₂＝0.1270; 最终R因子[I＞2σ(I)]为: R₁＝0.0467, wR₂＝0.1008. X射线单晶衍射分析的结果表明, 依靠分子内氢键、分子间氢键、硝基氧之间的弱相互作用以及π-π堆积作用, 配合物分子被连成二维无限平面结构. 根据配合物的热分析结果, 配合物及热分析各阶段残渣的傅里叶变换红外光谱, 我们推测出了配合物的热分解机理.     

L-天冬氨酸与阴离子表面活性剂SDS的相互作用

用电导法、表面张力法和荧光探针法测定了L-天冬氨酸(L-Asp)对十二烷基硫酸钠(SDS)胶束聚集性能的影响以及L-Asp在SDS胶束中的定位, 用循环伏安法研究了SDS/H₂O体系中L-Asp的电化学特性. 结果表明, L-Asp的加入能使SDS的临界胶束浓度cmc减小、胶束的聚集数增加. SDS表面胶束和SDS/n-C₄H₉OH/表面混合胶束均对L-Asp电化学氧化具有一定的催化作用.     

一个新颖的三维异核锑(III)-镨(III)配合物[Sb2-μ4-(EDTA)2Pr(H2O)5]NO3•4H2O的合成、晶体结构及热分解研究

合成了锑-镨与乙二胺四乙酸形成的新颖三维配合物[Sb₂-μ₄-(EDTA)₂Pr(H₂O)₅]NO₃•4H₂O, 用元素分析、红外光谱、热分析及X射线单晶衍射法等进行了组成和结构表征. 结果表明该配合物属正交晶系, 空间群Pnn2; 晶胞参数: a＝1.07031(2) nm, b＝2.30805(4) nm, c＝0.72343(2) nm, V＝1.78711(7) nm³, Z＝2, D_c＝2.202 g/cm³, F(000)＝1164, μ＝2.955 mm^－1, GOF＝1.000, 最终偏离因子R₁＝0.0203, wR₂＝0.0545 [I＞2σ(I)]. 在标题化合物中, 每个镨(III)离子的配位数为9, 与五个水分子中的五个氧原子和四个羧基氧原子配位, 形成三帽三角棱柱空间配位多面体. 锑(III)与EDTA离子中的四个氧原子和两个氮原子配位, 在赤道平面上有一孤对电子. 同时讨论了配合物的热分解过程.     

稀土高氯酸盐-谷氨酸配合物[Pr2(L-α-Glu)2(ClO4)(H2O)7](ClO4)3•4H2O的低温热容和热化学研究

合成了一种稀土高氯酸盐-谷氨酸配合物. 经TG/DTG、化学和元素分析、FTIR及与相关文献对比, 确定其组成为[Pr₂(L-α-Glu)₂(ClO₄)(H₂O)₇](ClO₄)₃•4H₂O, 纯度为99.0%以上. 利用显微熔点仪分析发现其没有熔点. 在78～370 K温区, 用精密绝热量热仪测量其低温热容, 在285～306 K温区发现一明显吸热峰, 归结为固-固相变过程. 通过相变温区三次重复热容测量, 得到相变温度T_tr、相变焓Δ_trH_m和相变熵Δ_trS_m分别为(297.158±0.280) K, (12.338±0.016) kJ•mol^－1和(41.520±0.156) J•K^－1•mol^－1. 用最小二乘法将非相变温区的热容对温度进行拟合, 得到了热容随温度变化的两个多项式方程. 用此方程进行数值积分, 得到每隔5 K的舒平热容值和相对于273.15 K的热力学函数值. 根据TG/DTG结果, 推测了该配合物的热分解机理. 依据Hess定律, 选择1 mol•dm^－3盐酸为量热溶剂, 利用等温环境溶解-反应量热计, 测定了该配合物的标准摩尔生成焓为: Δ_fH_m⁰＝－(7223.1±2.4) kJ•mol^－1.     

微孔[Me4N]2HgGe4S10的溶剂热合成与表征

用溶剂热方法合成了[Me₄N]₂HgGe₄S₁₀, 通过单晶X射线衍射, IR, DSC-TG手段对其进行了表征. 结果表明, 标题化合物属四方晶系, I-4空间群, 晶胞参数a＝0.92687(8) nm, c＝1.43739(12) nm, V＝1.23484(18) nm³, Z＝2, Mo Kα λ＝0.071073 nm, R₁＝0.0570, wR₂＝0.1374, 空旷骨架结构由超四面体Ge₄S₁₀与HgS₄四面体共用顶点连接而成, 有机模板离子在一维孔道中. 该化合物具有一定的热稳定性, 在320 ℃发生分解形成GeS₂.     

