2,4-二羟基二苯甲酮合镍(Ⅱ)配合物的合成及热分解动力学研究

合成了一种新的镍(Ⅱ)配合物Ni(C13H9O3)2.2H2O,并用元素分析I、R、UV和摩尔电导分析等手段对配合物进行了表征,用热重-差热法(TG-DTG)研究了配合物的热分解动力学,得到第二步的动力学方程。结果表明,配体中羰基氧、邻位羟基氧与金属离子配位,金属离子与配体的化学计量比为1∶2。配合物在动态空气气氛中第二步热分解由机理函数f(α)=1-α控制,反应速率方程为:dα/dt=5.295×109[exp(-105.61×103)/RT]×(1-α)。

溴化轻稀土甘氨酸配合物的热分解动力学

用差示扫描量热法研究了溴化轻稀土甘氨酸配合物的非等温热分解过程,用Ozawa法、Kissinger法、Achar微分法及CoatsRedfern积分法计算了配合物的热分解动力学参数(E和A),并推断出了配合物失第1分子水、失第2分子水、脱甘氨酸步热分解反应函数,其热分解动力学方程分别为:dα/dt=A/β·e-E/RT(1-α),dα/dt=A/β·e-E/RT(1-α)2和dα/dt=A/β·e-E/RT(1-α)2。

热分解法制备纳米NdFeO_3气敏材料的研究

以分析纯的K3[Fe(CN)6]和NdCl3为原料,利用室温固相反应法制备纳米NdFeO3的前驱体Nd[Fe(CN)6],通过热分解前驱体得到气敏材料NdFeO3.用TG-DSC,XRD,TEM对产物进行了表征,并对其气敏性能进行了初步研究.结果表明:热分解法与溶胶-凝胶法相比可降低复合氧化物的生成温度及煅烧时间,形成的钙钛矿型NdFeO3粉体呈现圆柱状晶形,直径约为30 nm,长度为40 nm^50 nm.用热分解法制得的NdFeO3气敏元件呈现P型半导体特性,对H2S气体具有一定的灵敏度.

纳米SmFeO_3的合成及其H2S敏感特性研究

以无机物K3[Fe(CN)6]和Sm2O3为原料,用热分解配合物前驱体法制备了复合氧化物SmFeO3纳米粉体.用X-射线粉末衍射仪(XRD)和透射电镜(TEM)对产物的物相、形貌进行了表征.结果显示:热分解法在煅烧温度为600℃即可生成纳米晶SmFeO3,TEM显示产物为均匀的椭球形颗粒,充分表明该方法制备的材料具有良好分散性,且纯度较高.将合成材料制备成旁热式气敏元件,气敏性能测试结果表明:合成材料对H2S具有高的灵敏度和选择性,在最佳工作电压4V时对50μL/LH2S气体的灵敏度可达21.3倍,相对干扰气体C2H5OH来讲其选择性系数为4.44倍,而且响应很快,约2s,但恢复稍慢,40s左右.

纳米LaFeO_3的制备及H_2S气敏性能研究

以无机物K3[Fe(CN)6]和La(NO3)3.nH2O为原料,用热分解配合物前驱体法制备了LaFeO3纳米粉体.用X-射线粉末衍射仪(XRD)和透射电镜(TEM)对产物的物相、形貌进行了表征.本工作还以沉淀法相同温度条件下煅烧出的LaFeO3作了对比.结果显示:热分解法在煅烧温度为700℃即可生成纳米晶LaFeO3,TEM显示产物为均匀的椭球形颗粒,充分表明该方法制备的材料具有良好分散性,且纯度较高.将合成材料制备成旁热式气敏元件,气敏性能测试结果表明:合成材料对H2S具有高的灵敏度和选择性,在192℃工作时,对35μL/LH2S气体的灵敏度可达72倍.

MCr_2O_4(M=Co,Zn)纳米晶的合成及磁性

通过配合物热分解法制备MCr2O4(M=Co,Zn)纳米晶,并对其物相、表面微结构和磁性进行表征。结果表明,产物为直径40 nm左右的球形粒子,具有立方晶系尖晶石结构。磁滞回线表明,CoCr2O4在低温下表现出明显的亚铁磁性和较强的交换偏置场,矫顽力和交换偏置场分别为Hc=6.05×105A/m和He=1.93×104A/m,饱和磁化强度Ms和剩余磁化强度Mr分别为19.86和12.63 A.m2/kg,这可用CoCr2O4纳米晶的表面结构缺陷导致表面原子的磁结构自旋无序来解释。

Crystal structures and thermal decomposition kinetics of lanthanide complexes with 3,4,5-trimethoxybenzoic acid and 1,10-phenanthroline

