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Activation of small molecules by P–N(imido)–P pincer complexes of transition metals

过渡金属 PâN(imido)âP 钳配合物活化小分子

基本信息

批准号：
361827299
负责人：
Dr. Florian Loose
金额：
--
依托单位：
Frick Chemistry Laboratory
依托单位国家：
德国
项目类别：
Research Fellowships
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/361827299?language=en
关键词：
Activation small molecules imido pincer

项目摘要

The catalytic activation of small molecules in combination with the activation and cleavage of element–H bonds is one important challenge in chemistry. Principles of organometallics and coordination chemistry are therefor particularly claimed. In focus of this project is the development of transition metal complexes with novel chelating pincer ligands that generally confer kinetic and thermal stability to the corresponding complexes. A productive metal ligand cooperation and therefor a high reactivity of pincer complexes in element–H activations can be achieved by the incorporation of functionalities that are capable of accepting, storing and donating protons or hydrogen atoms to the position where they are needed. To combine a productive metal ligand cooperation with the trans-labilizing effect of strong donors, P–C(carbene)–P complexes were developed. However, the application of these complexes in catalysis is limited by mg-scale synthesis as well as deactivation processes. This project presents a novel approach to circumvent these limitations by the combination of phosphorous donors and an imido functionality. The application of an imido bond between the ligand and the transition metal center will be achieved by the development of a :N–CH(~PR2)2 ligand system. The changed structure of the chelating backbone will allow an accurate adjustment of the donor properties of the N- and P-functions. These well adjusted ligand systems will be coordinated to early as well as late transition metal centers in this project. The synthetic concept for P–N(imido)–P ligands allows versatile substitution patterns and synthetic pathways. The synthetic approach to such P–N(imido)–P complexes by N–H activation is estimated to allow moderate conditions for the synthesis. In addition to the synthesis of P–N(imido)–P transition metal complexes the characterization of those complexes is in focus of this project. Therefore IR, NMR and EPR spectroscopic methods as well as mass spectrometry and X-ray diffraction will be applied. The insights gained by the spectroscopic and structural characterization of P–N(imido)–P transition metal complexes will be supplemented by reactivity studies. Therefor reactions of P–N(imido)–P transition metal complexes with CO provide a detailed investigation of the nature of the M=N bond by using the CO as trans-arranged indicator ligand. The application of P–N(imido)–P complexes is another central aspect of this project. At first the capability of P–N(imido)–P complexes for bond activations will be investigated by test reactions with amines, terminal alkynes and dihydrogen. These investigations will be used later on for the development of a catalytic application of P–N(imido)–P complexes.

小分子的催化活化与元素-H键的活化和断裂的组合是化学中的一个重要挑战。因此特别要求保护有机金属和配位化学的原理。该项目的重点是开发具有新型螯合钳形配体的过渡金属络合物，这些配体通常赋予相应络合物动力学和热稳定性。通过引入能够接受、储存质子或氢原子并将其提供到需要它们的位置的官能度，可以实现高效的金属配体配合，从而实现钳形配合物在元素H活化中的高反应性。为了将生产性金属配体合作与强供体的反式不稳定作用相结合，开发了P-C（卡宾）-P配合物。然而，这些配合物在催化中的应用受到镁规模合成以及失活过程的限制。该项目提出了一种新的方法来规避这些限制的磷供体和亚氨基功能的组合。通过开发一个：N-CH（~ PR_2）_2配体体系，实现了配体与过渡金属中心之间的亚氨基键的应用。螯合骨架的改变的结构将允许N-和P-官能团的供体性质的精确调节。这些良好调整的配体系统将在本项目中与早过渡金属中心和晚过渡金属中心协调。P-N（亚氨基）-P配体的合成概念允许多种取代模式和合成途径。通过N-H活化合成这种P-N（亚氨基）-P络合物的方法估计允许合成的温和条件。除了合成P-N（亚氨基）-P过渡金属配合物外，这些配合物的表征也是本项目的重点。因此，IR，NMR和EPR光谱方法以及质谱和X射线衍射将被应用。P-N（亚氨基）-P过渡金属配合物的光谱和结构表征所获得的见解将通过反应性研究得到补充。因此，P-N（亚氨基）-P过渡金属配合物与CO的反应提供了一个详细的研究，通过使用CO作为反式排列的指示配体的M=N键的性质。P-N（亚氨基）-P复合物的应用是本项目的另一个中心方面。首先，通过与胺、末端炔和二氢的测试反应来研究P-N（亚氨基）-P络合物的键活化能力。这些研究将用于以后的P-N（亚氨基）-P配合物的催化应用的发展。