[Gd2(Gly)6(H2O)4](ClO4)6(H2O)5的合成、晶体结构与热化学研究

利用微波技术合成了配合物[Gd₂(Gly)₆(H₂O)₄](ClO₄)₆(H₂O)₅, 进行了化学成分分析、红外表征和热重分析. 应用X衍射仪测定其晶体结构, 该晶体为一维链结构, 属三斜晶系, P 空间群, 晶胞参数: a＝1.1569(17) nm, b＝1.4138(2) nm, c＝1.5642(2) nm, α＝96.910(2)°, β＝102.735(2)°, γ＝105.512(2)°, V＝2.3606(6) nm³, Z＝2, D_c＝2.144 g•cm^－3. 采用精密溶解-反应量热计, 通过设计热化学循环, 计算出了该配合物的标准摩尔生成焓为 －(7960.73±3.23) kJ•mol^－1.     

具有二重穿插结构的配位聚合物[Cu(bpy)(OH)]n的合成与结构表征

利用水热反应, 合成了一个具有二重穿插结构的一价铜配位聚合物[Cu(bpy)(OH)]_n (1) (bpy＝4,4'-联吡啶), 并利用元素分析, X射线单晶衍射, 红外光谱以及热重分析等手段对标题化合物进行了表征. 晶体学数据: 四方晶系, I41/acd空间群, a＝1.41802(6) nm, b＝1.41802(6) nm, c＝3.8568(3) nm, β＝90.00°, V＝7.7552(7) nm³, Z＝32, S＝1.074, 最终残差因子[I＞2σ(I)] R₁＝0.0345, wR₂＝0.0767, 对于全部数据R₁＝0.0566, wR₂＝0.0867.     

2,5-二乙氧甲酰氨基-1,3,4-噻二唑超分子化合物的合成和晶体结构

报道了一种用1,6-二取代二硫脲在DMF中加热回流直接脱H₂S关环合成2,5-二取代1,3,4-噻二唑类化合物的新方法, 并用此方法合成了2,5-二乙氧甲酰氨基-1,3,4-噻二唑. 用元素分析、核磁共振氢谱、红外光谱进行了表征, 用X射线单晶衍射法确定了其单晶结构. 晶体属单斜晶系, P2₁/c空间群, a＝1.0093(4) nm, b＝0.9035(4) nm, c＝1.2924(6) nm, β＝96.785(9)°, V＝1.1703(9) nm³, Z＝4, D_c＝1.477 g/cm³, F(000)＝544, μ＝0.287 mm^－1. 该化合物通过分子间氢键形成了一种二维网状结构的超分子, 由于分子间的作用力使其分子又沿c轴呈层状堆积.     

混合价四核锰配合物[Mn4O2(ClCH2COO)7(bipy)2]•H2O的合成、晶体结构及性质研究

在乙腈溶液中, 由混合价三核锰配合物[Mn₃O(ClCH₂COO)₆(py)₂]•(H₂O) (py为吡啶)与2,2′-联吡啶(bipy)反应合成了混合价(Mn₃^IIIMn^II)四核锰配合物[Mn₄O₂(ClCH₂COO)₇(bipy)₂]•H₂O. 采用元素分析、红外光谱、热分析和X射线单晶衍射法确定了其组成和结构. 标题化合物晶体属于三斜晶系, 空间群P-1, 晶胞参数: a＝0.89854(13) nm, b＝1.4027(2) nm, c＝1.9037(3) nm, α＝93.518(3)°, β＝96.736(3)°, γ＝94.875(3)°, V＝2.3680(6) nm³, Z＝2, D_c＝1.734 g/cm³, F(000)＝1238, GOF＝1.036, R₁＝0.0592, wR₂＝0.1162 [I＞2σ(I)]. 在标题化合物中, 配位结构单元中心为一蝶型[Mn₄(μ₃-O)₂]^7＋多核簇, 含有2个Mn₃(μ₃-O)单元, 具有近似C₂对称轴. 4个Mn离子均为六配位, 外围配体为7个氯乙酸根和2个2,2′-联吡啶, 处于变形的八面体环境. 变温磁化率研究表明标题化合物在整体上表现为反铁磁性耦合作用, 但在低温下的磁相互作用较为复杂.     

