Themed collection Covalent organic frameworks

The last 10 years have seen an explosion of interest in crystalline porous frameworks, in particular metal–organic frameworks (MOFs) and porous coordination polymers (PCPs).

In this highlight, we review the recent progress of utilizing Schiff-base chemistry to construct porous discrete organic molecular cages and polymer networks. Their applications in gas adsorption and catalysis were also discussed.

Three novel crystalline forms of cucurbit[6]uril (CB[6], 1) have been identified by fine control of the mixing process of a hydrochloride solution of CB[6] with ethanol.

A transesterification process to synthesize a mesoporous functionalized COF starting from a benzothiadiazole bis-pinacolboronate in only 40 min.

Synthesis of a new calixarene building block facilitates elimination of crystallographic disorder in the corresponding self-assembled triply helical nanotube motif (shown), as well as the interstitial regions between neighbouring assemblies.

A mesoporous triptycene-derived 2D COF has been prepared and fully characterized. The use of triptycene leads to a high surface area (SA_Lang = 3832 m² g⁻¹), accessible boron-sites, and high gas uptake under low pressure settings.

Crystals of a series of solvated cadmium-based metallocycles undergo single-crystal to single-crystal transformations (SCTSCT) upon desolvation to yield an empty apohost; these transiently porous crystals then allow the diffusion of bulky solvent molecules.

Molecular crystals of dipeptides containing open channels can selectively absorb CO₂ over N₂ and CH₄, as shown by experimental and simulated isotherms.

Methyl-, hydroxymethyl-, and phthalimidomethyl-functionalized versions of the porous organic polymer PAF-1 have been obtained through de novo synthesis.

A new C₃-symmetric vertex unit forms a class of star-shaped COFs with high surface area and tunable 1D channel apertures.

A series of substituted 1,4-benzenediboronic acids (BDBA) was synthesized and their thermal properties investigated.

In-situ coordination chemistry allows the control over cobalt cation oxidation state, axial ligand and crystal stability within phthalocyanine nanoporous crystals.

A scheme to predict as yet unknown, hypothetical covalent organic frameworks (COFs) from scratch by screening the possible space of supramolecular isomers is presented.

A new polymorph of azacalix[5]arene pentamethyl ether has been prepared. A comparative study demonstrated that the solid–gas sorption behavior of two polymorphic forms was controlled by the crystal architecture.

In this work we determined the transport diffusivities of CO₂, CH₄, N₂, O₂, and Ar in Leu–Ser dipeptide crystals.