Moisés Pinto,  a professor at Técnico and researcher at Centro de Recursos Naturais e Ambiente (CERENA), and Vânia André, a researcher at Centro de Química Estrutural (CQE), comment on the awarding of the Nobel Prize in Chemistry 2025, given to Susumu Kitagawa, Richard Robson and Omar Yaghi for their pioneering work on Metal-Organic Frameworks (MOFs), a new class of materials “with promising applications”.

How do you explain the importance of the work recognised by the Nobel Prize in Chemistry 2025? How does it justify the Nobel Prize?

Moisés Pinto (MP) – This year, the Swedish Academy awarded the Nobel Prize in Chemistry to researchers Susumu Kitagawa, Richard Robson, and Omar Yaghi for their pioneering work on metal-organic frameworks (MOFs). In the late 1980s and early 1990s, Richard Robson reported the potential for creating frameworks consisting of centres with metal ions coordinated with specific organic molecules (ligands) arranged in a regular pattern. A few years later, almost simultaneously, Susumu Kitagawa and Omar Yaghi demonstrated that these frameworks could be constructed to form three-dimensional structures with regular internal porosity at the molecular scale, and they presented the first strategies for their controlled design. This work opened up a major avenue of research into the development of new materials of this type, leading to many potential applications explored in the following decades.

Materials with controlled porosity at the nanoscale, i.e., with pores the size of small molecules, were already well known many decades before the initial work on MOFs. However, since MOFs are hybrid in nature, i.e., with parts consisting of inorganic nodes and organic ligands, the possibilities for designing the porous structure are virtually endless. In fact, over the last two decades, tens of thousands of new structures have been reported, featuring various ligands and inorganic nodes with different metal ions. These structures exhibit a wide range of properties, not only in terms of pore size, but also due to the different chemical environments that can be created within these pores. This allows liquid or gas molecules to be housed within the pores (i.e., the phenomenon of adsorption) in a more controlled, selective manner and with specific interactions with the pore walls.

Vânia André (VA) – The committee responsible for the awards highlighted that the three winners “have created new rooms for chemistry” through the “development of a new type of molecular architecture”. The metal-organic frameworks they created are important because they have large internal cavities that allow different molecules to enter and exit.

These structures, often referred to in scientific circles by their English abbreviation, MOFs (metal-organic frameworks), are materials that act as “building blocks” – metal atoms and organic molecules – linked together to form a three-dimensional framework, similar to scaffolding, obviously “super” small and invisible to the naked eye. Therefore, these compounds have many pores. It is precisely these pores (the so-called “new rooms for chemistry”) that allow different molecules to enter and exit this type of supramolecular architecture. In practice, these cavities allow gases and other substances to flow, to be stored, separated, or used in reactions, among other possible applications. In particular, researchers have used these molecular architectures to collect water from desert air, extract pollutants from water, capture carbon dioxide, or store hydrogen.

The sharing of this prestigious prize among the three researchers is justified by the complementary work they have carried out, from exploring the idea to consolidating the synthesis and demonstrating its immense potential in various applications. Richard Robson developed the initial concept, proving that it was possible to create structures with defined internal spaces. Susumu Kitagawa increased the stability and adaptability of these frameworks, allowing flexibility and the use of different metals and ligands. Omar M. Yaghi introduced “lattice chemistry”, that is, the concept of molecular blocks (like Lego pieces) to build predictable networks, in addition to creating MOFs with large internal areas to store gases such as hydrogen and capture CO₂.

The laureates’ work has thus resulted in the emergence of a new class of materials that stands out for its wide applicability in various fields of science and technology. These innovative and extremely versatile structures have paved the way for the development of materials that can be tailored to specific needs, thereby responding to the pressing needs of society. In other words, the three laureates have undoubtedly made a great contribution to humanity, thus fulfilling Alfred Nobel’s mission.

What scientific advances have resulted from the work of these researchers? What benefits could they bring in the future?

