查询词典 carbene

The results indicated that the high level density functional theory calculations can be used to predict the 13C chemical shifts of the modified nanotubes. The calculated results also provided the characteristic chemical shifts values of nitrene (superscript -), carbene (superscript -) and 1,2- and 1, 4-fluorinated nanotubes, which would be helpful for experimental spectrogram assignments. Combined with NMR experiments, these predicted characteristic chemical shifts can be further used to monitor the addition mechanism and the extent of surface modifications on nanotubes.

研究表明高精度的密度泛函理论计算能够用来预测纳米管的13C化学位移，理论研究的结果揭示了氮烯、卡宾以及1，2和1，4氟化的单壁纳米管的若干13C信号特征化学位移值，为实验NMR谱图的归属提供了一定的依据，并且可通过与实验相结合来监测表面官能化碳纳米管加成反应是否发生以及确认其加成方式。

This thesis consists of three main parts of the research work on the syntheses, structures and reactivities of the olefin-coordinated transition metal carbene and carbyne complexes. In chapter 1, on the basis of our previous research works on the reacitivites of the cationic carbyne complexes of transition metals with metalcarbonyl anions, we explored the reactions of the cationic carbyne complexes of manganese (1) and rhenium (2) with polymetalcarbonyl anions, and developed a new method for the preparations of heternuclear trimetal bridging carbyne complexes.

本论文对烯烃配位的过渡金属卡宾和卡拜络合物的合成、结构和反应性能进行了研究，主要进行了如下三方面的工作：第一章在本小组过去的研究基础上，进一步考察锰和铼的阳离子卡拜络合物1和2与羰基金属阴离子化合物的反应，用来合成异核多金属桥卡拜络合物，发展合成多金属桥卡拜络合物的新方法和新路线。

The mechanism of cycloaddition reaction between singlet carbene and Formylchloride has been investigated by using ab initio MO theory of the restricted Hartree-Fock at HF/3-21G~* level.

用限制的H artree-Fock从头算分子轨道理论研究了单重态卡宾与甲酰氯环加成反应的机理。

Reaction of NaOAr, SmCl_3 and aryloxo-functional N-heterocyclic carbene precursor [HO-4, 6-di-~tBu-C_6H_2-2-CH_2{CHMe}]Cl in 4:1:1 molar ratio in THF in one-pot hadnt afforded an anionic phenoxide complex of samarium (5) supported by a bridged bisphenoxo through the cleavage of aryloxo-functional N-heterocyclic carbenes.

4将NaOAr、SmCl_3和[HO-4，6-di-~tBu-C_6H_2-2-CH_2{CHMe}]Cl以4∶1∶1摩尔比，采用一锅煮的方法，希望得到芳氧基功能化的氮杂环卡宾稀土芳氧配合物没有取得成功，而是得到了断裂的产物O-4，6-di-~tBu-C_6H_2-2-[CH{NNMe}[(O-4，6-di-~tBu-C_6H_2)_2CH_2][O-2，4-di-~tBu-C_6H_3]Sm(5)。

Electron-withdrawing groups decrease the reactivity of benzylic C - H whileelectron-releasing groups enhance its reactivity. This is consistent with the well-knownelectron-demanding character of the Rh-carbene complex.

从相对速率的数值〓可以看到，吸电子基使苯甲位反应活性降低，给电子基使苯甲位反应活性增大，这和Rh-卡宾的亲电性一致。

With NMR and DFT methods, the Michael additions of alkynyl Fischer carbene complex with a series of substituted pyrazoles as nucleophiles were also studied. All reactions follow the same three-step pathway mechanism described above. Substituents on 3-, 4- and 5- positions of the pyrazolyl ring affect the reaction in the steric and electronic manners, even to change the rate-determining step.

一系列取代吡唑与1-炔基Fischer卡宾化合物的Michael加成反应都遵循前面提出的三步机理，其中吡唑的3-， 4-， 5-位分别从电子效应和立体效应方面不同程度地影响着反应的进行，甚至改变反应的决速步骤。

When diaryl ketones were treated in DMF promoted by samarium metal with TMSCl as activator, diaryl ketones react with DMF followed by a carbene rearrangement to afford benzoins unexpectedly, with benzils were obtained as byproducts, the formation of which may be explained as a result arising from the auto-oxidation of benzoins. Further investigation found the reaction could also proceed smoothly when I〓 was used as an activator. The reaction could occur as well in SmI〓/THF, though benzoins were obtained in relatively low yields.

发现当有活化剂TMSCl存在时，金属钐能有效的促进二芳酮和DMF的发生反应，偶联后发生卡宾重排，意外地得到苯偶姻类化合物，同时伴随着少量的二芳基二酮副产物生成，我们推测二芳基二酮的生成可能从苯偶姻的自氧化而来；进一步的研究表明，用一定量的I〓活化金属钐，该反应也可以顺利的进行，并且可以得到相对更好的实验结果。

Treatment of phosphines with [Ir2Cl] resulted the formation of the products with the phosphine ligand trans to the carbene moiety via substitution of CO.

当膦化物与上述的 [I2Cl]反应时，膦化物会取代反式位置上的CO取代基而形成[Ir(PR3)Cl]。

The coordinated COD of 3 and 4 can be replaced by carbon monoxide to yield the corresponding dicarbonyl species [(C,N-pyN^C-R) M2]BF4 (14, M= Rh; 15, M= Ir). Ligand substitution of 11a by phosphines and azide causes the de-complexation of pyridinyl-nitrogen donor to generate the corresponding carbene rhodium complexes [(C-pyN^C-Mes)RhPR3] (17a, R = Ph, 17b, R = Et) and [RhN3] (19), respectively, indicating the labile nature of steric-hindered pyridinyl-nitrogen donor.

螯合错合物的吡啶配位，可以容易被σ-予体，如卤离子、叠氮阴离子、膦试剂，置换；但是铑与铱金属螫合物与π-酸试剂，如一氧化碳、异腈，则发生COD被置的产物14a与16；与三甲基亚磷酸酯反应时，COD及吡啶均会被取代而得到单芽的三铑-碳烯错合物18；双膦化合物则会取代铑金属上全部的配位基。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。