Chemistry for Everyone
Chemistry, Creativity, Collaboration, and C60: An Interview with Harold W. Kroto Liberato Cardellini Dipartimento di Scienze dei Materiali e della Terra, Università Politecnica delle Marche, 60131 Ancona, Italy;
[email protected] Harold Kroto is Professor of Chemistry at Sussex University and President of the Royal Society of Chemistry (UK). He received his Ph.D. in 1964 for research work with R. N. Dixon on high resolution electronic spectra of free radicals produced by flash photolysis. After three years of postdoctoral research at the National Research Council in Ottawa, Canada, and Bell Telephone Laboratories in Murray Hill, NJ, USA, he started his academic career at the University of Sussex (Brighton, UK) in 1967, where he became full professor in 1985. In 1991 he was made a Royal Society Research Professor and since 1990 he has been chairman of the editorial board of the Chemical Society Reviews. Harry Kroto’s research program has covered several interdisciplinary areas. His main research areas include: spectroscopy of unstable species and reaction intermediates (infrared, photoelectron, microwave, and mass spectrometry); cluster science (carbon and metal clusters, microparticles, and nanofibres); fullerenes (chemistry, physics and materials science); and astrophysics (interstellar molecules and circumstellar dust). As chairman of the board of the Vega Science Trust (http:// www.vega.org.uk), he promotes Vega’s work across the globe. The Vega Science Trust aims to make available a broadcast platform for science, engineering, and technology to show the true face of science as an important part of our cultural heritage.
Harry Kroto is an enthusiastic and passionate man. He communicates his passion for science while giving lectures, presentations, and workshops to groups of all ages, including thousands of children. Outside of his scientific interests, Kroto likes playing tennis. His great passion, however, is graphic art and design: in 1964 he won the Sunday Times Book Jacket Design competition and in 1994 the Moët Hennessy–Louis Vuitton Science pour l’Art Prize. Kroto’s importance as one of the founders in the field of fullerene chemistry was acknowledged by having a knighthood conferred on him. His work has been recognized with many scientific awards and honorary degrees. In 1996 he was awarded the Nobel Prize for Chemistry along with Robert F. Curl, Jr. and Richard E. Smalley for their discovery of fullerenes (1). The Interview Harold Kroto, Nobel Laureate, is famous for his work on fullerenes. This interview offers insights into how his discoveries, and his interpretation of them, were influenced by his other interests in the wider fields of chemistry and by his passionate interest in art. He also has some strong views on how chemists of the future should be educated to foster creativity. Liberato Cardellini: Why don’t we begin with a brief biography—How did you become a teacher and why did you choose a career in academics? Harold Kroto: Well, I didn’t actually choose it; I was doing a Ph.D. (after a first degree) at Sheffield in spectroscopy and then I went to Canada to do a post-doc for two years. Then I thought I’d like to live in the USA and I got a job at Bell labs for a year. Then my boss there took a job in a university and I was offered a fellowship in the University of Sussex. I was always considering that perhaps I might go into graphic art and design but as I was offered a university position back in the UK, I thought I’d take it for a year or so and see how things went. About six months after I got back from the States, I was offered a permanent position at Sussex. I then decided to see whether I liked research and lecturing. It went pretty well and in the end I stayed and carried on in academia.
C60, a closed [12P:20H] shape. Kroto remembers that “we came to the conclusion that the C60 molecule might be a beautifully symmetric soccerball structure with twelve pentagons and twenty hexagons.... In fact the crucial moment for me came when I realized that the first structure that could close without all the pentagons abutting was C60. That was an important moment because I realized that you need twelve pentagons to close any network of hexagons. You can’t do it with only hexagons.” (p 752 f ).
