节点文献

Ⅰ钳式镍配合物的合成及性质反应研究 Ⅱ有机氟化物的合成新方法研究

ⅠSynthesis of Pincer Nickel Complexes and Their applications in catalysisⅡSimple Method for the Synthesis of Organofluorine Compounds

【作者】 孙运强

【导师】 李晓燕; 孙宏建;

【作者基本信息】 山东大学 , 有机化学, 2014, 博士

【摘要】 本论文共分为两部分:第一部分是关于钳式配合物的合成及其性质研究的工作。自从钳式配合物在上世纪70年代被Shaw和van Koten报道后,由于其高稳定性.活性以及可调节性,已经得到了深入的发展,并且在有机合成、催化、传感器以及超分子化学等领域得到了广泛的应用。钳式配体可以被简写为[EYE]型,其中Y代表了中心电子供体(Y=C,N等),E代表了像胺(-NR2)、膦(-PR2)、亚磷酸(-P(OR)2).醚(-OR)、硫醚(-SR)、硒醚(-SeR)和N-杂环卡宾(的NHCs))等电子供体。根据边臂上两个电子供体原子的种类可以将钳式配合物分为由两个相同的给体原子[EYE]对称性的钳式配合物以及由两个不同的给体原子构成的[EYE’]非对称性的钳式配体,他们各具特色。对于[EYE]对称性的钳式配合物,它的最大优点是合成简单并且结构容易调节等特性,因此得到了非常广泛的研究。相比来说,研究发现,对于由两个不同的给体原子构成的[EYE’]非对称性的钳式配体,在两个不同给体原子的协同作用下,不对称的钳式配合物可能具有非常独特的特性并因此具有更高的活性,因此[EYE’]非对称性的钳式配合物也吸引了越来越多科研人员的兴趣。然而由于相对较复杂的合成过程,对[EYE’]非对称性的钳式配合物的报道远远少于[EYE]对称性的钳式配合物。另外,在钳式配合物的研究中,钯、钌、铑和铱等4d和5d的贵金属催化剂最引人关注,但是他们的缺点很明显,价格昂贵并且对环境污染严重。3d的镍金属催化剂与它们相比,优势在于价格更便宜、毒性更低、更加环境友好。在本论文中,我们分别依据文献已知的方法合成了[PCP]对称性钳式镍配合物,并且合成了另一种新型的以NHC-Amine作为锚定基团的[CNN]非对称性钳式镍配合物。以氯代芳烃与格氏试剂的Kumada偶联反应中考察了他们的活性,发现两种配合物在温和的反应条件下,对催化氯代芳烃与格氏试剂的Kumada偶联反应中显示了很好了活性,并且底物的普适性也很好,在用不同的氯代芳烃和不同的格氏试剂进行反应时,均取得了不错的分离产率。该催化剂不但对单氯取代的芳烃与格氏试剂进行Kumada反应时有较好的效果,而且对于二氯取代的芳烃与格氏试剂进行的双偶联反应,同样显示了很好的催化效果。第二部分是关于在无催化剂条件下通过全氟芳烃与格氏试剂反应合成多氟芳香化合物的工作。有机氟化物在农药、医药等生理活性化合物的中间体中具有很广泛的应用,但是含氟有机化合物在自然界中非常少见。到目前为止,天然产物中只发现了几十种含有C-F键的化合物。因此向有机分子中选择性的引入氟原子或含氟基团以合成含氟有机物一直是有机化学家非常感兴趣的研究领域。在这部分工作中我们发现了一种制备多氟芳香化合物的简单方法。在无过渡金属催化剂存在的条件下,室温下实现了全氟芳香化合物与格氏试剂的交叉偶联反应。虽然在上世纪五六十年代曾经有人报道过类似的反应,但是由于产率以及选择性较低的原因,没能引起足够的重视。在本文中,我们发现全氟芳香化合物与格氏试剂反应,在比较温和的条件下,能以较高的产率得到多氟芳香化合物。我们对这个反应的机理进行了研究,提出了一种通过四元环过渡态的反应机理,并且通过理论计算进行了验证。需要特别指出的是,全氟芳烃不仅可以与芳基格氏试剂反应,而且还能与烷基格氏试剂反应,得到中等至良好的产率。

【Abstract】 The thesis is divided into two parts::The first part is concering about the synthesis of pincer complexes and their application. Since reported by Shaw and van Koten in the1970s, due to their high stability, activity and adjustability, pincer complexes have been well developed, and been widely used in organic synthesis, catalysis, sensors, and supramolecular chemistry fields. Pincer ligand may be abbreviated as [EYE], wherein Y represents a donor center (Y=C, N, etc.), E represents the image amine (-NR2), phosphine (-PR2), phosphorous acid (-P(OR)2), ether (-OR), thioether (-SR), selenides (-SeR), N-heterocyclic arbine (the NHCs)) and so on.According to the kinds of arm donor atoms, pincer complexes can be divided into two types, symmetric pincer complexes have two identical donor atoms abbreviated as [EYE] and unsymmetric pincer complexes have two different donor atoms abbreviated as [EYE’]. For symmetric pincer [EYE] complexes, their biggest advantage was their very simple synthesis and easy modification to the structure, so they have been very extensively studied. In contrast, the study found that for the unsymmetric pincer [EYE’] complexes, the cooperation effect of two different donor atoms may have very unique characteristics and therefore has higher activity, and therefore [EYE’] unsymmetric type of pincer complexes have attracted the interest of more and more researchers. However, due to the relatively complex synthesis, reports of [EYE’] unsymmetric type of pincer complexes were far less than [EYE] symmetrical type of pincer complexes.In the study of the pincer complexes, palladium, ruthenium, rhodium, ruthenium and other noble metal catalyst were most studied, but their shortcomings are obvious because of expensive and serious environmental pollution. Compared to them, nickel is cheaper, less toxic and more environmentally friendly.In this paper, we synthesized the [PCP] symmetric pincer nickel complexes based on known methods in the literature and another new [CNN] unsymmetric type pincer nickel complexes. Kumada coupling of chlorinated aromatics with Grignard reagents was chosen to investigated their activities, it was found that under mild reaction conditions the two types of complexes both showed good reactivity, and the universality of the substrate is also very good. It is worth mentioning that for the double couplings of aryl dichlorides, pincer nickel complexes also showed excellent catalytic activities.The second part was about transition-metal-free synthesis of Fluorinated Arenes from perfluorinated arenes coupled with Grignard Reagents. Fluorinated compounds have great application in pesticide intermediates, medicine and other physiologically active compounds, however, fluorinated organic compounds in nature are very rare, so far only dozens of compounds found in natural contain C-F bond. Therefore, selectively introducing fluorine atom or fluorine-containing group into the organic molecules has attracted many organic chemist’s interest.In this part of the work we have found a simple way to get fluoride aromatic compounds, without the presence of transition metal catalyst, Synthesis of Fluorinated arenes from perfluorinated arenes coupled with Grignard Reagents. Though in the1950s and1960s there was once reported the similar reactions, but because low yields and low selectivity, few attention has concering about this discovery. In this article, we found that perfluorinated aromatic compounds react with Grignard reagents under relatively mild conditions, and higher yields can be obtained for polyfluorinated aromatic compounds.We studied the mechanism of this reaction and proposed a four-membered ring transition state, and supported by theoretical calculations. Special noted that perfluorinated aromatic compounds not only react with aryl Grignard reagent, but also the reaction with alkyl Grignard reagent give moderate to good yields.

  • 【网络出版投稿人】 山东大学
  • 【网络出版年期】2014年 10期
节点文献中: