Facile Synthesis of a Highly Crystalline, Covalently Linked Porous Boronate Network

Abstract

A covalent organic framework (COF-18Å) based on poly(boronate ester)s has been successfully synthesized through a facile dehydration process in 85−95% isolated yield. Spectroscopic characterization confirms formation of the intended ester linkages as the key structural motif forming infinite 2D hexagonally porous sheets. Powder X-ray diffraction studies were used to determine the stacking orientation between the ester-linked sheets, such that atoms in adjacent layers lie directly over each other, resulting in a hexagonal array of 1D, 18 Å pores. COF-18Å exhibits rigid, thermally stable (to 500 °C) pores with high surface area (1260 m2/g) and a micropore volume of 0.29 cm3/g.

Self-templated chemically stable hollow spherical covalent organic framework

“…The hollow spherical COF (DhaTab), reported in this paper, consists of a macroporous inner cavity (pore width 0.5-2 mm) wrapped up by the mesoporous COF shell (width 20-40 nm). It is noteworthy that the application of COFs is still mostly limited to the storage of gas molecules, since most of the COFs synthesized are microporous in nature and their pores are not sizable enough to hold larger guests, such as enzymes [38][39][40] . While examples of mesoporous boronic acid-based COFs have been reported in the literature 41,42 their chemical instability prevents the usage of these materials for the storage of drugs and enzymes 43,44 .…”

Pore surface engineering in covalent organic frameworks

“…The pore surface forms a microscopic interface with gas or guest molecules, and is an important characteristic that determines the macroscopic nature of these materials in applications such as gas adsorption, molecular separation, catalysis and energy storage. Among these materials, covalent organic frameworks (COFs) are a class of porous materials that feature low-weight elements and strong covalent linkages of their components, and they exhibit high flexibility in their molecular design, which allows the atomically precise integration of their building blocks into porous structures [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] . COFs can be constructed by the reticular design of their components, which, upon undergoing condensation reactions, form a porous skeleton with a precise pore size and specific pore geometry.…”

Recent Progress in the Fabrication of Low Dimensional Nanostructures via Surface-Assisted Transforming and Coupling

“…Therefore, ignoring the long-range ordered characteristics of the polymers, the topological diversity of nanostructure can be used to tune the electronic property of SCOF. This general design principle of organic materials is popular in supramolecular monolayers [47,48], isoreticular metal organic frameworks (MOF) [49], and 2D metal coordinated networks [50] and has also been exploited successfully for bulk crystals of various diboronic acid-derived COFs [51][52][53].…”