ZnAc2·2H2O在空气中的热分解动力学研究

用TG/DTA,DSC和XRD技术研究了固态物质ZnAc2.2H2O在空气中的热分解过程.结果表明,ZnAc2.2H2O在空气中发生两步分解,其失重率与理论计算失重率相符.XRD结果表明,ZnAc2.2H2O分解的最终产物为ZnO.用Friedman法和Flynn-Wall-Ozawa(FWO)法求得分解过程的活化能E,并通过多元线性回归方法给出了可能的机理函数.ZnAc2.2H2O在空气中两步分解的活化能分别为119.82和66.82kJ/mol.     

水杨酸钴非等温热分解动力学研究

用热分析(TG/DTG)、X射线衍射(XRD)技术研究了固态物质水杨酸钴在空气中热分解的过程。热分析结果表明,水杨酸钴在空气中分两步分解,其失重率与理论计算失重率相吻合;XRD结果表明,水杨酸钴分解的终产物为Co3O4。用Friedman法和Flynn-Wall-Ozawa(FWO)法求取了分解过程的活化能E,并用多元线性回归和多元非线性回归法给出了可能的机理函数,由这些方法得到的动力学数据相互比较吻合。     

非等温TG- DTG法确定2,2''- 联吡啶- 对甲氧基苯甲酸铕(Ⅲ)热分解反应的机理函数和动力学参数

采用TG-DTG和DTA技术研究了2,2'-联吡啶-对甲氧基苯甲酸铕(Ⅲ)在静态空气中的非等温热分解过程及动力学,根据TG曲线确定了热分解过程中的中间产物及最终产物,运用微分法与积分法对非等温动力学数据进行分析,推断出第一步的动力学方程为dα/dt=Aexp(-E/RT)2(1-α)1/2.     

CoC2O4·2H2O在空气中的热分解动力学研究

纳米Co3O4具有尖晶石结构,Co3 占据八面体位,具有较高的晶体场稳定化能,在空气中低于800℃时十分稳定,是优良的催化材料[1]。Co3O4还可以作为高比能锂离子电池负极材料具有非常好的电化学活性,充放电容量高达960m A h·g-1。纳米Co3O4在紫外、可见及近红外区域都有良好的吸收效果,因此,在隐身技术、保温节能技术等领域具有潜在的应用前景。所以,Co3O4超细粉体的制备和应用研究具有十分重要的意义。我们合成了草酸盐先驱物制备纳米Co3O4用作隐身材料,因此对先驱物的热分解过程研究是十分必要的。热分析方法在了解先驱物热分解反应的物理…     

Kinetics of thermal decomposition of nickel oxalate dihydrate in air

Thermal decomposition taking place in solid state complex, NiC₂O₄·2H₂O, has been investigated in air by means of TG–DTG/DTA, DSC, XRD. TG–DTG/DTA curves showed that the decomposition proceeds through two well-defined steps with DTA peaks closely corresponding to the weight loss obtained. XRD showed that the final decomposition product of NiC₂O₄·2H₂O was NiO. Kinetics analysis of NiC₂O₄·2H₂O decomposition steps was performed under non-isothermal conditions. The activation energies were calculated through Friedman and Flynn–Wall–Ozawa (FWO) methods, and the most possible kinetic model function has been estimated through the multiple-linear regression method. The activation energies for the two decomposition steps of NiC₂O₄·2H₂O were 171.1 ± 4.2 and 174.4 ± 8.1 kJ/mol, respectively.     

Study of The Mechanism and Kinetic Parameters of The Thermal Decomposition of Cobalt Sulphate Hexahydrate

Thermogravimetry (TG-DTG), and differential thermal analysis (DTA) were used in the study of the kinetics of decomposition of cobalt sulphate hexahydrate under an air atmosphere. The kinetics of the particular stages of CoSO₄ 6H₂ O decomposition were evaluated from the dynamic mass loss data. The values of the kinetic parameters for each stage of the thermal decomposition were calculated from the α(T) data by using the integral method, applying the Coats-Redfern approximation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparative studies of latex obtained of rubber tree clones (Hevea brasiliensis) - series iac 328 - votuporanga - sp

Membranes of latex extracted of the seringueira tree (Hevea brasiliensis), genetically improved by selection and statistics methods, were prepared by air drying a 10 mL suspension of the ammonia in latex 10% (v/v). TG-DTG and DSC curves were used to characterize the membranes. Thermal stability and thermal decomposition of these compounds were analyzed. The results obtained show no differences among latex from different clones. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Stability of Robust Unsymmetrical Copperporphyrins with Multiple Diphenylamino and Nitro Substituents

