Interview with Sir J. Fraser Stoddart on 6 December 2016, during the Nobel Week in Stockholm, Sweden.
Fraser Stoddart, welcome to Nobel Week in Stockholm.
Fraser Stoddart: Thank you.
All Nobel Laureates are asked to bring an artefact to donate to the Nobel Museum here in Stockholm, what did you bring?
Fraser Stoddart: I brought some my toys that were constructed when I was at the University of Sheffield. These particular models date to somewhere in the mid-eighties, they are showing signs of wear and tear. The history to them is that they were made in the workshop of the chemistry department at Sheffield, which was one of the very best, I think, in the whole of England so they produced these models very quickly and easily.
Can you show what it is?
Fraser Stoddart: This is some sort of metal bar, and there’s magnets inserted in each end. What I’m doing at the moment is putting these so-called stoppers, when you come to describe this dumbbell, so, this is the rod push, and these are the two stoppers. The two stoppers are the artefacts from the systems of toilets. This is the ball cup that floats up and down. So, I think this was quite imaginative of part of the people in the workshop, to use that principle. And then that rests there, and if I take one of these rings, then we go from, what is a molecule here, a dumbbell, and one of the ways that we device of making this particular rotaxane, and it is there it goes to the green unit, is to clip around the green unit like this. This gives us a rotaxane because now we have the dumbbell, which …
What did you call it; this gives us the …?
Fraser Stoddart: rotaxane. So, it gets its name from rota, that’s Latin for wheel, and axis, Latin for axle. So, this is the axel, if you like, and this is the wheel.
So, this is chemistry …?
Fraser Stoddart: This is chemistry.
… that you are building right now?
Fraser Stoddart: Right, and this is an expression of the so-called mechanical bond. The blue part is not linked by classical, chemical bonds; covalent, coordinated bonds, any of these bonds, to the dumbbell portion. And so, this is now another molecular world. We started off with the dumbbell, as a molecule, we started off with the blue ring, as a molecule, but when we clip the blue ring together on this dumbbell, we then create another molecule.
And why do you want this molecule that you create in this shape, with a ring and a rod?
Fraser Stoddart: Well, it gives you the basis for having a switch. The rod portion contains two recognition sites, we sometimes call them stations. These are the places where the ring prefers to sit, at any one time. Now, when it’s sitting there it’s shivering back and forth, in the real world. And we have a green site, which is associated with something called tetrathiafulvalene, and the blue ring prefers to sit there nine times out of ten. So, this is nine times there, and only one here. It is what we call a non-degenerate rotaxane, or a molecular switch. We have the first inkling of a molecular machine. It’s not a machine yet, it’s a molecular switch. And what we can do is, we can speak to the green unit; we can take electrons out of it, and I should paraphrase what I am going to say by telling you that there are already four positive charges in the blue unit. And if I take two electrons out of the neutral green unit, then we have like charges repelling each other. And so, the ring decides that it would be better off to move there. And spends literally 100% of its time there, while there is charge on the green unit. But if you deliver electrons back and make it neural, then this ring will make its way some more slowly back to there.
So, you can steer the blue ring on the rod?
Fraser Stoddart: Yes. And you can make it switch.
And make it switch.
Fraser Stoddart: And you can put many of these into a device and you can then create a molecular random-access memory based on this principle.
So, you can make movement, and memory, and it’s a fundament for the molecular machines?
Fraser Stoddart: Well, /- – -/ machines yet, this is molecular electronics, so we have something that switches. To go to molecular machines, I don’t have a model to explain that phenomena. I’m going to talk about it on Thursday in my lecture, one has to go a step further, one has to do work. A switch does not involve the work; we started there, we went here, we went back there, but we have to go a step further, when we go to make a molecular machine.
Ok, of course. Is this something you want to show too?
Fraser Stoddart: I just want to mention that this is two interlocked rings, and this was our first contribution to this field, as was Jean-Pierre Sauvage’s; he described his first two catenates. So, he had a metal involved, as a template. We dispensed with the metal and only used the recognition between organic components. So, our 1989 publication in Angewandte Chemie, was our first major contribution to the field. We had used however, I have to say, a whole decade, choosing the right chemical constituents for the blue component and for the red component.
It took you a decade from the first publication in this field, for you to get to your discovery.
