Photoredox Catalysis in Aqueous Media by Well-defined Micellar Nanoreactors

明确的胶束纳米反应器在水介质中的光氧化还原催化

• 批准号: 506620588
• 负责人: Dr. Afshin Nabiyan, Ph.D.
• 金额: --
• 依托单位: Institut für Chemie
• 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/506620588?language=en
• 关键词: Photoredox; Catalysis; Aqueous; Media; Well

Despite many chemical reactants often reveal a low aqueous solubility in water, nature could perform all kinds of their chemical transformations reactions in water. Recently, catalysis by organic photoredox materials has emerged as a new and powerful strategy in synthetic organic chemistry to perform a wide variety of transformations. However, performance and extending the substrate scope of them in the aqueous phase is an extremely difficult task. Consequently, the main focus of this project is to construct organophotoredox active micelles that can facilitate catalysis in water under visible light irradiation. Especially the ability to perform organic reactions in aqueous media together with effective recycling strategies for catalysts will be the aim of this project to represent a keystone towards sustainable and green chemistry. Hereby, acridinium molecules as a promising candidate for organophotoredox catalyst will be loaded into the micellar core of polypeptoid block copolymer micelles. Poly(N-substituted glycines) (i.e., polypeptoids) are biocompatible, synthetically accessible, chemically and enzymatically stable, chemically diverse, and structurally controllable. Defined side-chain modification of them and choosing the sequence of the monomers in their copolymers allows the straightforward engineering and determination of the solution properties. Thereby, the catalytic active micellar system of them will be tuned and examined for direct C−H cyanation of aromatic compounds, the nucleophilic substitution of unactivated fluoroarenes, and ipso amination of alkoxyarenes. Noticeably, the scaffold of the micellar system will be reinforced by covalent crosslinking of the core or shell which leads to the high stability of the overall system against external stimuli and harsh reaction conditions such as pH, temperature, and additives. However, these approaches also will provide us several other benefits including adjusting the interaction in the core, better protection of photoredox units from deactivation and leaching, recovery of the catalysts, and presumably improving the transportation and diffusion of the reactants between hydrophobic and hydrophilic domains. The project will also address several fundamental barriers in organic photoredox reactions in the water regarding catalytic activity, efficiency, and stability. In more detail, increasing the lifetime of photoredox reactions, protecting active sites from decomposition, reduces the time of reactions, and preventing the photoredox catalysts from aggregation and precipitation.

尽管许多化学反应物在水中的溶解度很低，但在自然界中，它们可以在水中进行各种化学转化反应。近年来，有机光氧化还原材料的催化作用已成为有机合成化学中一种新的、强有力的策略，可以进行各种各样的转化。然而，它们在水相中的性能和扩展底物范围是一项极其困难的任务。因此，本计画的主要焦点是建构有机光氧化还原活性胶团，使其在可见光照射下，能促进水中的催化作用。特别是在水介质中进行有机反应的能力以及有效的催化剂回收策略将是该项目的目标，代表了可持续和绿色化学的基石。因此，吖啶分子作为一个有前途的候选人的有机光氧化还原催化剂将被装载到胶束的多肽类嵌段共聚物胶束的胶束核心。聚（N-取代的甘氨酸）（即，类多肽）是生物相容的、可合成的、化学和酶稳定的、化学多样的和结构可控的。它们的定义的侧链改性和选择其共聚物中的单体序列允许简单的工程和溶液性质的测定。因此，它们的催化活性胶束系统将被调整和检查用于芳香族化合物的直接C-H氰化，未活化的氟代芳烃的亲核取代，以及烷氧基芳烃的ipso胺化。值得注意的是，胶束系统的支架将通过核或壳的共价交联而增强，这导致整个系统对外部刺激和苛刻的反应条件如pH、温度和添加剂的高稳定性。然而，这些方法也将为我们提供几个其他的好处，包括调整在核心中的相互作用，更好地保护光氧化还原单元从失活和浸出，回收的催化剂，并可能改善疏水和亲水域之间的反应物的运输和扩散。该项目还将解决水中有机光氧化还原反应中有关催化活性，效率和稳定性的几个基本障碍。更详细地，增加光氧化还原反应的寿命，保护活性位点免于分解，减少反应时间，并防止光氧化还原催化剂聚集和沉淀。