The 2021 Nobel Prize in Chemistry has just been awarded for the development of a precise new molecule-building tool.
Benjamin List from Germany and Scottish-born David W.C. MacMillan jointly received the prize for this new tool, known as asymmetric organocatalysis. So what is it?
Building new functional molecules is key to many types of research, from creating efficient solar cells to producing everyday substances like pharmaceuticals, plastics, perfumes and food flavourings.
Chemists rely on catalysts to control and speed up the process of building these molecules. But for years they thought only two groups of catalysts existed – metals and enzymes.
However, in 2000, List and MacMillan independently developed a third type: asymmetric organocatalysis.
List discovered that instead of using a whole enzyme to spark a chemical reaction, you can just use one of its constituent amino acids – proline, which is cheap and environmentally friendly. Meanwhile, MacMillan similarly found that simple organic molecules with the correct properties can also make excellent catalysts.
This technique takes molecular construction to a whole new level. It allows chemists to build asymmetric molecules, where two molecules are each other’s mirror image. This is hugely useful in pharmaceutical research.
Over the last two decades, List and MacMillan have produced many cheap and stable organocatalysts. They have also made chemical manufacturing “greener” because several steps of the production process can be performed in an unbroken sequence and therefore reduce byproducts and waste.
For example, in 1952 it took 29 different chemical reactions to produce a strychnine molecule, and only 0.0009% of the initial material made it into the strychnine. But now, chemists can use organocatalysis to build strychnine in 12 steps, making the production process 7,000 times more efficient.
This year’s Nobel Prize in physics was awarded to three scientists. Firstly, it was awarded jointly to Syukuro Manabe, of Princeton University, US, and Klaus Hasselmann, of the Max Planck Institute for Meteorology, Hamburg, Germany, for “the physical modelling of Earth’s climate, quantifying variability and reliability predicting global warming”.
Manabe and Hasselmann were some of the first scientists to investigate the relationship between CO2 production and global warming. In the 1960s, Manabe demonstrated how increased CO2 in the atmosphere leads to increased surface temperatures on Earth. Ten years later, Hasselmann created a model that linked weather and climate together, explaining why climate models can be reliable despite the turbulence of weather.
The Royal Swedish Academy of Sciences says Manabe and Hasselmann’s work “laid the foundation for the development of current climate models”.
Manabe himself was pleasantly surprised by the award, which he says is usually awarded to researchers probing the depths of physics itself; this is the first time it’s been awarded for this kind of applied physics.
The other half of the award was given to Giorgio Parisi, of Sapienza University of Rome, Italy, for “the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”.
In the 1980s, Parisi discovered hidden patterns in disordered complex materials, which made it possible to understand and describe different and apparently entirely random materials and phenomena, not only in physics but in mathematics, biology, neuroscience and machine learning – as well as in weather and climate.
Crucially, while the study of complex physical systems has broad applications, the Nobel Committee highlighted the use of physics to understand perhaps our most crucial complex system, the Earth’s climate.
“The discoveries being recognised this year demonstrate that our knowledge about the climate rests on a solid scientific foundation, based on a rigorous analysis of observations,” says Thors Hans Hansson, chair of the committee. “This year’s laureates have all contributed to us gaining deeper insight into the properties and evolution of complex physical systems.”
Medicine or physiology
This year’s Nobel Prize in physiology or medicine was awarded jointly to David Julius and Ardem Patapoutian for their discoveries of the receptors for temperature and touch.
Julius used capsaicin, a pungent compound from chilli peppers that induces burning, to identify a sensor in the nerve endings of the skin that responds to heat, while Patapoutian used pressure-sensitive cells to discover a novel class of sensors that respond to mechanical stimuli in the skin and internal organs.
Both of these discoveries paved the way for a deep understanding of how our bodies respond to heat, cold and mechanical stimuli. This knowledge has material implications, with both discoveries being used to develop treatments for a range of conditions, including chronic pain.
Amalyah Hart is a science journalist based in Melbourne.
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