Heiner Linke (left), Chair of the Nobel Committee for Chemistry, explains a model as Hans Ellegren (centre), Secretary General of The Royal Swedish Academy of Sciences, and Olof Ramstroem, Member of the Nobel Committee for Chemistry, listen during a press conference on the announcement of the winners of the 2025 Nobel Prize in Chemistry at the Royal Swedish Academy of Sciences in Stockholm, Sweden, on October 8, 2025. Japan’s Susumu Kitagawa, UK-born Richard Robson and American-Jordanian Omar M. Yaghi won the Nobel Prize in Chemistry for developing so-called metalorganic frameworks, the Nobel jury said on October 8, 2025.
| Photo Credit: AFP
The story so far: For centuries, chemistry’s main terrain was to craft ever more complex molecules but it soon became clear to scientists that they were all confined to their own boundaries. The Nobel Prize in Chemistry 2025 honours three scientists who expanded that horizon into a whole new dimension. Susumu Kitagawa, Richard Robson and Omar Yaghi have been feted for developing metal-organic frameworks (MOFs), little molecular scaffolds with vast internal spaces where other atoms and molecules can move, react or stay.
What is a MOF?
MOFs are crystalline structures in which metal ions serve as nodes and organic molecules as connectors. The resulting structure can have enormous internal surface areas — thousands of square metres per gram — and their pores can be customised to attract or hold specific molecules.
Chemists classify MOFs as part of a larger family called coordination networks but their hallmark is tuneable porosity. By carefully choosing the building blocks, researchers can control the size and shape of the cavities and the chemical environment within. As a result, MOFs are among the most versatile materials ever created.
What did Robson and Kitagawa do?
In the 1970s, Richard Robson at the University of Melbourne was preparing ball-and-stick models to show students how atoms connect. He realised that the positions of the holes drilled into each atom contained all the information needed to determine the molecule’s shape. If that logic worked for small molecules, he wondered, could it be scaled up?
A decade later, Robson combined copper ions, which like to bond in a tetrahedral arrangement, with an organic molecule bearing four arms ending in nitrile groups. To everyone’s surprise, instead of a messy tangle, the components self-assembled into a diamond-like crystal. This lattice wasn’t dense like diamond but full of empty cavities, each capable of hosting other molecules. Robson predicted that such “frameworks” could be tailored to trap ions, catalyse reactions and sieve molecules by size.
However, Robson’s early crystals were fragile. Susumu Kitagawa in Japan made them stable and functional. Guided by his philosophy of finding “usefulness in the useless”, Kitagawa pursued porous materials even when they seemed too delicate to matter. In 1997, he used cobalt, nickel or zinc ions linked by a bridging molecule called 4,4’-bipyridine to build a true three-dimensional MOF. When the material was dried and refilled, gases such as methane, nitrogen, and oxygen could flow in and out without damaging the structure.
Kitagawa also recognised that MOFs could be soft rather than rigid, with flexible molecular joints allowing them to expand, contract or bend around depending on temperature, pressure, and the molecules inside.
What was Yaghi’s contribution?
Omar Yaghi in the U.S. gave MOFs their structural strength and reproducibility. Having grown up in modest circumstances in Jordan, Yaghi was fascinated by chemistry’s ability to create new forms of order. At Arizona State University in the 1990s, he sought a way to build extended materials by design, not by chance, using metal ions as joints and organic molecules as struts.
In 1995, he made the first two-dimensional frameworks linked by cobalt or copper ions that could host other molecules without collapsing. Four years later, he achieved a landmark with MOF-5, a robust three-dimensional lattice made from zinc ions and benzene-dicarboxylate linkers. MOF-5 was strong and, notably, just a few grams had an internal surface area comparable to a football field. It was also intact when heated to 300°C and emptied of all ‘guest’ molecules.
By the early 2000s, his team had built entire families of MOFs with the same underlying geometry but different pore sizes and functions.
Why do MOFs matter?
Say you have a tennis ball with a surface area of X. Say its outer shell is 5 mm thick. What will the total surface area be when you cut open the ball? It will be 2.2-times X (proof available on request) — which is a little illustration of the ‘magic’ of surface areas. The same ball yielded some surface area first, then with a single modification that didn’t add any new material yielded 2.2X! This fact explains one half of the allure of MOFs. The other half has to do with how easily chemists can make them for different applications.
A MOF called CALF-20 can efficiently capture carbon dioxide from factory exhaust and is already being tested in industrial plants. MOF-303 can harvest drinking water from arid desert air by absorbing vapour at night and releasing it in sunlight. UiO-67 can remove persistent forever chemicals (PFAS) from water. MIL-101 and ZIF-8 can speed up the breakdown of pollutants and recover rare-earth metals from wastewater.
In the energy sector, NU-1501 and MOF-177 can store hydrogen or methane safely at moderate pressure, a crucial step toward clean-fuel vehicles. Others serve as containers for toxic gases in semiconductor manufacturing and as drug-delivery capsules that release medicines in response to biological cues.
Published – October 08, 2025 06:51 pm IST