Rational Synthesis of a Hierarchical Supramolecular Porous Material Created via Self-Assembly of Metal–Organic Framework Nanosheets

Abstract

Hierarchically porous materials with high stability and tailorable pore characters have potential for mass transfer applications, including bulky molecule capture and separation, heterogeneous catalysis, and drug delivery. The scope of functionalities can be notably broadened by employing metal−organic framework (MOF) sheets with tunable thickness as giant molecular building blocks for self-assembly into hierarchical supramolecular porous coordination materials. However, synthesizing MOF sheets with controllable bulkiness has proved challenging for scientists. We present a rational yet unprecedented bottom-up strategy to prepare a novel twodimensional MOF sheet [Zn(BPDI)(Py) 2 ] (BPDI = N,N′-bis(glycinyl)pyromellitic diimide; Py = pyridine) with unusual and highly desired tunable thickness. These sheets self-organize into a unique three-dimensional supramolecular coordination material (NEU-1) with tailorable porosity. To assess its technological relevance, NEU-1c is tested as a support of amine sorbent for CO 2 capture. Multichannel porous NEU-1c solves the conventional trade-off suffered by supported amine carbon dioxide adsorbents between increasing amine content and decreasing access to amine sites. Our synthesis process opens the door to novel MOF nanosheets and unique hierarchical supramolecular porous materials with tailorable porosity.

Self-assembly of colloidal metal–organic framework (MOF) particles

“…90 Moreover, self-assembled MOF particles may benefit the countless applications for which MOFs offer promise, such as adsorption, separation, catalysis, and drug delivery. 100–109…”

“…90 Moreover, selfassembled MOF particles may benefit the countless applications for which MOFs offer promise, such as adsorption, separation, catalysis, and drug delivery. [100][101][102][103][104][105][106][107][108][109] The practical exploitation of MOF-based superstructures is limited by their chemical stability and susceptibility to mechanical stress. The stability of MOF-based superstructures has not yet been extensively studied; therefore, the current data set is insufficient.…”

Synthetic and analytical considerations for the preparation of amorphous metal–organic frameworks

“…In the mixed-metal series of ‘NEU’ MOFs, a liquid–liquid interface synthesis was employed, with limited change in synthetic conditions, resulting in the formation of a s MOFs with a range of metal salts and linkers. 61,135,136,143 This was achieved through controlled diffusion of reagents through an intermediate solvent, encouraging ligand-to-metal electron transfer. This is supported by the effective synthesis of A x B y C z -NiFe aMOFs, defined in Table 1, using a variety of terephthalic-acid based linkers without requiring changes to the synthetic conditions.…”

Structure and properties of metal–organic frameworks modulated by sulfate ions

“…[18][19][20] Three-dimensional microporous MOF materials have been highly sought after by researchers due to their larger porosity and surface area, which make them more suitable for applications in catalysis, [21][22][23] loading, 24,25 and adsorption. 7,26 In addition, their high porosity makes it easier to functionalize them and optimize their properties. However, accurately designing and obtaining 3D microporous MOFs has been a challenge for many researchers.…”