Harnessing the Unquenched Reactivity of Novel Frustrated Lewis Pairs for Transition Metal-Free Hydrogenation Catalysis

利用新型受阻路易斯对的未淬灭反应性进行无过渡金属加氢催化

• 批准号: 246492432
• 负责人: Professor Dr. Jürgen Klankermayer
• 金额: --
• 依托单位: Department of Chemistry and Biochemistry
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/246492432?language=en
• 关键词: Harnessing; Unquenched; Reactivity; Novel; Frustrated

The transition metal free heterolytic cleavage of molecular hydrogen via frustrated Lewis pairs (FLPs) pioneered by Stephan is an innovative concept in sustainable chemistry. It has the potential of replacing expensive, less abundant and toxic precious metals in their classical domain, the catalytic hydrogenation of unsaturated organic species. FLPs are sterically encumbered Lewis acid-base pairs of unquenched reactivity due to their inability to form classical Lewis acid-base complexes. Frequently used FLP catalysts are combinations of bulky phosphines and B(C6F5)3 or related fluorinated boranes. These hydrogenation catalysts are expensive and exhibit poor activities due to the strength of the product-boron bond, which inhibits product liberation. The goal of this collaborative research project is to improve transition-metal free catalytic hydrogenation of olefins, imines and ketones as sustainable alternative to established catalytic systems. In combination with the design of tailored FLP catalysts, recycling strategies will be developed. The investigated catalysts will initially be based on a set of established structural motifs as lead structures for more detailed investigations. Novel combinations of Lewis acids and bases, capable of reversibly cleaving dihydrogen, will be identified by a combined computational/experimental approach. Attractive weak Lewis acids are boronic and boric esters, as these compounds can readily be synthesized from inexpensive starting materials or are commercially available at low cost. Phosphazenes and guanidines will be used as base components. The progress in catalyst development will be amplified with the combination of modular FLP synthesis, detailed catalytic testing and computational investigations on novel catalysts and the underlying catalytic mechanisms. Spectroscopic studies using special high-pressure NMR equipment will provide refined information on the catalytic activity of the FLPs. The ultimate goal of this proposal, however, is the development of highly active, durable and recyclable FLP catalysts able to selectively hydrogenate olefins, imines and ketones under mild conditions.

由Stephan提出的通过阻挫刘易斯对（FLP）进行无过渡金属的氢分子异裂是可持续化学中的一个创新概念。它有可能取代昂贵的，不丰富的和有毒的贵金属在其经典领域，不饱和有机物种的催化氢化。由于FLP不能形成经典的刘易斯酸-碱络合物，因此它们是空间位阻的未淬灭反应性的刘易斯酸-碱对。经常使用的FLP催化剂是大体积膦和B（C6 F5）3或相关氟化硼烷的组合。这些氢化催化剂是昂贵的，并且由于产物-硼键的强度而表现出差的活性，这抑制了产物释放。该合作研究项目的目标是改进烯烃、亚胺和酮的无过渡金属催化加氢，作为现有催化体系的可持续替代品。结合定制FLP催化剂的设计，将制定回收策略。所研究的催化剂最初将基于一组已建立的结构基序作为更详细研究的先导结构。新型组合的刘易斯酸和碱，能够可逆地裂解二氢，将确定由计算/实验相结合的方法。有吸引力的弱刘易斯酸是硼酸和硼酸酯，因为这些化合物可以容易地由廉价的起始材料合成或以低成本商购获得。磷腈和胍将用作基础组分。催化剂开发的进展将与模块化FLP合成，详细的催化测试和计算研究的新型催化剂和潜在的催化机制相结合。使用特殊的高压核磁共振设备的光谱研究将提供有关FLP催化活性的精确信息。然而，该提案的最终目标是开发能够在温和条件下选择性地将烯烃、亚胺和酮加氢的高活性、耐用且可回收的FLP催化剂。