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Could you say something about your research before September 4, 1985? Between 1967 when I got back to the University of Sussex and 1985 when C60 was discovered, I undertook many research projects. I studied Raman spectroscopy of liquid state interactions looking into intermolecular forces. I did some flash photolysis studying the electronic spectra of molecules—
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which is what I had done for my Ph.D. I then went on to work on the microwave spectra of small molecules and those really were some of the most successful areas between 1969 and 1985. In fact, the work I am most proud of is the creation of the first C=P species—CH2=PH is my favorite molecule (2, 3). Some people may think it is C60, but actually it’s CH2PH. We also made molecules with C≡P triple bonds, which are called phosphoalkynes and phosphoalkenes with the double bond. We made boron sulfur compounds also, and some C=S compounds—thiocarbonyls. I also did some infrared spectroscopy, a lot of photoelectron spectroscopy, as well as interstellar spectroscopy, so all aspects of spectroscopy. An interesting project that I started with David Walton at Sussex was the study of long carbon chain molecules and the original work was done with an undergraduate, Anthony Alexander and also with Colin Kirby. This led to a project to try to see whether the carbon chain molecules existed in the interstellar medium and I got together with a friend at NRC (National Research Council) in Canada with whom I’d been a post-doc, Takeshi Oka, and we tried to detect the carbon chain molecule in interstellar space by radioastronomy using the telescope in Algonquin Park in Canada. We did that with Canadian astronomers, Norm Broten, John MacLeod, and Lorne Avery, and we were incredibly lucky because we found them. It was a very exciting period between 1975 and 1980 as we found that longer and longer chains existed in the interstellar medium. Buckminsterfullerene The discovery of buckminsterfullerene is a beautiful story and an example of interdisciplinary cooperation. Could you tell us about it? As time went by infrared and radio techniques developed and one could look at the emission from stars, cold stars, old stars, carbon stars, and the carbon chain molecules that were found in them. I had to try to understand how the carbon chain molecules were made. The idea I was developing between 1978 and 1985 was that the carbon chain molecules probably were made most efficiently in the circumstellar shells of carbon stars. Carbon stars have a carbon to oxygen ratio greater than 1. Oxygen stars have an oxygen to carbon ratio greater than 1. I thought that in the circumstellar shells of such stars where the gas is warm and moderately dense it would be possible for long carbon chain molecules to form. That was in my mind for quite a long time; I wasn’t really thinking hard about doing an experiment—it was just in the back of my mind. It was on a visit to Austin, Texas that I passed through Houston to see Bob Curl and he suggested I see Rick Smalley who had developed some fantastic apparatus for vaporizing metals such as aluminium and iron. If a laser is focused on a refractory material such as a metal and the spot is so hot— 5000–10,000 °C—it can vaporize the metal at that point. If you look with a mass spectrometer at the material that comes off in helium the plasma cools and condenses to form clusters. These clusters might have say 10, 11, 12, or 15 metal atoms stuck together. It seemed to me that this was an ideal method for making carbon chain molecules and testing the idea that maybe they were made in circumstellar shells of stars. 752
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The idea was to simulate the chemistry in a star shell and that was the experiment we carried out a year later in 1985 (4). I went to Houston and with students Jim Heath, Sean O’Brien, and Yuan Liu we got the carbon chain molecules as I had predicted but at the same time we found that the C60 molecule formed. So really you could say that it was the combination of the development of a superb piece of experimental apparatus that could make clusters of molecules from the refractory material with ideas that came from radioastronomy and molecular spectroscopy: so it was a nice conflation of an idea from one discipline and experimental developments from another. Why did you name C60 after the architect R. Buckminster Fuller? When we had the evidence for a 60 carbon atom species we had to think about how or what it might be. We knew (everybody knew!), that graphite tends to form sheets of carbon atoms in hexagonal arrays and we wondered if the sheets might close with a hexagonal cage involving 60 carbon atoms. I’d been to Expo ’67 (the World’s Fair in Montreal, Canada) and had seen Buckminster Fuller’s dome and in fact I had the graphic art magazine called Graphis with the picture of the geodesic dome