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本文研究了在双(新 基环戊二烯基)二氯钛催化下异丙基溴化镁与芳基酮或酯和α,β-不饱和酮或酯的反应, 发现还原反应中优势, (NMCp)2-TiCl2催化下格氏试剂对酯的还原, 其产物取决于催化剂的量, 同时, 还改进了双(新 基环戊二烯基)二氯钛的合成方法, 本文还提及了反应可能通过自由基历程。 相似文献
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某些有机钛芴的合成及性质研究 总被引:2,自引:0,他引:2
2,2′二溴联苯衍生物与正丁基锂发生溴-锂交换反应,生成的二锂化合物与二氯二茂钛、二氯二(甲基环戊二烯基)钛或二氯二茚钛作用,得到9种新的有机钛。芴进行了结构测定,并研究了5,5-二茂钛茚的反应性能。 相似文献
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双环戊二烯基钛衍生物的水相化学及双环戊二烯基二水扬酸钛的晶体结构 总被引:2,自引:0,他引:2
(RCp)2TiCl2的乙酰丙酮体系在水相中与硫氰酸钾,吡咯烷基二硫代氨基甲酸钠,取代苯甲酸钠等反应,合成得到相应的(单)双环戊二烯基(或甲基环戊二烯基)钛衍生物,双环戊二烯基二水杨酸钛单晶的结构分析表明,水杨酸作为单齿配体通过羧基氧原子与钛键联。 相似文献
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本文介绍在缓和条件下, 二羰基二茂钛和酚类反应是合成二芳氧基二环戊二烯基钛的新途径, 得到的新化合物都经过元素分析和^1HNMR测定。 相似文献
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关于钛杂环化合物的合成与反应,在文献中曾有一些报道。这类化合物,无论在有机合成上或对于阐明某些有机化学反应和催化聚合机理,都具有重要的作用。这类钛杂环化合物的合成,通常是用二氯二茂钛与双碱金属 相似文献
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超声波作用下羰基化合物的还原偶联反应 总被引:5,自引:0,他引:5
超声波在一些有机反应中有明显的促进作用「“,Luche等认为超声波的作用有两种主要类型[’j.一类是涉及电子转移的自由基或离子一自由基型反应,由于超声波的空化作用所产生的局部高温高压可以促进电子转移,从而明显地加快反应速度;对大多数离子型反应,超声波只能起到机械的物理作用.我们曾报道偕二卤化合物在Li、Na、Mg等金属作用下产生卡宾的反应是单电子转移过程,该反应可由于超声辐射而大大加速[‘];而在芳基叔脚的断裂反应中,超声波可以促进三苯基俄与金属馊反应生成二苯基脚负离子,但对它进一步的亲核取代反应却没有明… 相似文献
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钛有机化合物在有机合成中的重要用途是为大家所熟知的,例如Ziegler-Natta催化剂.本文着重叙述近二年来(1979—1980)钛有机化合物在精细有机合成中的应用。 1.格氏反应中的添加剂.将过渡金属盐加到格氏反应中可以改变反应的进程,这是近 相似文献
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The work is devoted to the ionic coordination polymerization of vinyl cyclohexane. During the polymerization of vinyl cyclohexane, side reactions (viz. isomerization into unreactive isomers with internal double bond and transformation of monomer into ethylcyclohexane) occur on complex organometallic catalysts. A procedure has been developed for studying the kinetics of vinyl cyclohexane transformation by analytical gas-liquid chromatography. The effects of various catalytic systems and their individual components on the rates of these reactions have been investigated. From the experimental data, a reaction mechanism has been suggested. It is supposed that ethylcyclohexane is formed by catalytic hydrogenation of monomer with hydrogen evolved during formation of organometallic complex, as well as by the decomposition of the products of the interaction of vinyl cyclohexane with organo-aluminium compounds or titanium derivatives. Most of the isomers with internal double bond (exo- and endocyclic) are formed by a mechanism involving π-bonded intermediates between a monomer and a transition metal and the subsequent σ-alkyl or π-allylic intra- or intermolecular hydrogen transfer. 相似文献
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Namdu Kim 《Tetrahedron letters》2004,45(38):7057-7059
Palladium nanoparticles were generated from tetrakis(triphenylphophine)palladium in a mixture of tetra(ethylene glycol) and tetramethoxysilane (or titanium(IV) isopropoxide), then encapsulated in silica matrix (or titania matrix) by the treatment with water. The resulting heterogeneous material showed high catalytic activity in the hydrogenations of various alkene and alkynes and in the carbon-carbon cross-coupling reactions such as the Suzuki-Miyaura, the Sonogashira, the Heck-Mizoroki, and the Stille reactions. 相似文献
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微波辐射下以取代苯胺1, 2-溴芳基乙酮2为原料, 在无催化剂条件下一步合成了一系列2-取代吲哚3. 该方法具操作简单、反应时间短、产率高等特点. 相似文献
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A. L. Tchougreff 《International journal of quantum chemistry》1996,58(1):67-84