Fraser Stoddart: It’s always very difficult to say when it started, but I would say 1981 was when we started the pursuit to get the components. And these components ironically came from my spending a period of three years on secondment to Imperial Chemical Industries, ICI, as it is at shorthand, corporate laboratory at Runcorn in Cheshire. And it was there that I got introduced to, ultimately, herbicides called Paraquat and Diquat. These two chemical compounds were used in a mixture for many years to just wipe out green life, so you could use it to clear your path. They exported it to United States to …
Fraser Stoddart: … to Idaho, also to get rid of the potato greens before the machinery came in to harvest the potatoes. For many years, this was the most important herbicide on the market. And it is these components, Diquat and Paraquat, that get built into these artificial, molecular switches. Of course, we use the same principles as biology uses ultimately in terms of interactions between aromatic rings, hydrogen bonding, and so on and so forth, but that was where the bits and pieces came from; it came from my time at ICI.
But if we go back in time a little, what brought you to science, I understand you grew up on a farm?
Fraser Stoddart: Yes, I grew up on a farm, about twelve miles south of the capital of Edinburgh. It was a tenant farm, in other words we didn’t own it, we paid a rent every six months. My father moved there in 1942, the year I was born, when I was six months old. He had come into farming as a student of farming. He had been to the agricultural college in Glasgow, and the job that he left to go to the farm, being the farm manager of the University of Edinburgh’s farms. But when I was born, my parents obviously took the decision that it would be better be a little bit more independent, so that’s what took them to a farm called Edgelaw Farm, where I spent the first 25 years of my life. We did not have electricity until I was seventeen, in 1959, so it was quite a challenge just living on a daily basis. And it was a so-called mixed arable farm, so we grew everything that you could conceivably grow in that part of the world. Rather similar I guess to what you would grow in Sweden on a farm; potatoes and other root crops, oats, barley, wheat. And then we had a dairy, so we had milk cows, we had lots of sheep, and we had, my mother looked after hens, we never had pigs, my father loathed pigs, so it was a very mixed situation.
It sounds like a very wonderful way of living, but I guess a lot of hard work too?
Fraser Stoddart: It was a lot of hard work, but I actually call it the university of life, it is as important as any of the universities that I trained at because it gave me the opportunity to get involved in engineering, the first motor cars and tractors was so simple that you could take them apart. And you had to, in order to make them efficient again. They would get cooped up with carbon in their cylinders and so forth. And one had to clean them out and put them back together again. So, I had a good introduction to engineering if you like, on a macroscopic scale, on a big scale.
So, you worked actively on the farm until you were 25?
Fraser Stoddart: Yes, and then I went to Canada, and within, I see, 18 months on my going to Canada, my parents decided to leave the farm. So, I was very important, a very integral part of that farm.
But what brought you to university studies?
Fraser Stoddart: My parents had always had a huge influence on me, on the respect of putting education very high. I had three wonderful years at the local village school with a very good teacher, called Miss Morrison. And this was the type of schooling where all the children were brought together. And when I started there were five of us, there were four girls and Fraser, and Fraser learned to knit, just because I was in the minority. When I left the school, I think we were 28, three years later in 1950. So, my parents decided that I should go to a school in Edinburgh, it was called Melville College, and I had the most marvellous education there. Both through the rest of my primary and secondary education. And I look back on it, I didn’t appreciate it at the time, but I think that …
Fraser Stoddart: Just because my teachers, when I think about it now, could all have been professors at a university. They were very, shall we say, erudite people, with great teaching skills. And it went far beyond the classroom. They would take us to concerts, they would take us on hikes, it was just absolutely marvellous when I think back on it. So I am actually going back to, not quite this school, /- – -/ as it was a little bit small, but another bigger school, sometime, I think in the 1970s, and I went back to that school on my way back from Stockholm to Chicago.
Wonderful. And how come you chose chemistry? And at what stage did you choose chemistry in the university?
Fraser Stoddart: The story is the usual one; I had two marvellous chemistry teachers at Melville College, and I just got absolutely fascinated by the subject as I saw it then. I was never very switched on by smells of bangs. So, it was a process over many years of falling in love with the subject. And I think it was more the wonder of doing something in life, that might end up being useful. And also allow myself to be creative and I think this is the signs where, since you make the things that you work with, you are also part artist. And I think that’s, without actually really consciously realising that, this is what subconsciously drew me into chemistry, more and more. So, the story about why I got into research is quite interesting, because it plays back to the farm. I’m in my third year at Edinburgh, it’s 1963, an analytical chemist was holding a course, has a class of maybe 150 of us. And he makes two comments, he says “There’s enough cyanide in the lab, and we are going to pipette it, to kill the whole of Edinburgh”. And we all kind of looked at each other and felt terrified. And then the next thing he said, he went over the top, he said “I devised this course many years ago, and it’s a tenure course, and nobody’s ever finished it”. And well, the short story is I finished it in seven weeks. How? Because I multitasked; I didn’t do one experiment after the other, in a linear sequence, I did three experiments at once. So that brought the opportunity to go into the research lab under the guidance of this person.
