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1.
Cis-dioxo-tungsten(Ⅵ) complex, (NH2CH2CH2NH2)[(NH2CH2CH2NH3)2WO2(NHC6H4NH)2]2·H2O is synthesized at room temperature by the reaction of sodium tungstate with o-phenylenediamine. The crystal structure of complex was determined by X-ray diffraction structural analysis. The results show that complex belongs to monoclinic system with space group P21/ c, a=0.712 8(2) nm, b=3.081 1(10) nm, c=0.981 9(3) nm, β=102.615(4)°, V=2.104 4(11) nm3, Z=2, μ=55.26 cm-1, F(000)=1 176. Compared the complex with its analogous biomimetic complexes of the cofactor of molybdoenzymes and tungstoenzymses, it is found that the variance of the coordination atoms and the metal ions center have no influence on the coordination feature, and exhibits distored octahedral coordination with cis-dioxo o-phenylenediamine. CCDC: 252834.  相似文献   

2.
通过室温固相反应制备了不同形貌的EuF3和SmF3纳米微粒,并利用XRD,TEM,SEM,和XPS对产物进行了表征。研究表明氟源对所得的稀土氟化物的尺寸与形貌有着重要的影响。通过硝酸盐与NH4F的反应得到了盘状的EuF3和SmF3微粒,而硝酸盐与HF·NH4F的反应得到的是不规则的EuF3和SmF3微粒。EuF3微粒的荧光光谱表明它们的发射峰的强度与尺寸与形貌有关。  相似文献   

3.
用溶胶凝胶法制备了复合固体电解质xNH4PO3-SiO2(x=1,2,4),并研究了该电解质在125~250 ℃范围内的导电性能。复合电解质的相结构分析表明,NH4PO3和SiO2在溶胶凝胶法制备过程中没有发生化学反应;复合电解质的电导率随着NH4PO3含量增大而提高,并与NH4PO  相似文献   

4.
主要考察了NO2对Cu/SAPO-34 分子筛催化剂在整个温度范围内(100-500 ℃)NH3选择性催化还原(SCR)NO性能的影响. 研究所使用样品为新鲜Cu/SAPO-34 催化剂在750 ℃下水热处理4 h 的稳定期样品.通过X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的结构以及形貌进行表征,采用SCR活性评价、动力学实验以及原位漫反射傅里叶变换红外光谱(in situ-DRIFTS)表征催化剂的性能以及催化剂表面物种的变化. 活性评价实验结果表明,NO2会抑制催化剂的低温(100-280 ℃)活性,但其存在会提高催化剂的高温(280 ℃以上)活性. 与此同时,随着反应物中NO/NO2的摩尔比例减少,由于NH4NO3物种的分解,副产物(N22O)的浓度增大. 动力学结果表明,Cu/SAPO-34 催化剂上快速SCR反应的表观活化能(Ea=64.02 kJ·mol-1)比标准SCR反应的表观活化能(Ea=48.00 kJ·mol-1)更大. In situ-DRIFTS实验结果表明NO比NO2更容易在催化剂表面形成硝酸盐,并且NO2更容易与吸附在Brønsted 酸性位上的NH3物种反应生成NH4NO3. 低温下,催化剂表面的NH4NO3物种会覆盖SCR反应的活性位,造成活性降低,但在高温时,形成的NH4NO3物种一部分会被NO还原为N2,而另一部分会直接热分解为N2O,造成催化剂的选择性降低.  相似文献   

5.
鲁晓明  宋富根  王波  李丽 《无机化学学报》2005,21(11):1687-1690
Cis-dioxo-catecholatotungsten(Ⅴ) complex (NH2CH2CH2NH3)4[WO2(OC6H4O)2]2(NH3CH2CH2NH3)·H2O (1) was synthesized at room temperature by the reaction of tetrabutyl ammonium decatungstate with catechol in the mixed solvent of CH3OH, CH3CN and NH2CH2CH2NH2. The crystal structure of complex was determined by X-ray diffraction structural analysis. The results show that complex belongs to monoclinic system with space group P21/c,a=0.712 8(3) nm, b=3.082 3(11) nm, c=0.982 8(4) nm, β=102.639(6)°, V=2.106 8(14) nm3, Z=2, R1=0.062 8, wR2=0.183 7. Compared the complex with its analogous complexes (NH2CH2CH2NH3)3[MoO2(OC6H4O)2], it is found that the coordination structure of W have no changes in the processing of electron transfer of tungsten-containing enzymes from the result of the similarity of the EPR spectra of the complexes and flavoenzyme from milk. CCDC: 272937.  相似文献   

