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自1978年顺铂成功地被开发成癌症临床治疗药物以来,金属配合物作为小分子抗癌药物的开发成为人们的研究热点。其中,氮杂环卡宾能与多种过渡金属中心形成稳定的共价键,这种特殊的稳定性使得金属氮杂环卡宾配合物具有被开发成药物的潜能。近年来,金属氮杂环卡宾配合物被发现具有良好的抗癌活性,激发了广大无机药物化学研究者的研究热情。综合笔者课题组在金属氮杂环卡宾抗肿瘤配合物方面的前期研究,本文将对银、金、铑和铂氮杂环卡宾配合物的抗肿瘤活性及作用机制进行综述,以期为新型金属氮杂环卡宾抗肿瘤化合物的设计合成提供参考。 相似文献
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由于N-杂环卡宾配体(NHCs)的独特性能,N-杂环卡宾过渡金属配合物在均相催化等方面取得了重要应用,但是其合成方法却发展缓慢。本文综述了N-杂环卡宾过渡金属配合物合成方法的最新研究进展,介绍了富电子烯烃裂解反应、游离NHC直接配位反应、配体底物的脱质子原位反应、卡宾加合物热解反应、金属交换转移反应和C2-X(X为甲基、卤原子或氢原子)键氧化加成反应等合成N-杂环卡宾过渡金属配合物的主要方法,此外本课题组还首次发现了金属粉末法,该法可用于规模化合成铁、钴、镍、铜等第一过渡系金属NHC配合物。 相似文献
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近年来,氮杂环卡宾作为有机小分子催化剂在共催化领域取得了飞速发展,氮杂环卡宾通过与Lewis酸、Brønsted酸、Brønsted碱、氢键等不同催化模式相结合,可以有效提升惰性底物的活性和催化体系的立体控制能力,该策略已经成为复杂手性分子骨架合成的重要工具.相对而言,由于氮杂环卡宾与过渡金属的强配位能力,其与过渡金属共催化反应依旧是氮杂环卡宾在共催化领域中长期存在的挑战性工作.目前,氮杂环卡宾在与钯、铜和钌的共催化反应中取得了重要进展,通过配体和反应体系中碱性强弱的调控,可以有效实现氮杂环卡宾与过渡金属配位的可控调节,避免催化剂失活的同时提升反应体系催化活性.这一策略已经被成功用于一些活性分子骨架构建.本文将对该领域中的研究进展进行介绍. 相似文献
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重氮化合物是一类非常重要的有机合成中间体, 它在有机合成化学以及药物设计研发、化学生物学、材料化学等领域具有重要的应用价值. 传统的重氮化合物的转化反应类型包括了Wolff重排, 经由过渡金属卡宾或者类卡宾中间体的插入反应, 催化的环丙烷化反应, 以及近年来发展的过渡金属催化的经由卡宾中间体的交叉偶联反应等. 重氮化合物除了发生作为卡宾前体的经典反应之外, 它们还可以经由氮基团保留的转化过程, 在目标分子中保留重氮基团或者其它含氮原子的官能团. 该种策略提供了一种高效而选择性地构筑含氮功能分子、尤其是官能化的氮杂环的合成途径. 其中, 不对称的C-N键的选择性构筑, 以及不对称的氮杂环分子的组装, 仍然具有重要的合成价值和重大的挑战意义. 本篇综述根据反应的机理和类型, 将这部分研究工作分为六部分内容进行介绍. 相似文献
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N-杂环卡宾(NHCs)及其金属配合物是有机金属化学学科的研究热点,在催化领域获得广泛应用。向NHCs杂环添加新颖官能团,构建复杂NHCs及其金属配合物可实现不同催化性能。糖类化合物具有生物相容性、水溶性、手性、无毒副作用且广泛存在于自然界,将糖取代基引入NHCs不仅可以改善水溶性,还可以引入手性元素。糖基-NHCs及其金属配合物在催化和药化领域显现出巨大潜力。本文就国内外含单糖D-吡喃葡萄糖、D-吡喃半乳糖、β-氨基葡萄糖、氨基半乳糖和氨基甘露糖等糖基衍生NHCs前体及NHCs金属配合物的重要研究成果进行了综述。根据糖基稠环碳原子与NHCs杂环的连接方式,将NHCs及其金属配合物分为5种类型,包括C-1、C-2、C-3、C-6及其他。从糖基-NHCs及其过渡金属配合物的合成、结构和催化性能方面进行了深入讨论,着重介绍了糖基和NHCs及其金属配合物在催化性能之间的关联性,并进行了简短的评述。最后,对糖基-NHCs及其过渡金属配合物的催化性能特别是在不对称反应中的应用前景及其影响因素进行了展望。 相似文献
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在过渡金属有机化学中,含过渡金属-主族元素(C,N,P)双键的卡宾配合物化学具有重要地位.它不仅对人们理解过渡金属和主族元素的成键理论很重要,而且这类配合物具有一些很好的、以及特征性的反应和催化性能.在过去的30年中,人们在含稀土金属-主族元素(C,N,P)单键的稀土金属烷基、胺基配合物以及膦基配合物化学研究上取得了很好的进展.稀土卡宾配合物化学是相关研究工作者接下来需要和渴望开拓的一个重要领域.人们在这一方面进行了积极的探索,合成得到了一些稀土桥联卡宾配合物和稀土卡宾配合物的模拟物.虽然它们离稀土金属-主族元素双键的稀土末端卡宾配合物有差距,但可以为稀土末端卡宾配合物的研究提供一些线索.本论文论述了这方面的研究成果,以及最近在稀土末端氮卡宾配合物上的一个突破. 相似文献
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自从1991年Arduengo第一次分离得到稳定的游离N-杂环卡宾以后,N-杂环卡宾金属络合物的研究在近几年来得到了迅速的发展。N-杂环卡宾的反应性能较高,它们与周期表中几乎所有的元素都能发生反应。N-杂环卡宾金属络合物对许多反应有催化作用,它们是一类有潜在应用价值的催化剂。本文对近年来相关的研究成果进行了综述。 相似文献
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N杂环卡宾的反应性能较高,与周期表中几乎所有的金属都能发生反应形成稳定的配合物.主要阐述了N杂环卡宾的结构与类型,其金属配合物的合成方法及在化学反应中的催化作用和应用前景. 相似文献
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Hobbs MG Knapp CJ Welsh PT Borau-Garcia J Ziegler T Roesler R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(48):14520-14533
