Three-Dimensional Covalent Organic Frameworks with Dual Linkages for Bifunctional Cascade Catalysis

Abstract

Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with broad potential applications. So far, the availability of three-dimensional (3D) COFs is limited and more importantly only one type of covalent bond has been successful used for 3D COF materials. Here, we report a new synthetic strategy based on dual linkages that leads to 3D COFs. The obtained 3D COFs show high specific surface areas and large gas uptake capacities, which makes them the top COF material for gas uptake. Furthermore, we demonstrate that the new 3D COFs comprise both acidic and basic sites, and act as excellent bifunctional catalysts for one-pot cascade reactions. The new synthetic strategy provides not only a general and versatile approach to synthesize 3D COFs with sophisticated structures but also expands the potential applications of this promising class of porous materials.

Opportunities of Covalent Organic Frameworks for Advanced Applications

“…[53] Reacting tetrahedral TAA with 4-formylphenylboronic acid or 2-fluoro-4-formylphenylboronic acid, afforded two 3D bifunctional COFs named as DLCOF-1 and DLCOF-2, respectively. Qiu and co-workers demonstrated the construction of two new 3D COFs with both acidic and basic sites, resulted from the linkages boroxine and imine, respectively, and their application in acid/base bifunctional catalysis.…”

Defective 2D Covalent Organic Frameworks for Postfunctionalization

“…Their tunable structures and pore sizes, high surface area values, and good thermal/chemical stabilities make them good candidates in various applications . Since the first COF was reported by Yaghi's group in 2005, numerous 2D or 3D COFs have been achieved by utilizing different kinds of building blocks via dynamic covalent chemistry principle. As reported, COFs are designed to obtain an ideal crystal as perfect as possible, which are well‐aligned arrangements and structural regularities by connected the building blocks.…”

Imidazolium‐Salt‐Functionalized Covalent Organic Frameworks for Highly Efficient Catalysis of CO2 Conversion

“…[7][8][9] Various catalysts have been investigated for the cycloaddition reaction. [12][13][14] Covalent organic frameworks (COFs) [15][16][17] are anothern ovel class of crystalline porous materials with wide applicationsi n molecule storage and separation, [18][19][20] catalysis, [21][22][23][24][25][26] energy storage, and others. [10,11] For example, metal-organic frameworks (MOFs) have served as excellent heterogeneousc atalysts for this reaction.…”