Desymmetrized Vertex Design for the Synthesis of Covalent Organic Frameworks with Periodically Heterogeneous Pore Structures

Abstract

Two novel porous 2D covalent organic frameworks (COFs) with periodically heterogeneous pore structures were successfully synthesized through desymmetrized vertex design strategy. Condensation of C(2v) symmetric 5-(4-formylphenyl)isophthalaldehyde or 5-((4-formylphenyl)ethylene)isophthalaldehyde with linear hydrazine linker under the solvothermal or microwave heating conditions yields crystalline 2D COFs, HP-COF-1 and HP-COF-2, with high specific surface areas and dual pore structures. PXRD patterns and computer modeling study, together with pore size distribution analysis confirm that each of the resulting COFs exhibits two distinctively different hexagonal pores. The structures were characterized by FT-IR, solid state (13)C NMR, gas adsorption, SEM, TEM, and theoretical simulations. Such rational design and synthetic strategy provide new possibilities for preparing highly ordered porous polymers with heterogeneous pore structures.

Photoactive and Conducting Covalent Organic Frameworks

“…[4e] In a later work, COFs having periodically heterogeneous pore structures were synthesized by using a desymmetrized vertex design strategy. [11] Recently, a library of about fifty new COFs of symmetric and asymmetric singular-pore structure was reported. This library was accessed through a mixed monomer synthesis approach where subunits of a similar symmetry but different dimensions resulted in pores of different aspect ratios.…”

Simple synthesis of porous melamine-formaldehyde resins by low temperature solvothermal method and its CO2 adsorption properties

“…To mitigate the effect of global warming, many porous materials, such as metal organic frameworks (MOFs) [5][6][7][8][9], porous co-ordination polymers [10,11], porous carbons [12][13][14][15][16], porous organic polymers (POPs) and covalent organic frameworks (COFs) [17][18][19][20], have been investigated for CO 2 storage. In recent years, many amine functionalized or nitrogen-rich porous materials were found to show good CO 2 adsorption properties because of the existence of strong interactions between the nitrogen functionality and CO 2 molecules [21][22][23][24][25][26][27].…”

Precision Construction of 2D Heteropore Covalent Organic Frameworks by a Multiple‐Linking‐Site Strategy

“…However,e ach of these two strategies theoretically can lead to two types of COFs with different topological structures. [38] This drawback prevents unambiguous structural prediction of heteropore COFs from the structures of their building blocks and decreases the control over the construction of heteropore COFs. The previous studies have indeed revealed that, although the combination of tetraphenylethene-based D 2h -symmetrical monomers and linear linkers resulted in dual-pore COFs, [34][35][36][37] the formation of single-pore COFs was also observed when building blocks having the same symmetry but different structures were used.…”