The syntheses and thermal stability properties of a series of amino and nitro substituted copperporphyrins are described. The thermal decomposition temperatures of the porphyrins were determined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The on-set thermal decomposition temperatures of the unsymmetrical porphyrins were found to be high in the range of 350 – 405 °C (DSC), 374 – 441 (TGA in air), 395 – 411 °C (TGA under nitrogen atmosphere), and 410 – 424 °C (DTA in air). Substituent dependent thermal stability trends were also studied. The trend is variable depending on the thermal analysis technique utilized. Possible reasons for such variation are discussed. These porphyrins are thermally robust even in the melamine-based sol-gel matrix. Containing 20% by weight of the substituted unsymmetrical copperporphyrin, melamine-based sol-gel showed no indication of decomposition until ?400 °C.     

Study on the decomposition kinetics of FOX-7 and HNF

At TNO Prins Maurits Laboratory the characterisation and application of energetic materials is one of the main research topics. In this respect, the activities are focussed on using thermal analysis techniques such as TG/DTA and DSC. Standard DSC and TG/DTA techniques usually apply a linear temperature increase. During this gradual temperature change, the sample may pass certain phase changes related to different crystal structures, followed by a melting/decomposition of the material. In this way physicochemical properties like phase change temperatures, melting point, enthalpy of melting, decomposition temperature, etc. can be determined. By applying different heating rates, an analysis of the decomposition kinetics can be performed as well, which gives additional information on the decomposition process of the material. In this way the activation energy of the decomposition process and the 'shelf-life' of the material, when stored at a certain temperature, can be assessed. In a co-operation with the Technical University of Aachen, two relatively new and promising energetic materials were investigated: FOX-7 and HNF. FOX-7, or 1,1-diamino-2,2-dinitroethylene, is a less sensitive explosive, which could find application as a substitute of RDX (less sensitive but with preservation of performance). Hydrazinium nitroformate (HNF) is an oxidiser with potential use as a high-performance, chlorine-free ingredient in rocket propellants. The results of the TG/DTA and DSC tests, as well as the results of the analysis of the decomposition kinetics of these two materials, will be reported and discussed in this paper. This revised version was published online in July 2006 with corrections to the Cover Date.     

An investigation on the solid state pyrolytic decomposition of bimetallic oxalate precursors of Ca, Sr and Ba with cobalt: A mechanistic approach

The mixed metal oxalate precursors, calcium(II)bis(oxalato)cobaltate(II)hydrate (COC), strontium(II)bis(oxalato)cobaltate(II)pentahydrate (SOC) and barium(II)bis(oxalato)cobaltate(II)octahydrate (BOC) have been synthesized and their thermal stability was investigated. The complexes were characterized by elemental analysis, IR spectral and X-ray powder diffraction studies. Thermal decomposition studies (TG, DTG and DTA) in air showed that the compound COC decomposed mainly to CaC₂O₄ and Co₃O₄ at 340 °C, and a mixture of CaCO₃ and Co₃O₄ identified at 510 °C. A mixture of CaCO₃ and Ca₃Co₂O₆ along with the oxides and carbides of both the cobalt and calcium were attributed at 1000 °C as end products. DSC study in nitrogen ascertained the formation of a mixture of CaO and CoO along with a trace of carbon at 550 °C. The mixture species, SrC₂O₄, CoC₂O₄ and Co₃O₄ were generated at 255 °C in case of SOC in air, which ultimately changed to CoSrO₃, SrCO₃ and oxides of strontium and cobalt at 1000 °C. The several mixture species also generated as intermediate at 332 and 532 °C. The DSC study in nitrogen indicated the formation of CoSrO_x (0.5 < x < 1) as end product. In case of BOC in air, a mixture of BaCoO₂, BaO, CoO and carbides are identified as end product at 1000 °C through the generation of several intermediate species at 350 and 530 °C. A mixture of BaO and CoO is identified as end product in DSC study in nitrogen. The kinetic parameters have been evaluated for all the dehydration and decomposition steps of all the three compounds using four non-mechanistic equations. Using seven mechanistic equations, the kind of dominance of kinetic control mechanism of the dehydration and decomposition steps are also inferred. The kinetic parameters, ΔH and ΔS of all the steps are explored from the DSC studies. Some of the decomposition products are identified by IR and X-ray powder diffraction studies.