Transition Metal Nanoparticles‐Catalyzed Organic Reactions within Porous Organic Cages

Abstract

Transition metal catalysis has played an important role in modern organic chemistry. In order to develop highly efficient and sustainable methodologies, considerable efforts have been devoted to combining the benefits of homogeneous catalysis and heterogeneous catalysis. Porous organic cages (POCs) are a relatively new type of discrete molecules with permanent cavities and good solubilities. These intrinsic properties make POCs expedient catalyst support for the homogenization of heterogeneous transition metal nanoparticles (MNPs). This review mainly focuses on the recent progress of MNPs-catalyzed reductions and coupling reactions within POCs. In most cases, the MNPs@POC complexes have exhibited outstanding reactivity, dispersibility, stability, and reusability. These pioneering contributions have enriched the methodology toolbox for advanced organic synthesis.

CuCo Nanoparticle, Pd(II), and l-Proline Trifunctionalized UiO-67 Catalyst for Three-Step Sequential Asymmetric Reactions

“…The development and application of homo/heterogeneous catalysts have become one of the important tasks in modern organic synthetic chemistry, and the synthesis of almost 90% of industrial chemicals has been succeeded with the aid of catalysts . Meanwhile, only a small number of compounds can be prepared by only one-step reaction and the synthesis of most compounds, especially for pharmaceuticals, agrochemicals, and cosmetics with complex molecular structures, requires multi-step reactions, which are usually involved in elaborate separation, refining procedures, and different kinds of catalysts. − In order to obtain greater economic benefits, researchers strongly hope that the multi-step reaction can be simplified by using a multifunctional catalyst on the basis of ensuring high yield and high selectivity, thereby saving reaction time, reducing the separation and purification process of intermediates, and diminishing the reaction energy consumption and experimental cost. − However, rational spatial distribution of two or more active sites in an individual catalyst faces the following challenges: (1) the introduction of these active sites with different categories (such as organic small molecules, metal nanoparticles, metal complexes and enzymes) and catalytic functions in a single catalyst is usually accompanied by a growing trend toward structural complexity and tedious synthesis steps; − (2) rational spatial distribution of these active sites is critical for independently performing their different catalytic functions, further avoiding deactivation effects between incompatible catalytic groups, such as acid–base and oxidation–reduction sites; (3) under the catalytic conditions of all the sequential steps, such active sites should be chemically stable and maintain their high catalytic activity/selectivity . As a result, the design and development of multifunctional catalysts is important for modern organic transformations but remains a significant challenge.…”