排序方式: 共有34条查询结果,搜索用时 15 毫秒
1.
Zhang Yongqiang Wang Baiquan Xu Shansheng Zhou Xiuzhong Sun Jie 《Transition Metal Chemistry》1999,24(6):722-725
Reactions of diiron complexes (E)[5-t-BuC5H3)Fe(CO)]2(-CO)2 [E = Me2Si (1), Me2SiSiMe2 (2), and Me2SiOSiMe2 (3)] with iodine in CHCl3 yielded diiodide complexes (E)[5-t-BuC5H3)Fe(CO)2I]2 [E=Me2Si (5), Me2SiSiMe2 (6), and Me2SiOSiMe2 (7)]. Like (1–3), complexes (5–7) also exists as mixtures of cis and trans isomers even though the Fe–Fe bond in (1–3) has been cleaved. When the pure isomers (1–3) reacted with iodine respectively in CHCl3, the cis isomers (1c–3c) yielded only the cis products (5c–7c), whereas the trans isomers (1t–3t) yielded only the trans isomers (5t–7t). This indicates that iodination of bridged diiron complexes is stereospecific. Similar treatment of trans-(Me2Si)[{5-t-(heptyl)C5H3}Fe(CO)]2(-CO)2 (4t) with iodine gave only the trans product (Me2Si)[{5-t-(heptyl)C5H3}Fe(CO)2I]2 (8t). The molecular structure of (5t) was determined by X-ray diffraction. 相似文献
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Nuancheng Wang Prof. Dr. Bin Li Prof. Dr. Haibin Song Prof. Shansheng Xu Prof. Dr. Baiquan Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):358-364
The mechanism of the [(Cp*MCl2)2] (M=Rh, Ir)‐catalyzed oxidative annulation reaction of isoquinolones with alkynes was investigated in detail. In the first acetate‐assisted C? H‐activation process (cyclometalated step) and the subsequent mono‐alkyne insertion into the M? C bonds of the cyclometalated compounds, both Rh and Ir complexes participated well. However, the desired final products, dibenzo[a,g]quinolizin‐8‐one derivatives, were only formed in high yield when the Rh species participated in the final oxidative coupling of the C? N bond. Moreover, a RhI sandwich intermediate was isolated during this transformation. The iridium complexes were found to be inactive in the oxidative coupling processes. All of the relevant intermediates were fully characterized and determined by single‐crystal X‐ray diffraction analysis. Based on this mechanistic study, a RhIII→RhI→RhIII catalytic cycle was proposed for this reaction. 相似文献
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本文研究了开链及环状硅氢化合物中硅原子上取代基的电子效应和立体效应对Si-H键伸缩振动频率的影响。 相似文献
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We have recently reported a novel rearrangement reaction involving an intramolecular metathesis between M-M and Fe-Fe bonds in the dinuclear iron complexes (Me2MMMe2)[η5-C5R4)Fe(CO)]2(μ-CO)2 (M=Si, Ge; R=H, Me):[1-5].In order to extend the applied range of the rearrangement reaction we tried to synthesize the digermyl briged diruthenium analogues. The results showed a great difference between them. 相似文献
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采用1,6-二氯十二甲基六硅烷与对溴苯甲醚的格氏试剂反应制得了标题化合物。对其进行了结构分析。X射线衍射分析表明,该晶体属单斜晶系,分子是中心对称的,化合物呈交叉锯齿型稳定构象。 相似文献
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A hybrid material of graphene oxide (GO) sheets beaded with ZnO nanoparticles was prepared. The material extends over a few hundred square nanometers, in which the ZnO nanoparticles (average diameter (∼5 nm)) are dispersed evenly on the GO sheet. Both the surface photovoltage or surface photocurrent intensity for the material are much stronger than for pure ZnO nanoparticles, meaning that the free charge carriers can effectively be transferred from ZnO nanoparticles to GO sheets, which can serve as a probe to monitor the electron transfer from excited ZnO to GO. Anchoring ZnO nanoparticles on two dimensional carbon nanostructures such as GO can pave a way towards the design of ordered nanostructure assemblies that can harvest light energy efficiently. 相似文献
7.
Wang B Mu B Deng X Cui H Xu S Zhou X Zou F Li Y Yang L Li Y Hu Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(2):669-679
A series of cycloalkylidene-bridged cyclopentadienyl metallocene complexes, [(CH(2))(n)C(C(5)H(4))(2)MCl(2)] (M = Ti, n = 4 (4), 5 (5), 6 (6); M = Zr, n = 4 (7), 5 (8), 6 (9); M = Hf, n = 4 (10), 5 (11), 6 (12)), have been synthesized and applied to ethylene polymerization after activation with methyl aluminoxane (MAO). The cycloalkylidene-bridged titanocene catalysts exhibit much higher activities than the corresponding zirconocene and hafnocene analogues, and have the highest activities at higher temperatures. In comparison, the silacyclopentylidene-bridged metallocene complexes [(CH(2))(4)Si(C(5)H(4))(2)MCl(2)] (M = Ti (13), Zr (14)) and isopropylene-bridged metallocene complexes [Me(2)C(C(5)H(4))(2)MCl(2)] (M = Ti (15), Zr (16)) have also been synthesized and applied to ethylene polymerization. In both cases, the titanocene complexes show much higher activities than the corresponding zirconocene analogues, especially at a lower temperature. The molecular structures of complexes 4-9 have been determined by X-ray diffraction. The structure-activity relationships, especially the effects of the bridges of ansa-metallocene complexes, are discussed. 相似文献
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Prof. Dr. Bin Li Huiliang Feng Nuancheng Wang Jianfeng Ma Prof. Dr. Haibin Song Prof. Shansheng Xu Prof. Dr. Baiquan Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12873-12879
The mechanism of [{RuCl2(p‐cymene)}2]‐catalyzed oxidative annulations of isoquinolones with alkynes was investigated in detail. The first step is an acetate‐assisted C? H bond activation process to form cyclometalated compounds. Subsequent mono‐alkyne insertion of the Ru? C bonds of the cyclometalated compounds then takes place. Finally, oxidative coupling of the C? N bond of the insertion compounds occurs to afford Ru0 sandwich complexes that undergo oxidation to regenerate the catalytically active RuII complex with the copper oxidant and release the desired dibenzo[a,g]quinolizin‐8‐one derivatives. All of the relevant intermediates were fully characterized and determined by single crystal X‐ray diffraction analysis. The [{RuCl2(p‐cymene)}2]‐catalyzed C? H bond functionalization of isoquinolones with alkynes to synthesize dibenzo[a,g]quinolizin‐8‐one derivatives through C? H/N? H activation was also demonstrated. 相似文献
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