Metal–organic frameworks: 2025 Nobel chemistry explained

Metal–organic frameworks (MOFs) are crystalline materials built from metal ions or clusters (nodes) linked by organic molecules (linkers) into 1D, 2D, or 3D networks with permanent porosity. They are a subclass of coordination networks—coordination polymers extended in multiple dimensions—with the distinguishing feature of retaining internal voids or pores.

Because of their modular design, MOFs are often referred to as “designer sponges” at the atomic scale. Chemists can choose metal nodes and organic linkers to tune pore size, shape, and chemical functionality (this idea is central in “reticular chemistry”).

Key structural features

Nodes and Linkers

Metal nodes (ions or clusters) serve as junction points.

Organic linkers (e.g. carboxylates, imidazolates) bridge between the metal nodes.

The combination of node geometry + linker rigidity dictates topology and pore architecture.

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Porosity and surface area

MOFs can achieve exceptionally high internal surface areas—often exceeding those of zeolites and activated carbons.

A large fraction of their solid volume may be empty space, filled by accessible pores.

One well-known class is zeolitic imidazolate frameworks (ZIFs), where metal ions are linked by imidazolate ligands. These mimic zeolite topology but preserve MOF tunability and stability.

Examples of prototypical MOFs include MOF-5 (a Zn-terephthalate structure), which in early experiments demonstrated very high surface area and gas uptake.

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How Are MOFs Made?

MOFs are synthesized via a range of methods. The purpose is to coax metal nodes and linkers to self-assemble into the desired 3D network.

Common synthetic strategies include:

Hydrothermal / solvothermal synthesis

Microwave-assisted synthesis

Mechanochemical methods (e.g. grinding)

Modulated synthesis (adding modulators to guide growth)

However, practical challenges arise when scaling up. Scientists must also shape MOFs into pellets, coatings, membranes, or monoliths without collapsing the pores.

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Applications of MOFs

MOFs are promising in multiple domains thanks to their tunable pores and chemistry. Some major application areas:

Gas storage & separation

Storage of hydrogen, methane, or other gases.

Selective separation (e.g. CO₂ vs N₂) by designing binding sites.

Carbon capture

Many MOFs are engineered to selectively adsorb CO₂ via open metal sites or functional groups.

The challenge is balancing strong affinity (to capture CO₂) with easy regenerability.

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Atmospheric water harvesting / humidity control

Some MOFs absorb water from low‐humidity air and release it with mild heat.

These have been used in prototype devices for water production in dry climates.

MOFs can serve as heterogeneous catalysts, sensors, or supports for active species.

For electronic applications, conductivity is usually poor; efforts focus on doping, clever linker design, or hybridization.

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Challenges and outlook

Even with the excitement around MOFs, several hurdles remain.

Many MOFs degrade in the presence of water, oxygen, acids, or impurities. For example, in MOF-74, water splitting at metal sites can weaken the framework.

Producing large quantities and converting powders into usable forms (pellets, membranes) without losing porosity is nontrivial.

Some linkers or metal precursors are expensive; reproducibility across batches matters for real devices.

A strong adsorbent may bind a molecule so tightly that it's hard to desorb; balancing adsorption strength vs energy cost is key.

Going forward, integration with computational design (machine learning, high-throughput screening) is pushing MOF discovery further.