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991.
A novel 3D polymeric heteropolynuclear sodium(I) lead(II) complex containing different ligands, [NaPb(ClO4)(en)(NO2)2] was synthesized and characterized by elemental analysis and IR, and 1H‐, 13C‐, and 207Pb‐NMR spectroscopy. The single‐crystal X‐ray data of [NaPb(ClO4)(en)(NO2)2]n established that the complex is a three‐dimensional polymer, [(en)Pb(μ3‐ONO)2Na(μ3‐ONO)2Na(μ‐O2ClO2)Na]n. The Pb and Na atoms have four‐ and eight‐coordinate geometry, respectively. The lone pair of electrons at the PbII atom is ‘stereochemically active’. 相似文献
992.
Double-walled carbon nanotubes (DWNTs) have been synthesized by catalytic chemical vapor deposition (CCVD) over supported metal catalysts decomposed from Fe(CH3COO)2 and Co(CH3COO)2 on mesoporous silica. Bundles of tubes with relatively high percentage of DWNTs, in areas where tubular layered structures could be clearly resolved, have been observed by transmission electron microscopy (TEM). In other areas, crystal-like alignment of very uniform DWNTs was observed for the first time, suggesting that mesoporous silica might play a templating role in guiding the initial nanotube growth. In addition, compatible with nano-electronics research, bridging of catalytic islands by DWNTs has also been demonstrated. 相似文献
993.
合成了金刚烷甲酸与稀土Nd(Ⅲ)和La(Ⅲ)离子配合物, 并测定了配合物的晶体结构. 配合物的组成为[LnL3(HL)(H2O)]2·2EtOH·2H2O (Ln=Nd (1), La (2), HL=金刚烷甲酸). 配合物晶体均属三斜晶系, 空间群为P1, 晶胞参数 配合物(1) a=1.0556(2) nm, b=1.4913(3) nm, c=1.4920(3) nm , α=106.26(3)°, β=93.51(3)°, γ= 97.23(3)°, V=2.2253(5) nm3, Dcal=1.409 g·cm-3, Z=1, F(000)=990, μ(Mo Kα)=1.225 mm-1, Mr=1888.54. 配合物(2) a=1.0453(2) nm, b=1.4971(3) nm, c=1.5052(3) nm, α=106.07(3)°, β=93.58(3)°, γ=97.56(3)°, V=2.2391(5) nm3, Dcal=1.397 g·cm-3, Z=1, F(000)=984, μ(Mo Kα)=1.015 mm-1, Mr=1877.88. 两个配合物属异质同晶, 呈双核结构, Ln(Ⅲ)为九配位, 形成畸变三帽三棱柱配位多面体. 相似文献
994.
QuanliZhu JianYang JiaxinWang ShengfuJi HanqingWang 《天然气化学杂志》2003,12(1):23-30
The performance of uspported and unsupported molybdenum carbide for the partial oxidation of methane (POM) to syngas was investgated.An evaluation of the catalysts indicates that bulk molybdenum carbied has a higher methane conversion during the initial stage but a lower selectivity to CO and H2/CO ratio in the products.The rapid deactivation of the catalyst is also a significant problem.However,the supported molybdenum carbide catalyst shows a much higher methane conversion,increased selectivity and significantly improved catalytic stability.The characterization by XRD and BET specific area measurements depict an improved dispersion of molybdenum carbide when using alumina as a carrier.The bulk or the supported molybdenum carbide exists in the β-Mo2C phase,while it is transformed into molybdenum dioxide postcatalysis which is an improtant cause of molybdenum carbide deactivation. 相似文献
995.
996.
Jesús Castro Paulo Prez Lourido Antonio Sousa‐Pedrares Elena Labisbal Jos Piso Jos Arturo García‐Vzquez 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):m319-m322
The crystal structure of the title compound, [CoCl2(C6H12N2S)2], consists of monomer units of a CoII atom coordinated to two 1‐propylimidazolidine‐2‐thione ligands and to two chloride ions. The heterocyclic thione ligand is monodentate and coordinated to the metal through the thione S atom. The environment around the CoII atom is a slightly distorted tetrahedron. The Co—S bond lengths are 2.341 (2) and 2.330 (2) Å, and the Co—Cl bond lengths are 2.234 (2) and 2.238 (2) Å. The most important point of distortion is the S—Co—S bond angle of only 97.83 (8)°. Intramolecular classical hydrogen bonds are found between the chloride ions and the N—H groups. Additionally, intra‐ and intermolecular non‐classical hydrogen bonds are found. 相似文献
997.
998.
过敏性哮喘患者血清中10种必需微量元素水平的研究 总被引:1,自引:0,他引:1
34例过敏性哮喘患者血清中铁,锌、铜,锰硒铬,钴镍,钡,钼的含量水平与对照组比较,揭示:(1)铁,铜,铬的含量升高;(2)硒,镍,钴、钒的钼的含量降低;(3)锌和锰的含量差异无显著性,P〉0.05。 相似文献
999.
1000.
WANG Hua ZHAO Mi-feng PU Li-mei DING Wei HUANG Yi-bing HOU Rui-zhen ZENG Hong-bin XU Li ZHANG Xue-zhong 《高等学校化学研究》2006,22(6):721-726
IntroductionA characteristic tripeptide sequence Arg-Gly-Asp(RGD) that is found within fibronectin and other rela-ted adhesion molecules in extracellular matrices(ECM)has received considerable attention from researcherssince it was proved to be a recognit… 相似文献