Vinylene-Bridged Two-Dimensional Covalent Organic Frameworks via Knoevenagel Condensation of Tricyanomesitylene

Abstract

Vinylene-bridged covalent organic frameworks (COFs) have shown great potential for advanced applications because of their high chemical stability and intriguing semiconducting properties. Exploring new functional monomers available for the reticulation of vinylene-bridged COFs and establishing effective reaction conditions are extremely desired for enlarging the realm of this kind of material. In this work, a series of vinylene-bridged two-dimensional (2D) COFs are synthesized by Knoevenagel condensation of tricyanomesitylene with ditopic or tritopic aromatic aldehydes. With use of appropriate secondary amines as catalysts, high-crystalline vinylene-bridged COFs were achieved, exhibiting long-range ordered structures, well-defined nanochannels, high surface areas (up to 1231 m 2 g −1 ), and excellent photophysical properties. Under a low loading amount and short reaction time, they enable aerobic photocatalytic transformation of arylboronic acids to phenols with high efficiency and excellent recyclability. This work demonstrates a new functional monomer, tricyanomesitylene, feasible for the general synthesis of vinylene-bridged COFs with potential application in photocatalytic organic transformation, which instigates further research on such kind of material.

Three-Dimensional Triptycene-Based Covalent Organic Frameworks with ceq or acs Topology

“…Covalent organic frameworks (COFs), an emerging family of crystalline porous polymers, are assembled from organic reactants by reversible covalent bonds. [1][2][3][4][5] Due to their high surface area, modular nature, and good thermal/chemical stability, COF materials have attracted considerable attention in gas storage/separation, [6][7][8][9] organic electronics, [10][11][12][13][14] heterogeneous catalysis, [15][16][17][18][19][20] and some other fields. [21][22][23][24][25] Over the past decade, most of reports were focused on conjugated two-dimensional (2D) sheets, in which the abundant building blocks allowed to establish well developed synthetic strategies.…”

All sp2 carbon covalent organic frameworks

“…Topology diagram: the scheme in which monomers are designed to possess specific geometries so that their connections enable the growth of extended polygonal architectures. hexagonal frameworks (Figure 1A) [13,18,21,[29][30][31][32][33][34][35]. The [C 4 + C 2 ] combination with a C 4 -symmetric knot and C 2 -symmetric linker generates tetragonal frameworks so that the polymer backbones extend along both the x and y directions (Figure 1B) [20,36].…”

“…•− ( [35] and the supplemental information online). Por-sp 2 c-COF bearing a porphyrin knot (Figure 5J) has been shown to serve as a photocatalyst promoting photoinduced aerobic oxidation of secondary amines to imines ( [20,36] and the supplemental information online).…”

Covalent Organic Frameworks as Electrode Materials for Rechargeable Batteries

“…Consequently, interest in more chemically robust frameworks led to the development of more stable linkages including azines, 23,24 oxazoles, [25][26][27] and olefins ( Figure 2). [28][29][30] By leveraging the design principles mentioned above, it has become possible to obtain a rich variety of twodimensional (2D) and three-dimensional (3D) COF architectures through careful selection of π-electron-rich monomers with different symmetries (Figure 3). Indeed, it has allowed molecular-scale, topological precision while simultaneously providing strategies for synthesis of functional materials by leveraging structure-function relationships.…”