6.
本文首次报道三元体系Cu(NO3)2-CO(NH2)2-H2O(30℃)和La(NO3)3-CO(NH2)2-H2O(25℃)的等温溶度及饱和溶液、折光率,绘制相应的溶度图及折光率-组成图。体系中发现有组成为Cu(NO3)2·4CO(NH相似文献   

7.
以H6P2Mo18O62·23H2O和(NH4)2C2O4·H2O为原料,首次采用室温固相反应合成出(NH4)6P2Mo18O62·12H2O纳米粉体,并运用元素分析、FTIR、XRD、TEM、TG-DTA和BET等技术对其组成、结构和性能进行了表征。发现(NH4)6P2Mo18O62·12H2O纳米粉体平均粒径为40 nm,保留着杂多阴离子的Dawson结构,具有Dawson结构的特征衍射峰,比表面积为143.9 m2·g-1,在445 ℃以下杂多阴离子有良好的热稳定性。在该固相反应中,研磨和放热反应热能可加速反应物分子的扩散速率和生成物分子的成核速率,使产物粒径减小;反应物含有结晶水和生成物H2C2O4·2H2O对形成小粒径的(NH4)6P2Mo18O62·12H2O纳米粉体起关键作用。  相似文献   

8.
采用低温溶液法合成了含有二铵阳离子结构的新型二维层状结构的有机/无机杂化钙钛矿材料(NH3C6H12NH3) CuCl4。采用元素分析、红外光谱、X射线衍射和紫外-可见光吸收光谱等手段对其结构与性能进行了表征。结果表明该材料的紫外-可见吸收光谱吸收峰位于285 nm和387 nm,层间距为1.18 nm。二铵阳离子的引入,使有机层+NH3C6H12NH3+与2个相邻的无机框架CuCl42-分别通过较强的氢键结合在一起,排列更为规整,热稳定性更高。与单铵阳离子结构的杂化钙钛矿材料相比,由于不存在两层有机分子层间较弱的范德华力,(NH3C6H12NH3) CuCl4材料的电阻率为1.36×105 Ω·cm,比单胺结构的杂化钙钛矿材料的电阻率低3个数量级。  相似文献   

9.
通过简便的蒸发方法得到了 2种碱金属磺酸盐非线性光学(NLO)晶体, 即 Li(NH2SO3)和 Na(NH2SO3)。Li(NH2SO3)以极性空间群Pca21(编号 29)结晶。Li(NH2SO3)的结构可以描述为由[LiO4]7-多面体通过共角连接与 NH2SO3-四面体相互连接而形成的三维网络。Na(NH2SO3)以极性空间群 P212121(编号 19)结晶。Na(NH2SO3)的结构可以描述为由扭曲的[NaO6]11-八面体通过共角连接与 NH2SO3-四面体相互连接而形成的三维网络。紫外可见近红外光谱表明, Li(NH2SO3)和 Na(NH2SO3)分别具有 5.25 和 4.81 eV 的大光学带隙。粉末二次谐波发生(SHG)测量显示, Li(NH2SO3)和 Na(NH2SO3)的 SHG 强度分别为 KH2PO4的 0.32 倍和 0.31倍。第一原理计算证实, 非线性光学性能主要来自氨基磺酸阴离子和碱金属氧阴离子多面体的协同作用。  相似文献   

10.
沉淀法制备不同形貌和结构的纳米BiVO4   总被引:1,自引:0,他引:1  
采用液相沉淀法,通过选择不同起始原料并控制反应温度和pH值,制备得到不同形貌和结构的纳米BiVO4。采用X-射线衍射(XRD)、透射电子显微镜(TEM)和紫外-可见吸收光谱(UV-Vis)技术对产物进行分析表征。结果表明,采用NH4VO3作V源,室温下可直接制备得到结晶好的四方晶系硅酸锆型BiVO4球形纳米颗粒,提高反应液pH值或升高温度,可得到单斜晶系白钨矿型BiVO4,采用NaVO3作为V源,室温下可直接得到单斜晶系白钨矿型片状BiVO4。加入不同类型表面活性剂则得到不同形貌的BiVO4。  相似文献   

