N-heterocyclic carbenes incorporated in porous networks

N-杂环卡宾纳入多孔网络

• 批准号: 102827635
• 负责人: Professor Dr. Arne Thomas
• 金额: --
• 依托单位: Equipe Architectures Moléculaires et Matériaux Nanostructurés (AM2N) ENSCM
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/102827635?language=en
• 关键词: heterocyclic; carbenes; incorporated; porous; networks

The elaboration and the design of re-usable catalyst systems is a key issue in green process engineering. The concept of heterogeneous catalysis often allows to achieve recyclable catalysts, but factors such as metal leaching, catalyst poisoning and catalyst deterioration often limit the applicability of this approach. The CAPONE project focuses on new concepts towards the immobilization of Nheterocyclic carbenes. Metallic NHC species recently appeared as a particularly versatile new class of catalysts for numerous reactions under extremely mild conditions. The immobilisation of such NHC species would allow to combine high catalytic activity on one side and recyclability on the other side. Using bifunctional carbene precursors, porous networks will be synthesized by a bottom-up approach featuring the NHC as inherent part of the porous material instead of just grafting it from a pre-formed support. We will focus on the elaboration of two types of porous materials bearing NHC species: • hydrophilic periodic mesoporous organosilicas (PMOs) and • hydrophobic organic polymer networks For applications in heterogeneous catalysis, the adjustment of the polarity of the reaction medium and the heterogeneous catalyst can be desirable. For this reason, the use of PMOs may be interesting in aqueous media, whereas organic polymer network are more useful when organic solvents are employed. We believe that these materials have great potential as heterogeneous catalyst systems for the following reasons: i) high porosity of the used supports that ensures accessibility of immobilized NHC species, ii) Chemical and morphological stability of the catalyst should be strongly enhanced due to the dense incorporation of the NHC into the porous network by the twofold-bonding.

可重复使用的催化剂系统的精心设计和设计是绿色过程工程的关键问题。多相催化的概念通常允许实现可回收的催化剂，但金属浸出、催化剂中毒和催化剂劣化等因素往往限制了这种方法的适用性。 CAPONE 项目重点关注非杂环卡宾固定化的新概念。金属 NHC 物质最近作为一种特别通用的新型催化剂出现，可在极其温和的条件下进行多种反应。这种 NHC 物质的固定化可以将一方面的高催化活性与另一方面的可回收性结合起来。使用双功能卡宾前体，通过自下而上的方法合成多孔网络，其中 NHC 作为多孔材料的固有部分，而不是仅仅从预成型的支撑物上接枝。我们将重点研究两类带有NHC物质的多孔材料： • 亲水性周期性介孔有机硅（PMO）和 • 疏水性有机聚合物网络 对于多相催化应用，需要调整反应介质和多相催化剂的极性。因此，在水介质中使用 PMO 可能会更有趣，而在使用有机溶剂时有机聚合物网络更有用。我们认为这些材料作为非均相催化剂系统具有巨大的潜力，原因如下：i）所用载体的高孔隙率确保了固定化NHC物质的可及性，ii）由于NHC通过双重键合紧密结合到多孔网络中，催化剂的化学和形态稳定性应得到极大增强。