MP – These types of materials, which can hold different types of molecules inside, can be designed to be more selective for certain types of molecules than others. This allows for the separation of liquid or gaseous mixtures, water decontamination, and the capture of air pollutants. MOFs can even be designed to capture (i.e., adsorb) moisture from the air and then release it in the form of liquid water. Adsorption and desorption are accompanied by the release and absorption of heat, which allows their application in refrigeration systems. The introduction of molecules into the pores of materials can significantly alter the optical, magnetic, and electrical properties of these solids and allow their application in sensors. The high porosity of MOFs has also been explored for the storage of gases at low pressures and as vehicles for the storage and local release of molecules with therapeutic effects.

Many of these potential applications have been successfully demonstrated in the laboratory, and a reasonable number of MOF structures are now known for these applications. The biggest challenges currently facing the widespread commercial application of MOFs are related to their large-scale production in an economically viable manner and under environmentally sustainable conditions. There is also a need to adapt the form of these materials, which are normally obtained in the form of fine powders after synthesis, to the specific contexts and needs of each application. I anticipate, therefore, intense research and development activity in Chemical and Materials Engineering involving MOFs over the coming years.

VA – MOFs have been unequivocally demonstrating that chemistry plays a central role in solving major global challenges. This is because the discovery of this new class of compounds goes far beyond the work carried out directly by the three laureates.

Research on MOFs is currently being conducted worldwide by a large scientific community, focusing on specific applications and covering areas as varied as catalysis, energy, environmental solutions, medicine, and pharmacy.

Among the proven applications of these structures are efforts to combat environmental pollution, where metal-organic frameworks (MOFs) are used to capture CO₂ and remove pollutants from water, for example; energy storage, facilitating innovative solutions for storing gases and fuels; production of semiconductors, which are essential to technological advancement; and effectiveness of disease treatment, by enabling new methods for the controlled and localised transport and delivery of pharmaceuticals.

It is also worth mentioning that the advancement of MOFs has been (and continues to be!) driven by new synthesis and modification techniques, broadening the range of available materials, with tens of thousands of MOFs reported. Today, we also have methods that allow us to predict the optimal combinations of ligands and metals to optimise properties, thereby integrating experimental and computational approaches.

We are now certain that these unique molecular architectures effectively represent “new rooms for chemistry”, about which we still have much more to explore.

What other advances in chemistry would you like to have seen recognized with the Nobel Prize this year?

MP – Gérard Férey’s work was also pioneering in the development of MOFs, particularly in the concept of “secondary building units,” which are fundamental to understanding and designing more complex, robust structures with larger cavities. His work in the early 1990s with porous metal phosphates incorporating organic ligands was also of enormous importance for the development of porous hybrid materials such as MOFs. During the 2000s, he was one of the pioneering researchers in the field of porous materials, who made significant contributions to the understanding of the complex mechanisms of crystallization of these materials. Had he not passed away in 2017, his name might now be among the laureates.

Recognising the importance of sustainability in our compound synthesis research, I believe there should be a Nobel Prize awarded in the field of sustainable chemistry or green catalysis. This prize would highlight significant advancements in environmental chemistry, particularly those methods that replace polluting industrial processes with cleaner, more efficient alternatives that offer higher yield and selectivity.

One example is mechanochemistry, which is considered one of the emerging technologies with the greatest potential to change traditional chemistry. It is a technology that is used at Técnico, involving European projects underway, namely the IMPACTIVE project, of which we are a partner. This project, which aims to synthesize drugs using different mechanochemical processes, ranges from research to industry and innovation. Mechanochemistry significantly reduces solvent use in synthesis processes, thus representing a cleaner, more efficient, and sustainable approach with the potential to transform various areas, from drug production to the development of new materials, including MOFs.

I believe that mechanochemistry represents a strong contribution to sustainable chemistry and I hope that it will be recognised as such, perhaps even at the highest level.

How does your work relate to that of the award winners?