11.
The crystal structure of LaIr4B4 has been refined from single crystal counter data. LaIr4B4 is tetragonal,P42/n,Z=2, isotypic with NdCo4B4, |F|/|F o|=0.039 for 312 independent reflections [|F o|>2 (F o)]. ThIr4B4 and ThOs4B4 also belong to the NdCo4B4-type structure. URu4B4 and UOs4B4 were found to crystallize with LuRu4B4-type structure. The crystal chemistry of (RE)T 4B4-phases is discussed and simple geometric relations are shown to exist between them.Dedicated to Prof.B. T. Matthias in celebration of his 60th birthday.  相似文献   

12.
4-巯基-4-脱氧-4'-去甲表鬼臼毒素的立体控制合成   总被引:2,自引:0,他引:2  
4-巯基-4-脱氧-4'-去甲表鬼臼毒素是合成4位硫取代的4'-去甲表鬼臼毒素的关键中间体,由4'-去甲表鬼臼毒素与硫化氢在BF~3·Et~2O存在下立体控制制备,也可通过以NH~3/CH~CN选择性 地水解4-乙酰硫基-4-脱氧-4'-去甲表鬼臼毒素而制备.  相似文献   

13.
《Liquid crystals》1997,23(1):9-16
Two families of liquid crystalline compounds have been synthesised, the 4-butyl-4- alkoxyazobenzenes and the 4-pentyl-4-alkoxyazobenzenes; for the second family results are presented for the first time for alkoxy chains longer than butyl. The results for both families have been obtained up to the octadecyl homologues. In both families, on the basis of DSC, polarizing microscopy and thermo-optical analysis, a rich polymorphism has been detected (maximum tetramorphism). The smectic properties start with the hexyl derivative (for the butyl family) and with the heptyl derivative (for the pentyl family). Strong odd-even effects for the temperatures of clearing in both groups of compounds were detected. Our results are compared with those of de Jeu et al. and of Adomenas et al. for the 4-butyl-4- alkoxyazobenzenes, for which only one smectic modification was described.  相似文献   

14.
Hamad Z Alkhathlan 《Tetrahedron》2003,59(41):8163-8170
Cyclization of 2-hydroxyacetophenone hydrazones with triphosgene resulted in the formation of 4-methylene-1,3-benzoxazinones. These compounds were converted to 4-alkoxy-4-methyl-1,3-benzoxazinones and 4-fluoromethyl-4-methoxy-1,3-benzoxazinones upon treatment with alcohols under refluxing conditions and F-TEDA-BF4 in acetonitrile and methanol, respectively.  相似文献   

15.
Ab initio calculations have been performed on B4H4, B4Cl4 and B4F4 in order to aid our understanding of the bonding in these compounds, which is presumably based on a tetrahedral boron cage. This cage has only 8 electrons and so is less than that expected on the basis of the usual framework electron counting rules. Basis sets with polarisation functions were used at the SCF, CI and CPF levels of theory to confirm that the T d structures are indeed more stable than the D 4h ones. Davidson-Roby population analyses were able to show that many factors, including 3-centre 2-electron bonding and backbonding from the ligand to the boron cage, are of importance in determining the relative stability of the three compounds, of which B4Cl4 is the only one that has yet been observed experimentally.  相似文献   

16.
17.
Methods for the synthesis of hitherto unknown 4-fluoro-4-nitroisoxazolines by fluorination of 4-nitroisoxazoline salts with FClO3 in MeOH and 4-fluoroisoxazoles by treatment of fluoronitroisoxazolines bearing the hydrogen atom bound to the C(5) atom of the isoxazole ring with MeONa in MeOH were developed.  相似文献   

18.
19.
5-Methyl- and 6-methyl-2-phenyl-2H-indazole-4,7-diones were condensed with 2-aminobenzenethiol or 6-substituted-3-aminopyridine-2(1H)thiones 4 to produce a new type of 5-methyl-2-phenyl-4H-pyrazolophenothiazin-4-ones or 8-substituted-7-aza-5-methyl-2-phenyl-4H-pyrazolophenothiazin-4-one derivatives. From 6-bromo-2,5-dimethyl-1,3-diphenyl-2H-isoindole-4,7-dione and 4 8-substituted-7-aza-2,5-dimethyl-1,3-diphenyl-4H-pyrrolophenothiazin-4-one derivatives were also prepared.  相似文献   

20.
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