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51.
Mn2P2S6 single-crystal nanorods with diameters 20-40 nm and lengths up to 1 microm and nanotubes with diameters 40-50 nm and lengths ranging between 110 and 170 nm have been prepared through a low-temperature solvothermal method. They have been characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution (HR) TEM, electron diffraction, energy-dispersive spectrometry analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy. 相似文献
52.
Ge JP Wang J Zhang HX Wang X Peng Q Li YD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(6):1889-1894
Three-dimensional, orthogonal lead sulfide (PbS) nanowire arrays and networks have been prepared by using a simple, atmospheric pressure chemical vapor deposition (APCVD) method. These uniform nanowires (average diameter 30 nm) grow epitaxially from the surface of the initial PbS crystal seeds and form orthogonal arrays and networks in space. The growth mechanism has been explored, and the process was classified as homogeneous, epitaxial growth in the 200 directions. Furthermore, Raman spectra of PbS nanowires are reported here, and their characteristic Raman peak (190 cm(-1), no shoulder) could be used as a unique probe for the study of PbS nanomaterials. 相似文献
53.
A new Ni(Ⅱ) complex [Ni2(salen)2]·(NCS)·NH4 (salen = N,N'-bis(salicylidenea-mino)ethanato) has been prepared and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.8725(13), b = 19.0046(15), c = 20.0583(16) (A), Z = 8, V = 6431.8(9) (A)3, C33H32N6Ni2O4S1, Mr= 726.13, Dc = 1.500 g/cm3, F(000) = 3008, μ = 1.284 mm-1, the final R = 0.0394 and wR = 0.0767 for 4449 observed reflections with Ⅰ>2σ(Ⅰ). The complex involves a N,N'-ethylene-bis(salicylaldiminato) Schiff base, an isothiocyanato anion and an ammonium cation. The nickle(Ⅱ) ion adopts a distorted square coordination geometry with N2O2 set of Schiff base ligand. The complexes are linked into a dimmer via intermolecular hydrogen bonds and the [Ni(salen)] moieties are connected together to form a 2-D layer structure by intermolecular N-H…O hydrogen bonds and π-π stacking. Cyclic-voltammetry method was used to characterize electrochemically the complex. 相似文献
54.
(η^2—C60)[Pt(PPh3)2]8的合成与表征 总被引:6,自引:2,他引:6
C60是高度共轭的宠状结构碳素体.分子结构中六元环间的共价碳碳双键是富电子区,其反应性能与烯键类似,以碳碳双键与中心金属形成η2配位化合物.富勒烯η2配合物的合成及性能研究是当前研究热点之一[1~7].本文在(η2-C60)[Pt(PPh3)2]n(n=1~6)系列研究[7]的基础上制备了(η2-C60)[Pt(PPh3)2]8,并用元素分析、红外光谱和光电子能谱进行鉴定和表征.1实验部分四(三苯基膦)合铂Pt(PPh3)4按文献[8]方法制备;C60纯度为99%;其余试剂均为分析纯.元素分析在ERLA-1106型元素分析仪上进行;光电子能谱在VGESCA… 相似文献
55.
Chiral quaternary ammonium salts derived from cinchonidine have been applied to catalyze the stereoselective iodolactonizations of trans-5-aryl-4-pentenoic acids leading to a mixture of two regioselectively iodolactonized products with fair to excellent yield (37-98%) and moderate enantioselectivity (exo = 42.0% ee, endo = 31.0% ee) under mild conditions. This work is the first example of asymmetric iodolactonization reaction in the presence of less than a stoichiometric amount of chiral reagent. 相似文献
56.
Synthesis of a Photolabeling Probe for the Study of Antiviral Mechanism of Ribavirin 总被引:1,自引:0,他引:1
QiongYouwu XunZHU JinQiaoWAN FanQiQU LingPENG 《中国化学快报》2004,15(8):907-910
Ribavirin has been used in urgency to treat SARS patients recently. In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin. The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism ofribarivin by photolabeling. 相似文献
57.
58.
Qiongyou Wu Fanqi Qu Jinqiao Wan Xun Zhu Yi Xia Ling Peng 《Helvetica chimica acta》2004,87(4):811-819
Ribavirin, the only small molecule available so far for treating hepatitis‐C‐virus infection, was recently used in an emergency context to treat patients with severe acute respiratory syndrome (SARS) in the early stages of the disease. To study the mechanisms responsible for the antiviral effects of ribavirin by using a photolabeling approach, we designed, synthesized, and characterized the azidotriazole nucleosides 1 and 2 as photolabeling probes of ribavirin. These probes were synthesized either by performing nucleophilic substitution of the corresponding bromotriazole nucleoside with NaN3 (Scheme 2) or by directly coupling the azidotriazole with the protected ribose sugar (Scheme 4). The azidotriazole nucleosides 1 and 2 showed a fast, clear‐cut photochemical reaction, which suggests that they are promising candidates for use in photolabeling studies. 相似文献
59.
60.
用质谱技术对钾、钙同位素体系特征参数测定的初探 总被引:1,自引:0,他引:1
报道了用FinniganMAT 2 62质谱技术和同位素稀释法测定了光谱纯CaO和国际二级标准Tahiti(CaCO3)的同位素40 Ca 42 Ca比值以及后者的40 Ca含量 ,RSD分别为 0 .0 2 %和 0 .1 %。对国家钾标样的测定表明 :39K、40 K和41 K同位素丰度分别为 0 .93 2 60± 0 .0 0 1 2、0 0 0 0 1 1 2 0± 0 .0 0 0 0 1 2 9和 0 .0 672 86± 0 .0 0 0 1 2 5。其中39K含量为 0 .1 2 1 72± 0 .0 0 0 2 9,与标准值在误差范围内一致。实验测定结果为在我国开展40 K 40 Ca同位素体系的定年和环境的示踪研究打下了基础 相似文献