A general scheme for theoretical treatment of organometallic reactivity is proposed. It is based upon the notion that the reactivity of a molecule is strongly affected by its coordination to metal-containing fragments. Based upon this idea we describe the large-scale organometallic reactions as reactions of the ligands in the coordination spheres of transition metal complexes. We propose here a quantum mechanical framework for analysis of effects of coordination on the reactivity and give several examples of qualitative energy profiles for reactions in the ligand spheres of transition metal complexes. © 1996 John Wiley & Sons, Inc. 相似文献
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《Journal of Molecular Catalysis #》1994,86(1-3):179-204
The synthesis, characterization and catalytic properties of new materials obtained by reaction of organometallic complexes of groups IIb, IVa, and VIa with the surface of metallic particles are reviewed. Two types of materials may be obtained by surface organometallic chemistry on metals: metal particles covered with organometallic fragments, and bimetallic particles of predetermined composition. Characterization of the organometallic fragments on the metal particles has demonstrated their thermal stability. These particles covered with surface organometallic fragments are new catalytic materials, highly selective in several reactions such as the hydrogenation of α,β-unsaturated aldehydes, ethyl pyruvate, nitrobenzene, acrylonitrile, and olefins. The bimetallic particles without organometallic fragments are also highly active and selective for a variety of reactions such as hydrogenolysis of various alkanes and hydrogenolysis of esters. For these systems, the concept of “site isolation” has been advanced to account for the high selectivity of the reactions. 相似文献
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ESR method was used to elucidate the mechanism of the reactions of alkyl, allyl or benzyl halides with dicyclopentadienyldicarbonyl titanium. The paramagnetic [intermediates of the reactions were identified during the course of the reactions. The reaction mechanism based on ESR findings and the products analyses is postulated to operate on radical pathways. When alkyl halides were used to react with the organometallic compound 1, the intermediate found was [Cp2Ti(CO)X] (C), and the main product was identified to be dicyclopentadienyl-acyl-halo titanium (3), an insertion of TiCO into R-X, i.e. [Cp2Ti-C(0)R] X. When allyl or benzyl halides were used, the intermediate found was [Cp2TiX] (B), and the main products were identified to be the dicyclopentadienyl titanium dihalides and the coupling products of allyl or benzyl groups. 相似文献
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The effect of solvent upon the rates and mechanisms or organometallic rections. : I. General aspects
The data reported to date on the effect of solvent upon the rates and mechanisms of organometallic reactions have been analysed and discussed and indicate that the effect is very complex. The analysis also shows that there is no overall explanation for the effect and that indeed such an explanation seems at present to be non-existent.It is suggested that the problem may be successfully approached through a study of the effect of the solvent upon the redistribution of organic groups between organometallic molecules. In these reactionis, not only the kinetics of the reactions in various solvents should be studied but also identification of the organometallic complexes is essential as well as the electronic structures and geometries of the complexes in the crystalline phase and in solution. 相似文献