Reticular Synthesis of Microporous and Mesoporous 2D Covalent Organic Frameworks

Abstract

Three new crystalline microporous and mesoporous 2D covalent organic frameworks termed COF-6, -8, and -10 from boronic acid building blocks and 2,3,6,7,10,11-hexahydroxytriphenylene have been synthesized and structurally characterized. These materials constructed of C2O2B rings form eclipsed layered structures with pore sizes ranging from 6.4 to 34.1 Å and are found to have high thermal stability, low density, and high porosity as indicated by the surface areas of 980, 1400, and 2080 m2 g-1 for COF-6, -8, and -10, respectively. The control of pore size and structure demonstrates the effectiveness of reticular chemistry methods toward materials design.

Controlling the Crystallization of Porous Organic Cages: Molecular Analogs of Isoreticular Frameworks Using Shape-Specific Directing Solvents

“…2), which dominates the lattice energy. A conceptual analogy can be drawn with isoreticular MOFs 45 and COFs, 7,8 but here the non-covalent dioxane-cage interaction takes the role of directional intermolecular bonding in enforcing isostructural crystal packing in a series of structurally related materials.…”

“…24 Hence, each chemical modification results in a new crystal packing and a new pore structure. This is quite different from isoreticular MOFs [43][44][45] and COFs, 7,8 where families of isostructural porous materials are formed with a range of organic linkers, retaining the same framework topology in each case. For isoreticular frameworks, this is achieved by directional interactions that dominate the crystal lattice energy.…”

“…1 This has been achieved in crystalline zeolites 2 and in other extended networks and frameworks, such as metalorganic frameworks (MOFs), [3][4][5][6] covalent organic frameworks (COFs), 7,8 and organic polymer networks. [9][10][11] There is also growing interest in porous materials composed of discrete organic [12][13][14][15][16][17][18][19] or metal-organic [20][21][22][23] molecules.…”

Polymers of Intrinsic Microporosity

“…In particular, there has been a rapid development of microporous materials that are prepared using organic components rather than the inorganic building blocks of conventional microporous materials such as the zeolites. These materials include the much studied crystalline metal organic frameworks (MOFs) [2][3][4][5] and purely organic but structurally similar covalent organic frameworks (COFs) [6][7][8]. In addition, there has been intense activity in the synthesis and study of amorphous polymer networks with a wide variety of structures such as the hyperCrosslinked polymers (HCPs) [9][10][11][12] and microporous conjugated polymers (MCPs) [13][14][15][16][17][18].…”

First-Principles Investigation of Li⁺-Doped Conjugated Microporous Polymer as a Potential Hydrogen Storage Medium

“…While considerable challenges exist in hydrogen economy, enormous efforts have been focused on developing viable hydrogen storage materials [1]. Previous studies have been devoted to complex light metal hydrides [2] as well as carbon [3][4][5][6][7][8] or BN [9,10] based nanostructures, metal-organic frameworks (MOF) [11][12][13][14][15][16], covalent organic frameworks (COF) [17][18][19][20][21], zeolites [22][23][24], and even organic chemical hydrides [25][26][27][28]. Although many of them exhibit interesting characteristics, the problems still remain due to that they all have poor thermodynamics or kinetics, and actually none in experiment yet meet the new 2017 US Department of Energy target of 5.5 wt% reversible hydrogen storage at ambient condition.…”