MP – Our research team has been working with MOFs for over a decade. We have conducted significant research into the application of MOFs in adsorption separation processes for use in the purification of biogas, natural gas, carbon dioxide capture, and olefin/paraffin separations. All of these separations are technically challenging, and current processes are not very energy efficient.

Another very relevant application we have been exploring is the decontamination/purification of indoor air in buildings. In addition to being important for the health of people inside buildings, there are other even more challenging situations related to the conservation of cultural heritage, as many artifacts are extremely sensitive to certain indoor air pollutants. We have been doing some interesting work on the application of MOFs over the last five years as part of the NEMOSINE project, which aids in the preventive conservation of film and photographic collections. We are currently coordinating an even more ambitious project – SIMIACCI – which involves using MOFs for the protection of cultural heritage in European museums, galleries, archives, and libraries.

In the biomedical field, we have been working for over a decade on the application of MOFs for the storage and controlled release of nitric oxide for therapeutic purposes. In 1998, researchers Robert F. Furchgott, Louis J. Ignarro, and Ferid Murad received the Nobel Prize in Medicine for identifying this molecule as a signaling molecule in many physiological processes. The main challenge of using it in therapies is its high toxicity, i.e., therapeutic effects are typically achieved at very low doses, and the fact that it is a gaseous molecule, which presents unique challenges in its application. Today, we know how to design some MOFs so that nitric oxide binds strongly inside their pores, to be subsequently released in a controlled manner in specific locations that need this nitric oxide supplement. We hope that our efforts will soon translate into clinical applications.

Finally, we have recently been very involved in the development of processes and their technical and economic evaluation for the production of MOFs. In fact, many of the expected applications require the production of these materials on a fairly significant scale. However, this will only happen if the production processes are well established and economically viable.

VA – The work carried out by the laureates represents the conceptual basis of BioMOFs (bio-inspired metal-organic frameworks). The central structure of the metal-organic framework can be adapted and targeted specifically for biological purposes and biomedical applications. BioMOFs are based on building blocks that enable the design of networks with customizable characteristics. This includes the ability to control the size and shape of the pores to tailor the networks for different biomedical applications. Furthermore, the development of synthesis methods is crucial to ensure the stability of these structures and to modulate their physicochemical properties effectively.

All these principles are fundamental for developing more efficient antibiotics and antimicrobials, innovative systems for the transport and controlled release of drugs, and for promoting selective interactions with human cells and microorganisms. Thus, BioMOFs represent a promising interface between fundamental chemistry and effective solutions in healthcare.

A key challenge in working with BioMOFs is adapting these structures to make them biocompatible, ensuring that they are safe and effective in the human body. The work developed by my research group at CQE-IMS-IST consists of using active ingredients that are already commercially available, mainly antimicrobials. By arranging these drugs as one of the building blocks of BioMOFs, we give new properties to existing antimicrobials, while also making it possible to control their release. We have already proven that this type of approach using “safe” metals, such as zinc or magnesium, also leads to a synergistic effect, i.e., it enhances the antimicrobial activity of the existing drug. This type of concept presents itself as an alternative scenario for solving issues related to the global challenge of antimicrobial resistance.

Therefore, the research on BioMOFs is closely related to that of the award-winning MOFs, but focuses on practical and alternative applications. This field of study aims to integrate fundamental knowledge into the biomedical field while addressing additional requirements such as biocompatibility, stability in aqueous environments, and selectivity for specific microorganisms.

In the media:

• “Prémio Nobel da Química: uma investigação que pode servir para encontrar água no deserto” Com: Moisés Pinto (TSF)
• “Técnico já explora a descoberta premiada com o Nobel da Química” Com: Moisés Pinto (Notícias ao Minuto)
• “Instituto Superior Técnico já explora a descoberta premiada com o Nobel da Química” Com: Moisés Pinto (Correio da Manhã)
• “Instituto Superior Técnico já explora a descoberta premiada com o Nobel da Química” Com: Moisés Pinto(Observador)