Science

The proof

The proof behind the argument: seven papers, each with the question it asked, what was done, what it reports and what remains open.

MOF-5, shown in idealized geometry. Drag to rotate.

Three routes

Designing frameworks

Construction principles, topology and control of pore architecture: how building blocks of known geometry combine into planned nets, from single-net frameworks to merged, multicomponent structures.

Recognizing and separating molecules

Selectivity, adsorption and membranes: how a pore’s size, shape and chemistry decide which molecules a material admits, holds or excludes, and how that selectivity can be formed into membranes.

Chemistry for energy and environment

Carbon capture and related gas-separation and storage research, including hydrogen and methane storage. Secondary fields, from sensing to catalysis, are in the publication archive.

Terms: MOF: metal–organic framework. Isoreticular: sharing the same underlying net.

A porous framework that holds its shape

Zinc-oxide clusters joined by organic linkers gave a crystalline framework that kept its open structure after the guest molecules were removed. It showed that metal–organic frameworks (MOFs) could be stable, permanently porous solids rather than structures that collapse when emptied. Eddaoudi was then a postdoctoral fellow in Omar Yaghi’s group; the work is an early collaborative foundation of the field.

With Hailian Li, Mohamed Eddaoudi, Michael O’Keeffe and Omar M. Yaghi.

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Same architecture, different pores

Keeping a framework’s underlying net fixed while changing the length and functional groups of its organic linker produced a series of isoreticular MOFs with different pore sizes and chemistry. The series was tested for methane storage. It turned pore architecture into something a chemist could set by design. Eddaoudi is first author, with colleagues from the Yaghi group and Michael O’Keeffe.

With Mohamed Eddaoudi, Jaheon Kim, Nathaniel Rosi, David Vodak, Joseph Wachter, Michael O’Keeffe and Omar M. Yaghi.

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Telling propylene from propane

Propylene and propane are so alike that the chemical industry separates them with energy-intensive processes. Cadiau and colleagues used reticular chemistry to build a fluorinated MOF, KAUST-7 (NbOFFIVE-1-Ni), in which bulkier niobium-oxyfluoride pillars hinder the pyrazine groups lining its channels and fix the size of the pore opening. In laboratory mixed-gas adsorption at atmospheric pressure it took up propylene and excluded propane.

With Amandine Cadiau, Karim Adil, Prashant M. Bhatt, Youssef Belmabkhout and Mohamed Eddaoudi (KAUST).

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From frameworks to membranes

Membrane-based separations can save energy, but the membranes must keep the sieving precision of the crystals inside them. Liu and colleagues, with William Koros’s group, embedded submicrometre fcu-MOF crystals in polymers and showed that the MOF’s contracted pore opening carried through to the membrane, for butane isomers and for CO2 and H2S removal from natural gas.

With Gongping Liu, Valeriya Chernikova, Yang Liu, Kuang Zhang, Youssef Belmabkhout, Osama Shekhah, Chen Zhang, Sunghwan Yi, Mohamed Eddaoudi and William J. Koros.

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Merging nets: a wider design language

Designing structures with several kinds of building unit has lacked suitable blueprint nets. Jiang and colleagues mapped node–net relationships among 53 basic edge-transitive nets, enumerated 53 merged nets and proposed more than 100 multicomponent MOF platforms, then synthesized four classes of materials to test the idea.

With Hao Jiang, Salma Benzaria, Norah Alsadun and colleagues, with Michael O’Keeffe and Mohamed Eddaoudi.

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Editing a crystal without losing it

Some frameworks need a temporary extra ligand, a centring structure-directing agent (cSDA), in order to form at all. Sapianik and colleagues report removing or substituting these agents after synthesis while each crystal stays a single crystal, which can transform the topology and raise porosity: pore volumes of up to 3.6 cm³ g⁻¹ for Cr-MOFs.

With Aleksander Sapianik, Marina Barsukova, Aleksander Shkurenko, Mickaele Bonneau, Prashant M. Bhatt, Osama Shekhah, Vincent Guillerm and Mohamed Eddaoudi.

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Making MOF membranes at industrial scale

A team led by Sheng Zhou at HKUST (Guangzhou), a former KAUST doctoral student of Eddaoudi’s, reports a membrane that is more than 90 percent MOF yet can be manufactured with industrial solution-processing. In the reported work the team produced continuous 20-metre membrane rolls and, in testing, polymer-grade propylene in a single separation step with stable operation over 150 days.

With A team led by Sheng Zhou (HKUST Guangzhou), with Shizheng Song, Guillaume Maurin, Yu Han, Haihui Wang, Mohamed Eddaoudi and colleagues. Eddaoudi is a corresponding author.

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