How did you get the idea to do all these experiments at same time, instead of one at the time?
Fraser Stoddart: On the farm. Because on any day on the farm, particularly, say, in the spring, we would be milking cows in the morning, there would be sheep in the paddock close by having lambs. There would be the need to be doing the last stages of ploughing in order to sow some oats or barley, maybe the wheat had been sown the winter before, and getting ready to put the root corps in, and … There would be somebody who need to clean out the hen houses so, there were so many things going on in one day, that …
So that was the way you were used to solving problems?
Fraser Stoddart: That was the way I was used to. And I find that the students I was alongside, they were thinking in a linear way, whereas I was thinking in a, it’s just like being on a farm. And I used the same principles that I had been instructed on in many ways on the farm, and I could make this piece of lab work less of a linear situation and finish it a bit earlier.
Going a little bit further in time, do you remember how you got the idea, the thinking of how to make this, what is it called? Rotaxane?
Fraser Stoddart: Rotaxane, in more general terms, mechanically interlocked molecules. So, introducing this new bond into chemistry, that I think Jean-Pierre Sauvage was right in the vanguard of, I was following. As it turned out I think it’s a major advance, and so far as, I often put it this way; probably every day, a thousand or two, or three chemical compounds are invented or made, all around the world in different laboratories. There’s only once in a blue moon that a new chemical, or new bond I should say, comes along. And this is a physical bond rather than a chemical bond. So, it was waiting to be done. It had been talked about from the beginning of the 20th century. There were so called ‘chatter in Zürich’ by some of the eminent chemists of the days, around about 1910. One of these, I think was Professor Prelog who was a Nobel Laureate, somewhere later on in life of course. And then not much happened until about the 1950s. There were a few /- – -/ into making mechanically interlocked compounds, particularly used catenanes, but the chemists of the day were, struggling, because they were trying to match like with like, and that was not giving them very much success. At the very best they could get less than one percent yields relying on statistics.
Do you remember the moment when you started thinking that “Hm, maybe I can do it this way”?
Fraser Stoddart: This was when I was in ICI, it was when I realised that we had the bits and pieces, that were talking to each other, that were entering into molecular recognition. To be more precise, bipyridinium systems, this is what the herbicides were based on, a π-electron deficient. And then we reasoned that aromatic rings, particularly with oxygen atoms connected to them, would be π-electron rich. And these, we knew, stacked together, this was well recorded in literature. What we were building on of course, was the work of Jean-Marie Lehn and Donald Cram and Charles Pedersen, the people who got the 1987 Nobel Prize and what is now called supramolecular chemistry. We were building on that, in a sort of conceptual way, to see if having brought the pieces together, we could then, as it were, do something to nail them together. So that there would either be two rings, that wouldn’t part unless you broke the weakest covalent bond in the molecule, the weakest chemical bond, or this other construct, were you had the dumbbell shape, and you have one or more rings on it, and the rings can’t leave, because their inner diameter is much less than the outer diameter of the stopper. Part of it also came from my fascination with Meccano when I was a boy and also with jigsaws in an earlier stage when I was a very young boy. I used to make jigsaws by the dozen and pile them up between paper until my mother said “No, they are getting brown this paper, it is beginning to small Fraser, you can’t do this”. So it was a combination of, if you like, Lego, as we now know it, in two dimensions and this whole business of Meccano, which is another form of toy, that allowed you to be creative; you didn’t have to follow the guidelines and the pamphlets, you could create your own object.
You must have been excited when you started to feel that you were getting close to the solution?
Fraser Stoddart: Yes, but frustrated that it took a decade, almost, it took about eight years from ’81 to ’89.
Did you ever think of giving up, that this won’t work?
Fraser Stoddart: No. I did, and I think this is true for many of us who are in this sort of situation, take a lot of criticism. My students took it even more so, because, I guess senior people felt ultimately that they could attack students easier than they could attack me. But, if you know something about creativity, and I read some books, it was no surprising that some of these ideas were being held up as well, it’s exotic, it’s maybe interesting, but it’s going to be good for anything, alright. So, we got a lot of that in the 80s and 90s, and I’m sure that Jean-Pierre Sauvage had the same experience. Times move on and it becomes interesting and the chorus of dissent disappears, it becomes quiet, and there’s a high interest and one day the phone rings from Stockholm …
I understand you also need a lot of self confidence and believe in your science, to come this far. What more is needed to get this far and actually being rewarded the Nobel Prize and getting this telephone call from Stockholm?
