Development of Covalent Triazine Frameworks as Heterogeneous Catalytic Supports

Abstract

Covalent triazine frameworks (CTFs) are established as an emerging class of porous organic polymers with remarkable features such as large surface area and permanent porosity, high thermal and chemical stability, and convenient functionalization that promotes great potential in heterogeneous catalysis. In this article, we systematically present the structural design of CTFs as a versatile scaffold to develop heterogeneous catalysts for a variety of chemical reactions. We mainly focus on the functionalization of CTFs, including their use for incorporating and stabilization of nanoparticles and immobilization of molecular complexes onto the frameworks.

Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks

“…3 In COF reactions with only limited reversibility, a low number of conformers might even be essential in leading to crystallinity as exemplified by the examples of COFs based on irreversible reactions (see Section 6.1). The cyclotrimerization of nitriles to form CTFs has a low reversibility, 121 consequently only a few CTFs have been reported to be crystalline, and all are based on low conformer building blocks, 10,[56][57][58] while others based on building blocks with more conformers are amorphous. [122][123][124][125] The structural degrees of freedoms that appear in COFs because of the flexibility of building blocks are largely tuneable due to the wide range of possible structures, while flexibility of the COF linkages, which are limited in number, make additional conformational degrees of freedom sometimes unavoidable.…”

Covalent Triazine Frameworks Obtained from Nitrile Monomers for Sustainable CO2 Catalysis

“…In view of the above, CTFs are generally utilized as an ideal support for homogeneous molecular catalysts and also provide an attractive pathway for the stabilization of metal nanoparticles. [8] Furthermore, they might be used as a promising candidate as precursors of nitrogen-doped porous carbon materials that can be easily obtained after pyrolysis (Scheme 2). [9] In other words, there are four main categories in CTFs as catalysts and support materials: (i) metal-free catalysts; (ii) supports for solid molecular catalysts; (iii) supports for nanoparticulate catalysts; (iv) precursors of N-doped porous carbon materials.…”

Efficient Photocatalytic Oxidation of Aromatic Alcohols over Thiophene‐based Covalent Triazine Frameworks with A Narrow Band Gap

“…[8][9][10][11][12][13][14][15][16][17][18] In recent years, the development of metal-free photocatalysts has attracted great attention among researchers. [9,[19][20][21][22][23] Among them are many classes of porous organic polymers (POPs), including conjugated microporous polymers (CMPs), [24][25][26] covalent organic frameworks (COFs), [11][12][13][14] and porous aromatic frameworks (PAFs) and so forth. Covalent triazine frameworks (CTFs) present a promising material class for photocatalytic applications.…”

“…They hold a triazine unit (aromatic C = N linkage) as a structural element and possess stable covalent bonds. [24][25][26]30] Different approaches for the synthesis of CTFs have been reported including high-temperature ionothermal trimerization, reported by Thomas et al However, the method causes partial carbonization and results in black powders not suitable for photocatalysis. [31][32][33] Besides, CTFs can also be synthesized using trifluoromethanesulfonic acid as a catalyst at room temperature or by microwave heating both avoiding carbonization.…”

“…Covalent triazine frameworks (CTFs) present a promising material class for photocatalytic applications. They hold a triazine unit (aromatic C=N linkage) as a structural element and possess stable covalent bonds [24–26,30] . Different approaches for the synthesis of CTFs have been reported including high‐temperature ionothermal trimerization, reported by Thomas et al .…”