A series of lanthanide complexes with the 3,4,5-trimethoxybenzoic acid （3,4,5-tmoba） and 1,10-phenanthroline（phen）, [Ln（3,4,5-tmoba）3phen]2（Ln = Pr（l）, Nd （2） and Ho（3））, have been synthesized and characterized by a series of techniques including elemental analysis, IR spectra, X-ray crystallography and TG/DSC-FTIR technology. The three complexes have two kinds of coordination modes, in which the Pr3＋ and Nd3＋ cations are nine-coordinated and the Ho3＋ cation is eight-coordinated. The three-dimensional IR accumulation spectra of gaseous products for complexes 1-3 were analyzed and the gaseous products were identified by the typical IR spectra obtained from the 3D surface graphs. Meanwhile, we obtained the activation energy E of the first steps of complexes 1-3 by the integral isoconversional non-linear （NL-INT） method and discussed the non-isothermal kinetics of complexes 1-3 using the Malek method. Finally, SB（m, n） was defined as the kinetic method of the first-step thermal decomposition. The thermodynamic parameters △G≠, △H≠ and △S≠ of activation at the peak temperature were also calculated.

Cobalt(Ⅱ) coordination polymers built on isomeric dipyridyl triazole ligands with pyromellitic acid:Synthesis,characterization and their effects on the thermal decomposition of ammonium perchlorate

Three new cobalt（II） coordination compounds, [Co（3,3＇-Hbpt）2（H2pm）（H20）2]＇2H20 （1）, [Co（4,4＇-Hbpt）（pm）0.5（H20）]＇3H20 （2） and [Co（3,4＇-Hbpt）（pm）0.5（H20）3]＇2H20 （3） （3,3＇-Hbpt = 3,5-bis（3-pyridyl）-lH-1,2,4-triazole; 4,4＇-bpt = 3,5-bis（4-pyridyl）- 1H-1,2,4-triazole, 3,4＇-Hbpt = 3-（3-pyridyl）-5-（4＇-pyridyl）-lH-1,2,4-triazole and Hapm = pyromellitic acid） have been synthe- sized by hydrothermal reactions. Single-crystal X-ray diffraction reveals that compound 1 has a one-dimensional （1D） chain network, 2 exhibits a four-connected three-dimensional （3D） structure with 1D open channels encapsulated by water molecules, while 3 displays a regular two-dimensional （2D） architecture connected through 1D metal helical chains. In addition, the effi- cacy of compounds 1-3 as additives to promote the thermal decomposition of ammonium perchlorate （AP） is explored by dif- ferential scanning calorimetry （DSC）.

Crystal structures and thermal decomposition mechanism of four lanthanide complexes with halogen-benzoic acid and 1,10-phenanthroline

This paper describes syntheses and structure determination of four lanthanide complexes [Nd(2-Cl-4-FBA) 3 phen] 2 (1, 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate, phen = 1,10-phenanthroline), [Ln(2,5-DClBA) 3 phen] 2 (Ln = Sm(2) and Tb(3), 2,5-DClBA = 2,5-dichlorobenzoate) and [Sm(2-Cl-4,5-DFBA) 3 (phen)(H 2 O)] 2 (4, (2-Cl-4,5-DFBA = 2-chloro-4,5-difluorobenzo- ate). The complexes were characterized by elemental analysis, infrared and ultraviolet spectra, and X-ray single-crystal diffraction. In the molecular structures of 1 4, two Ln 3+ ions are linked by four carboxyl groups, with two of them in a bridging bidentate mode and the other two in a bridging-chelating tridentate mode, forming four binuclear molecules. In addition, each Ln 3+ ion is also chelated to one phen molecule and one carboxyl group in the complexes, except each Sm 3+ ion in 4 which is bonded to one carboxyl group by unidentate mode and one H 2 O molecule. There are two different coordination polyhedrons for each Nd 3+ ion in the two similar molecular structures of 1 and they are a distorted monocapped square antiprismatic and a distorted tricapped triangular prism conformation, respectively. The coordination polyhedron for each Ln 3+ ion in 2 4 is a nine-coordinated distorted mono-capped square antiprismatic conformation. The complex 3 exhibits green luminescence under the radiation of UV light. The thermal decomposition behaviors of the complexes have been discussed by simultaneous TG/DSC-FTIR technique. The 3D surface graphs for the FTIR spectra of the evolved gases were recorded and the gaseous products were identified by the typical IR spectra obtained at different temperatures from the 3D surface graphs. Meanwhile, we discussed the nonisothermal kinetics of 1 4 by the integral isoconversional non-linear (NL-INT) method.