负载型N-杂环卡宾催化剂在有机反应中的最新研究进展

负载型氮杂环卡宾金属催化剂兼具氮杂环卡宾金属配合物和固体催化剂的优势,其具有反应活性高、反应完成后便于分离和重复使用等特点,已被广泛用于催化各类有机反应中.综述了基于有机聚合物、磁性纳米粒子、碳材料和硅材料等不同类型载体制备的负载型氮杂环卡宾金属配合物催化剂的合成与应用的最新研究进展.     

多咪唑盐合成的N-杂环卡宾金属配合物研究进展

N-杂环卡宾金属配合物具有良好的化学稳定性和催化活性,一直是有机化学研究领域中的热点.咪唑盐作为N-杂环卡宾的前体,其制备容易,结构多样的特点为构建拓扑结构的N-杂环卡宾金属配合物提供了基础.主要针对近年来由环状多咪唑盐、非环状多咪唑盐为配体与金属进行组装,或以咪唑盐与P/N配体与金属共同组装,或经过异腈分布合成法形成的具有特殊柱状、笼状、环状、"分子方"和"分子矩形"等结构的多N-杂环卡宾金属配合物的合成,结构及物理化学性质进行归纳总结,并对其研究前景进行了展望.     

过渡金属N-杂环卡宾配合物合成*

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。     

氮杂环卡宾催化二氧化碳羧化反应的研究进展

二氧化碳是一种来源丰富的可再生资源,科研工作者一直致力于开发能够高效转化二氧化碳的催化体系。氮杂环卡宾在有机化学中是一类非常重要的催化剂,利用氮杂环卡宾-过渡金属配合物催化实现二氧化碳的高效化学转化受到了人们的广泛关注。本文主要根据氮杂环卡宾-过渡金属配合物进行分类,总结归纳了近年来氮杂环卡宾-过渡金属配合物催化二氧化碳羧化反应的研究进展。     

N-杂环卡宾金属配合物在酮硅氢加成反应中的新进展

N-杂环卡宾是一类新型催化剂和配体, 在有机化学中得到了极大的重视. N-杂环卡宾金属配合物的研究在近几年来得到迅速的发展,总结了酮硅氢加成反应中N-杂环卡宾金属配合物催化剂的应用新进展.     

N-杂环卡宾金属配合物的制备及其在碳-碳多重键硅氢加成反应中的新进展

综述了N-杂环卡宾金属配合物的制备方法,并总结了N-杂环卡宾金属配合物在碳-碳硅氢加成反应中的新进展.     

金属氮杂环卡宾配合物的抗肿瘤活性研究进展

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。     

官能团化N,C双齿N-杂环卡宾配合物研究进展

综述了官能团化N,C双齿N-杂环卡宾金属配合物研究的最新进展,着重讨论了这些配合物对各种化学反应的催化性能.     

以联苯为骨架的羟基单咪唑鎓盐的合成

1968年(O)fele Wanzlick首次合成了N-杂环卡宾金属配合物,但是没有引起人们的重视[1-2],直到1991年Arduengo得到了稳定的N-杂环卡宾,才引起化学界的广泛注意与重视[3].随后,Herrmann等人将N-杂环卡宾金属配合物应用在催化领域,如烯烃复分解反应、偶联反应、硅氢化反应、烯烃氢甲酰化反应、炔烃聚合反应、烯烃环丙化反应、芳基硼酸对醛的加成反应、醛的烯丙基化反应等[4].     

水溶性氮杂环卡宾金属配合物的研究进展

氮杂环卡宾(NHCs)金属配合物作为一类重要的催化剂一直是有机合成领域研究的热点。近年来,通过引入水溶性配体而得到的水溶性氮杂环卡宾过渡金属配合物受到广大科研工作者的青睐。本文主要总结了水溶性NHCs的分类、合成及其在C-C偶联反应、复分解反应以及催化加氢反应中的应用,并对水溶性NHCs金属配合物的发展趋势进行了展望。     

N-杂环卡宾的反应及应用

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。     

Replacement of N-heterocyclic carbenes by N-heterocyclic silylenes at a Pd(0) center: Experiment and theory

Via NMR-spectroscopy the relative reactivity of N-heterocyclic silylenes (NHSi) and carbenes (NHC) was studied. Reaction of sterically crowded bis-N-heterocyclic Pd(0) carbene complexes with free N-heterocyclic silylenes led to complete displacement of the N-heterocyclic carbene, which is unexpected knowing that usually a silylene is a weaker bound ligand compared to a carbene. High-level DFT calculations on a small model system and the experimentally used complexes confirm the experimental findings and indicate that steric interactions play an important role in the substitution reaction.     

Heterocyclic carbenes: synthesis and coordination chemistry

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.     

Carbon monoxide-promoted carbene insertion into the aryl substituent of an N-heterocyclic carbene ligand: Buchner reaction in a ruthenium carbene complex

In the presence of carbon monoxide, ruthenium carbenes give a net insertion/ring expansion (Buchner reaction) into one of the aromatic rings of the N-heterocyclic carbene ligand. In alkene metathesis applications, the N-heterocyclic carbene ligand is both robust and typically inert to reactions with the metal-bound carbene. This unique reaction is completely regioselective. The complexes obtained through ring expansion were fully characterized in the solid state using X-ray crystallography and in solution using NMR and IR spectroscopy.     

Removing the sting from the tail: reversible protonation of scorpionate ligands in cobalt(II) tris(carbene)borate complexes

Low-temperature deprotonation of the phenylborane dications, PhB(RIm)3OTf2 (R = tBu, Mes), followed by in situ reaction with CoCl2(thf)1.5, results in the formation of the four-coordinate complexes, kappa3-PhB(RIm)3CoCl, in which the metal is supported by tripodal N-heterocyclic carbene-based ligands. The chloride complexes are exceptionally sensitive to acid and can be reversibly protonated to form the zwitterions kappa2-{PhB(RIm)2(RIm.H)}CoCl2. This unexpected reactivity is attributed to the highly basic nature of the tris(carbene)borate ligands. Reaction of the chloride complexes with methylating reagents results in products that depend on the N-heterocyclic carbene substituent. For R = tBu, the four-coordinate high-spin complex, kappa3-PhB(tBuIm)3CoMe, is formed, while for R = Mes, reduction to a multitude of complexes occurs.     

The aza-Prins Cyclization of Unfunctionalized Olefins Promoted by NHC-Cu Complex and ZrCl4

The aza-Prins cyclization reaction catalyzed by ZrCl₄ and NHC (N-heterocyclic carbene) metal complexes is firstly reported. NHC-copper complexes as promoter and ZrCl₄ as chloride source are utilized under a mild condition, where homoallylic amines and aldehydes are successfully converted to piperidine derivatives in satisfactory yields and diastereoselectivity.     

Facile synthesis of metal N-heterocyclic carbene complexes

A novel electrochemical procedure for the preparation of metal complexes of N-heterocyclic carbenes using imidazolium salts or corresponding silver-NHC complexes as carbene sources and electrolytes, and metal plates as the sacrificial anodes is described. The procedure is simple and good yielding without the use of expensive or air-sensitive reagents.     

A simple, general route to 2-pyridylidene transition metal complexes

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.