A series of rhodium complexes, [Rh(cod)(NHC-F(x))(OH(2))] (cod = 1,5-cyclooctadiene; NHC = N-heterocyclic carbene), incorporating anionic N-heterocyclic carbenes with 2-tert-butylmalonyl backbones and 2,6-dimethylphenyl (x = 0), 2,6-difluorophenyl (x = 4), 2,4,6-trifluorophenyl (x = 6), and pentafluorophenyl (x = 10) N,N'-substituents, respectively, has been prepared by deprotonation of the corresponding zwitterionic precursors with potassium hexamethyldisilazide, followed by immediate reaction of the resulting potassium salts with [{RhCl(cod)}(2)]. These complexes could be converted to the related carbonyl derivatives [Rh(CO)(2)(NHC-F(x))(OH(2))] by displacement of the COD ligand with CO. IR and NMR spectroscopy demonstrated that the degree of fluorination of the N-aryl substituents has a considerable influence on the σ-donating and π-accepting properties of the carbene ligands and could be effectively used to tune the electronic properties of the metal center. The carbonyl groups on the carbene ligand backbone provided a particularly sensitive probe for the assessment of the metal-to-ligand π donation. The ortho-fluorine substituents on the N-aryl groups in the carbene ligands interacted with the other ligands on rhodium, determining the conformation of the complexes and creating a pocket suitable for the coordination of water to the metal center. Computational studies were used to explain the influence of the fluorinated N-substituents on the electronic properties of the ligand and evaluate the relative contribution of the σ- and π-interactions to the ligand-metal interaction. 相似文献
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The chemistry of heterocyclic carbenes has experienced a rapid development over the last years. In addition to the imidazolin-2-ylidenes, a large number of cyclic diaminocarbenes with different ring sizes have been described. Aside from diaminocarbenes, P-heterocyclic carbenes, and derivatives with only one, or even no heteroatom within the carbene ring are known. New methods for the synthesis of complexes with N-heterocyclic carbene ligands such as the oxidative addition or the metal atom template controlled cyclization of beta-functionalized isocyanides have been developed recently. This review summarizes the new developments regarding the synthesis of N-heterocyclic carbenes and their metal complexes. 相似文献
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Roselló-Merino M Díez J Conejero S 《Chemical communications (Cambridge, England)》2010,46(48):9247-9249
Pyridinium 2-carboxylates decompose thermally in the presence of a variety of late transition metal precursors to yield the corresponding 2-pyridylidene-like complexes. The mild reaction conditions and structural diversity that can be generated in the heterocyclic ring make this method an attractive alternative for the synthesis of 2-pyridylidene complexes. IR spectra of the Ir(i) carbonyl compounds [IrCl(NHC)(CO)(2)] indicate that these N-heterocyclic carbene ligands are among the strongest σ-electron donors. 相似文献
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The syntheses of two tetravalent uranium alkoxide-carbene complexes are reported, [UIL3], and [UL4] where L = OCMe2CH2[1-C(NCHCHNiPr)]. The latter shows dynamic behaviour of the alkoxycarbene ligands in solution at room temperature, and the crystal structure of [UL4] shows that one carbene group remains uncoordinated. The unbound N-heterocyclic carbene group is trapped by a range of reagents such as 16-valence-electron metal carbonyl fragments and BH3 moieties, forming, for example, [UL3(mu-L)W(CO)5], [UL2(mu-L)2Mo(CO)4], and [UL(n)(L-BH3)(4-n)] (n = 1-4), demonstrating the potential for these hemilabile electropositive metal-carbene complexes to participate in the bifunctional activation of small molecules. 相似文献
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Milosevic S Brenner E Ritleng V Chetcuti MJ 《Dalton transactions (Cambridge, England : 2003)》2008,(15):1973-1975
The first examples of mixed metal trinuclear clusters carrying N-heterocyclic carbene (NHC) ligands were isolated from reactions of the complexes [Ni(NHC)ClCp] [NHC = bis-(2,6-diisopropylphenyl)- or bis-(2,4,6-trimethylphenyl)-imidazol-2-ylidene] with [Mo(CO)(3)Cp](-); the unsaturated 46-electron clusters have triangular MoNi(2) cores and the reaction pathway activates usually inert Ni-Cp and Ni-NHC bonds. 相似文献
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Ray L Barman S Shaikh MM Ghosh P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(22):6646-6655
Two new trans- and cis-[(NHC)(2)PdX(2)] (X=Cl, Br) complexes of N/O-functionalized N-heterocyclic carbenes employed in a highly convenient amine-free Sonogashira cross-coupling reaction in air in a polar mixed aqueous medium are reported. Specifically, the trans-[{1-benzyl-3-(3,3-dimethyl-2-oxobutyl)imidazol-2-ylidene}(2)PdBr(2)] (3) and cis-[{1-benzyl-3-(N-tert-butylacetamido)imidazol-2-ylidene}(2)PdCl(2)] (4) complexes effectively catalyzed the Sonogashira cross-coupling reaction of aryl iodides with substituted acetylenes in air in a mixed solvent (DMF/H(2)O, 3:1 v/v) under amine-free conditions. Interestingly, these trans- and cis-[(NHC)(2)PdX(2)] (X=Cl, Br) complexes, with two N-heterocyclic carbene ligands, exhibited superior activity compared with the now popular PEPPSI (pyridine enhanced precatalyst preparation, stabilization and initiation)-themed analogues, trans-[(NHC)Pd(pyridine)X(2)] (X=Cl, Br), 3 a and 4 a, with one N-heterocyclic carbene ligand and a "throw away" pyridine ligand in a trans disposition to each other. The higher activities of 3 and 4 compared with PEPPSI analogues 3 a and 4 a are attributed to more-electron-rich metal centers, as revealed by DFT studies, in the former complexes and is in concurrence with a more electron-rich metal center being effective in facilitating the oxidative addition of aryl halide, often a rate-determining step in palladium-mediated cross-coupling reactions. Complexes 3 and 4 were prepared from the corresponding silver analogues by transmetalation with [(cod)PdCl(2)], whereas the corresponding PEPPSI analogues 3 a and 4 a were obtained directly from the imidazolium halide salts by reaction with PdCl(2) in pyridine in the presence of K(2)CO(3) as base. 相似文献
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吴兆轩 Heriberto Diaz Velazquez 闵梦蝶 原晔 Hussein A. Younus 陈建 Bibimaryam Mousavi Francis Verpoort 《化学通报》2015,78(3):220-225
近年来,催化CO2合成精细化学品的研究备受关注。本研究在温和条件下利用金属双氮杂环卡宾催化剂实现CO2与末端炔烃的直接羧化反应,并提出合理的催化机理。首先,合成制备了铜基、银基两种金属双氮杂环卡宾催化剂,实验证明银双氮杂环卡宾配合物具有较好催化活性。通过改变环境条件和底物种类,对反应条件及催化剂底物适应性进行了探究,利用核磁共振谱仪表征产物分子结构并计算直接羧化反应的催化产率。结果表明,适宜催化条件为:1.2eq Cs2CO3作为添加剂、1大气压、室温、无水溶剂和1(mmol)%催化剂用量。银基金属催化剂活性较铜基催化剂高并具有广泛的底物适应性,对苯乙炔的催化产率高达93%;对乙炔气体同样具有良好的催化活性。此类催化剂具有优良的催化活性,能催化合成丙炔酸等重要医药中间体,在工业应用上具有极大潜力和广阔前景。 相似文献