Construction of Covalent Organic Frameworks via Multicomponent Reactions

Abstract

Multicomponent reactions (MCRs) combine at least three reactants to afford the desired product in a highly atomeconomic way and are therefore viewed as efficient one-pot combinatorial synthesis tools allowing one to significantly boost molecular complexity and diversity. Nowadays, MCRs are no longer confined to organic synthesis and have found applications in materials chemistry. In particular, MCRs can be used to prepare covalent organic frameworks (COFs), which are crystalline porous materials assembled from organic monomers and exhibit a broad range of properties and applications. This synthetic approach retains the advantages of small-molecule MCRs, not only strengthening the skeletal robustness of COFs, but also providing additional driving forces for their crystallization, and has been used to prepare a series of robust COFs with diverse applications. The present perspective article provides the general background for MCRs, discusses the types of MCRs employed for COF synthesis to date, and addresses the related critical challenges and future perspectives to inspire the MCR-based design of new robust COFs and promote further progress in this emerging field.

An iodide-containing covalent organic framework for enhanced radiotherapy

“…[54][55][56] In this contribution, we reported a cationic COF with iodide counterions prepared by a three-component in situ reaction. 57 The generated TDI-COF can be a tumor radiosensitizer to enhance colorectal cancer radiotherapy (Fig. 1).…”

Building Blocks and COFs Formed in Concert—Three‐Component Synthesis of Pyrene‐Fused Azaacene Covalent Organic Framework in the Bulk and as Films

“…In recent years, the three-component synthesis has emerged as a powerful methodology for the synthesis of functional COFs. [2,3] Early reports mainly focused on the synthesis of dual-linkage COFs, which incorporate both imine and boronic ester linkages in their final structure. [4] Subsequent studies explored the stabilization of reactive imine bonds.…”

“…For the PSM approach, the framework stability under the employed functionalization conditions and the reaction yield are among the primary considerations. In recent years, the three‐component synthesis has emerged as a powerful methodology for the synthesis of functional COFs [2, 3] . Early reports mainly focused on the synthesis of dual‐linkage COFs, which incorporate both imine and boronic ester linkages in their final structure [4] .…”

Construction of Covalent Organic Frameworks via a Visible-Light-Activated Photocatalytic Multicomponent Reaction

“…12,13 Particularly, these integral benefits make MCRs significantly promising for the construction of stable, crystalline COFs by combining different reversible/irreversible covalent assemblies. Very recently, our group and others have reported a series of robust and crystalline COFs via different types of MCRs, 14 As we know, visible-light-mediated photocatalysis, one of the most promising alternatives to conventional thermosynthesis, has provided abundant opportunities for the discovery of novel organic transformations and has been at the forefront of organic synthesis chemistry in the past decades. 21,22 The rational design and synthesis of COFs via a photocatalysis approach, however, remains rarely explored, 23−25 and the MCR-based photocatalysis for COF synthesis is still unprecedented thus far.…”

“…Multicomponent reactions (MCRs), defined as one-pot reactions that directly combine three or more reactants to form the expected products, generally offer the advantages of simplicity, synthetic efficiency, as well as diversity over traditional chemical reactions. , Particularly, these integral benefits make MCRs significantly promising for the construction of stable, crystalline COFs by combining different reversible/irreversible covalent assemblies. Very recently, our group and others have reported a series of robust and crystalline COFs via different types of MCRs, including Strecker, Povarov, Debus–Radziszewski, thiazole formation, A 3 -coupling, Groebke–Blackburn–Bienaymé, Doebner, Kabachnik–Fields, iminium ion formation, and Claisen–Schmidt–Knoevenagel condensation reactions. − Noteworthy, all the reported MCRs for COF synthesis are thermally driven reactions.…”