Manganese complex catalysts for hydrogenation and dehydrogenation reactions

用于加氢和脱氢反应的锰络合物催化剂

• 批准号: 398767341
• 负责人: Professor Dr. Rhett Kempe
• 金额: --
• 依托单位: Arbeitsgruppe Anorganische Chemie II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/398767341?language=en
• 关键词: Manganese; complex; catalysts; hydrogenation; dehydrogenation

The sustainable handling of the resources on our planet is a central challenge of humankind. Noble metals are rare, expensive and are used diversely in key technologies. Catalysis is such a key technology. Manganese is the third most abundant transition metal in the earth’s crust and a promising “replacement” for noble metal catalysts in hydrogenation and dehydrogenation reactions. Such a “replacement” becomes especially interesting if new reactivity or selectivity are accessible. In three recent (2016 and 17) preliminary work manuscripts published in Angewandte Chemie, we introduced novel highly active manganese catalysts for important hydrogenation and dehydrogenation reactions. We focus on three aims in the proposal. 1. A better understanding of how PNP-ligand stabilized manganese complexes act in hydrogenation or dehydrogenation reactions and thereof derived novel catalytic applications. 2. The development of novel manganese catalysts based on (chiral) PNN-pincer ligands. 3. The development of novel Mn-catalyzed reactions in which amino alcohols are converted into important classes of compounds. 1. Mechanistic studies of hydrogenation and dehydrogenation catalysis: In the preliminary work, we could show that manganese catalysts are an interesting alternative to noble metal catalysts in the hydrogenation of C=O bonds (Angew. Chem. 2016, paper 1). Right now we don’t know how the catalytic cycle proceeds and how the activation of substrates takes place. We thus propose mechanistic studies, which also permit a more rational catalyst design. The obtained insight should be used for the hydrogenation of imines in the presence of hydrogenation sensitive functional groups. Beside hydrogenation we are interested in mechanistic aspects of the dehydrogenation, especially the role of the base.2. Novel (chiral) catalysts: Progress in manganese based hydrogenation and dehydrogenation catalysis is strongly linked with the development of novel catalysts. Thus, we plan the development of a novel (also chiral) catalyst class. Therefore, a simple and broadly variable ligand synthesis is applied. The novel catalysts are used comparative in a variety of reactions. With regard to enantioselective catalysis, for instance, the hydrogenation of imines is of interest. 3. Novel alcohol re-functionalization reactions: In our preliminary work, we could demonstrate a Mn-Ir analogy in dehydrogenative condensation reaction for the synthesis of aromatic N-heterocyclic compounds (2 x Angew. Chem. 2017, paper 2 and 3). Thus, the development of novel syntheses of heterocycles using manganese catalysts should be possible in the future. Beside the base-tunable Imine-amine synthesis, the development of a novel pyrimidine and imidazole synthesis is proposed. Preliminary work support the feasibility of them.

以可持续方式处理我们星球上的资源是人类的一项核心挑战。贵金属稀有、昂贵，在关键技术中经常使用。催化就是这样一项关键技术。锰是地壳中第三丰富的过渡金属，并且是氢化和脱氢反应中贵金属催化剂的有希望的“替代物”。如果新的反应性或选择性是可获得的，这样的“替换”变得特别有趣。在最近（2016年和2017年）发表在Angewandte Chemie上的三篇初步工作手稿中，我们介绍了用于重要加氢和脱氢反应的新型高活性锰催化剂。我们在提案中着重于三个目标。1.更好地理解PNP-配体稳定的锰配合物在氢化或脱氢反应中的作用及其衍生的新催化应用。2.基于手性PNN钳形配体的新型锰催化剂的开发。3.锰催化的氨基醇转化为重要化合物的新型反应的发展。1.氢化和脱氢催化的机理研究：在初步工作中，我们可以证明锰催化剂是C=O键氢化中贵金属催化剂的有趣替代品（Angew. 2016，论文1）。目前我们还不知道催化循环是如何进行的，以及底物的活化是如何发生的。因此，我们提出了机制的研究，这也允许一个更合理的催化剂设计。所获得的洞察力，应用于氢化的亚胺在氢化敏感的官能团的存在下的氢化。除了氢化反应外，我们还对脱氢反应的机理方面，特别是碱的作用感兴趣.新型（手性）催化剂：锰基加氢和脱氢催化剂的进展与新型催化剂的开发密切相关。因此，我们计划开发一种新型（也是手性）催化剂。因此，应用简单且广泛可变的配体合成。新型催化剂在各种反应中的应用比较。关于对映选择性催化，例如，亚胺的氢化是令人感兴趣的。 3.新的醇再官能化反应：在我们的初步工作中，我们可以证明在芳香族N-杂环化合物的合成的缩合反应中的Mn-Ir类似物（2 x Angew. 2017，论文2和3）。因此，开发新的杂环化合物的合成使用锰催化剂应该是可能的。除了碱基可调的亚胺-胺合成之外，还提出了新型嘧啶和咪唑合成的开发。初步工作支持它们的可行性。