Creating new molecules is often such a delicate and complex process, that to the uninitiated, it almost seems like an arcane art. But while there’s undoubtedly an element of creativity to producing new molecules, there’s a lot more hardcore science that goes into it. Thanks to the work of Benjamin List and David W.C. MacMillan, chemistry is one step further in our understanding of this process.
The two were awarded the Nobel Prize for Chemistry in 2021, “for the development of asymmetric organocatalysis,” a process that can be used in the creation of various compounds of economic importance. As the “newbies” in the Chemistry Nobel Laureate club, they hosted two separate lectures in which they presented what makes their work (and catalysis, in general) so important.
Catalysis Makes the World Go Round
“Over the years I realised that catalysis is among the most relevant cultural human accomplishments in the history of mankind,” said Benjamin List in his lecture. “It’s comparable perhaps to agriculture or the wheel or cars or the internet. It is probably the single most important technology for our future. That’s my key message today.”
If you think he’s exaggerating, well, he’s not. Many industries and research areas are directly dependent on chemists’ ability to construct molecules with the desired properties, and this work requires catalysts substances that control and increase the rate of a chemical reaction undergoing any permanent chemical changes themselves. Approximately 80% of the processes in the chemical industries require the use of catalysts and directly or indirectly, catalysis contributes to 35% of the global GDP. But probably the most important catalysis reaction on Earth isn’t even made by humans, it’s made by plants. We’re talking about photosynthesis.
“I’d like to start with by far my favorite chemical reaction, photosynthesis. I couldn’t envision a more beautiful process on this planet in which a plant converts CO2 from air and water to make the materials we eat and the air we breathe, accomplished by the utilization of light. Is there anything more useful for us on this planet?”
Another key catalysis area is the production of ammonia. Ammonia is a key element in the Green Revolution or the Third Agricultural revolution, which enabled mankind to reach the population we have now. In fact, as List highlights, the production of ammonia correlates excellently with global population, and it’s hard to think that without catalysis, our population growth would have been achievable.
Making it General
Of course, producing different type of compounds require different types of catalysis. In his lecture, David MacMillan didn’t focus on the organocatalysis that led him to the Nobel Prize but instead, discussed another type of catalysis: Photoredox catalysis.
Where organocatalysis uses an organic compound to control or increase the rate of a chemical reaction, Photoredox catalysis uses light-induced single-electron transfer. Basically, it’s a branch of photochemistry that “develops new reactivity” and uses visible light to power new organic chemical reactions, MacMillan explains. The choice of topic for the lecture says a lot about how dynamic the field of catalysis truly is. Organocatalysis is a relatively new field with plenty of untapped and underdeveloped potential, and yet researchers are already looking at other options.
“So one area of this that my group has focused on this is metallic photoradox. The idea is to use the key steps and merge it with metal catalysis. The goal here is to take these two completely different types of catalysis to hopefully allow you to make bonds in a new (faster) way.”
It’s a promising approach, MacMillan explains, but the challenge isn’t getting it to work – it’s getting it to always work; or rather, to get it to generally work. “I would argue the most important reactions in the world are important because of the bonds that take place, but also because they’re general,” MacMillan says.
So how do you approach generality? There’s no universal recipe, unfortunately; it takes a lot of time and hard work. But talking to industrial partners who are trying to deploy academic ideas into large-scale practice can help. His work with pharmaceutical companies has helped zoom in on some of the real-life problems associated with catalysis and encouraged him and his team to find new solutions to these problems.
Both laureates took a moment to thank their research groups and share their appreciation to their team. Looking at the images with dozens of young, smiling researchers, and hearing about how “we” won the Nobel Prize, one can’t help but feel a deep sense of camaraderie – and without a doubt, we can expect plenty more to come from these research groups (and from the young researchers in the audience).
Despite decades of research, catalysis is still a very rich field with plenty of untapped opportunities. Perhaps, List suggests, we may one day be able to use catalysis to replicate an artificial version of photosynthesis, which could help us tackle climate change.
“The essence of photosynthesis, take CO2 and convert it into C and O2, nobody has ever worked on it, it might not be possible, but think about it conceptually, you have to take out the CO2 out of the atmosphere and turn it into something stable or useful. I hope this inspires you.”
MacMillan also recalls an unexpected direction in which the Nobel Prize took him. As it happens, winning a Nobel helps you meet all sorts of interesting people. Among others, MacMillan got the chance to meet William Shatner, who famously played Captain Kirk in Star Trek (or is it that William Shatner got the chance to meet MacMillan?). Among other discussions, MacMillan got the chance to explain to Cpt. Kirk what a photon is.
So if you needed more motivation to try and earn a Nobel, in addition to advancing human knowledge and making the worldof better place, you may get a chance to explain what a photon is to Cpt. Kirk. If that doesn’t motivate you, then what will?