Fraser Stoddart: I usually sum it up in a three-line statement. You need the strength of a horse, and that I gave in the farm, because I was up in early hours moving food, turnips, to animals, or in harvest, moving big bags of green off something. So, you need the strength of a horse. Which also mean that you don’t fall ill. What ever happens, you eat well, and you make sure that you are fit. You need the height of an elephant, in other words, you need to be able to take the barbs of criticism and, for the most part, ignore it. You might be some things that you would take on board, but for most of it you got to say, “Well, I know what I’m doing I must continue”. And then, on top of that, and this is going back to the farm again, you need the work ethic of a honeybee.
Fraser Stoddart: Because I don’t think many people succeed, in science or anything else, at a very high level, and we can go to the people who are running recently, in one shape or other, in the Olympic games, they don’t turn up there just to do something for a week or two or three. They’ve been practising for years.
A lot of hard work?
Fraser Stoddart: A lot of hard work, a lot of training. I have a great sort of national empathy with the number one tennis player in the world today, Andy Murray. And that again, is a study of a lot of hard work. With an enormous number of tennis players who are extremely gifted that he has had to compete against over years.
Do you think he or you have been working most hard, so far?
Fraser Stoddart: Well, he has to work hard to achieve what he does in life, in a very short period of time. Somewhere probably over 20 years at the most. I think in science, and this is almost inevitable in the case of chemistry, it’s 50 years that you have to work hard and keep your head down and wait and see what happens.
I guess you need a good team to work with too?
Fraser Stoddart: Absolutely.
How do you put together a good team?
Fraser Stoddart: I’ve learnt over the years. I have a very much open-door policy, and I’ve used this for many decades now. Once we saw that we had a new story to unfold, I would just say to the brightest and best of my students, and that was virtually all of them, between the ages of 22 and 32, “Go away tonight and think of 39 new ideas that we can talk about in the morning, we’ll throw away 38 of them, and we’ll just deal with the very best that come up”. I opened up the possibility for, in these later stages of my career, for it not just to be my input, but the input of ultimately, often 35 people, that’s about the size of my group through the 90s, and the last 15 years of this millennium. And it is just amazing. There’s about 40 of them I have invited to come here. I have just taken people from different eras, to represent the creativity of these individuals. And so, the post doc who made olympiadane is one of these people, David Amabilino, and there are many others, people that are working on molecular machines in my lab today. There’s an Italian post doc and there’s a Chinese graduate student who are just off-scale /- – -/. So I have recognized effectively, that you put a team together and you allow the brains of 30 people to work on something, rather than a top-down approach, where you say “I have all ideas”, and these are just, ultimately, pairs of hands or slaves. No, no, no. And part of this is because that is how I was kind of treated as a young scientist.
So, I am rebelling against the hierarchical system that visited me in the early part of my career. I said “I am not going to go down that road, I am going to fashion something that’s new”. I’m going to make it possible for young people, with amazing talent, to express their creativity. I guess that brings me to the next point, that often I say “I’m not in this anymore to do research, I’m in this, as a professor, to teach”. And so, my main legacy may not be my rotaxanes and my catenanes, but the more than one hundred people, who are in academia, all spread around the world. There are more than one hundred people who are in industrial companies and often in high places. And the one or two that are sprinkled in government. One of them, for example, is the funding editor of Nature Chemistry. He is here in Stockholm, looking after us all, because he has a great connection with the whole of the chemistry community. So, I /- – -/ about this, the people that have been around me and I hope them to do better than me.
I must ask you, is there anything that you do, that annoys your team, that they can laugh about?
Fraser Stoddart: There’s one or two things. I have terms of phrases that they don’t understand and that’s part of the ‘Stoddart legacy’, that I use a lot of idioms. And of course, people coming with not English as their first language, let’s take the Chinese, or any European in fact, might be struggling to begin with to understand: “What the blazes is he talking about?”. The other thing is that, in order to put out a publication, we very often go through 50 drafts. And of course, my red pen treatment of manuscripts is part of their training. And they’ll talk about it endlessly: “How many times have you been red penned?”. But I should add that I do it to myself. I’m giving the banquet speech, and that went through 100 drafts, and I went out to three or four selected people to ‘put red pen’. And it was improved a lot during maybe about a 10-day period or so, as a result of that process.
So, you really like the red pen?
Fraser Stoddart: I think yes, you need comment and criticism to do better.
Thank you very much for the interview Fraser Stoddart and enjoy the rest of your week here in Stockholm.
Fraser Stoddart: It’s been a pleasure talking to you, and I will certainly have fun this week – I intend to enjoy every minute of it.
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