in it that I’d looked at numerous times because I’d been to that exibition—I had even taken a movie at Expo ’67. In fact many years earlier, before I was offered the permanent position at Sussex, I had been thinking about getting a job with Buckminster Fuller to study the way in which cities developed. He had quite a number of interesting research projects. One of them involved ideas about how cities grew. I had also made a stardome (which is a map of the sky) that turned out to be a truncated icosahedron. During our discussion on what the C60 cluster might be, we thought that maybe the hexagonal sheet curled into a closed ball in some way and that might explain why it was stable and fairly unreactive. Buckminster Fuller’s ideas were part of the thinking process and when we came to the conclusion that it might be a geodesic dome, I suggested that we should call it after Buckminster Fuller. In fullerene the -ene ending is perfect for a sheet molecule with double bonds. Benzene is a six membered ring with three double bonds, naphthalene has two rings, three in anthracene, and Buckminsterfullerene seemed to me to be a nice name, although it was a bit long (5). Reading the papers you wrote before there was X-ray evidence (6–12), it was astonishing how strong your faith in the closed structure was. Did your love for the design help you foresee the correct structure? I think all scientists who are successful find beauty in patterns, either in numbers or in spatial symmetries. They look for the way things fit into place in some beautiful patterns. I think when we came to the conclusion that the C60 molecule might be a beautifully symmetric soccerball structure with twelve pentagons and twenty hexagons I think we were all, from the first moment, fairly convinced that we must be right. I think afterwards we probably had the odd thought that maybe there were other solutions but, basically I think the fact that it was such a beautiful and elegant structure was very convincing. I’m particularly visually oriented, I like visual
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patterns and not necessarily just symmetric ones. I particularly like graphic art, modern art, and asymmetry. I think you are right that it was important that it was an elegant structure. Later on I certainly had a few questions and used to go over them in my mind and think about the experiments we had done and all the evidence. In fact the crucial moment for me came when I realized that the first structure that could close without all the pentagons abutting was C60. That was an important moment because I realized that you need twelve pentagons to close any network of hexagons. You can’t do it with only hexagons. I then played around with the concept and conjectured that the second structure that could close was C70. Between 60 and 70 the network cannot close without putting two pentagons side-by-side: C70 was the next strong peak and so at that point I was absolutely convinced that we were right. As far as the structure is concerned I had three thoughts: one was that Buckminster Fuller’s geodesic dome might provide a clue, the second was the stardome I had made for my children some years before. It was a truncated icosahedron but at the time I could not quite remember it well though I knew that it had pentagons as well as hexagons. I didn’t know that there were pentagons in the geodesic dome. I also had another structure that wasn’t a closed sheet but also was a bit roundish, actually, a six-membered ring and then a seven ring structure, a sort of coronene structure, and then another coronene structure and then another six-membered ring. That gave the number sixty (six plus twenty-four plus twenty-four plus six). So I had three ideas. I considered calling my wife that night to find out whether the stardome that I had made for my children had sixty vertices but I didn’t do that as I was going home the next day and I was going to count it myself. By then Rick had tried to close a sheet of hexagons but he couldn’t do it. Then he remembered that I had suggested the pentagons and when he tried them he found that the structure closed up into the beautiful, elegant structure. When he brought the structure, a little paper model, in the next day, I was certainly ecstatic and I am sure the rest of us were, too. What about the Lone Ranger and Tonto1? Can there be an explanation for why C60 is always the dominant fullerene? I think C60 is the dominant structure because it’s the first one that can close without any of the twelve pentagons being adjacent (what we call abutting) and we know from organic chemistry and from our understanding of carbon chemistry that if you have two pentagons side by side that tends to be an unstable structure. So the first time a stable cage can form is for C60 (five times twelve is sixty). Research Trajectory You worked at the Algonquin Park radiotelescope and at Rice University. Before you won the Nobel Prize was it always easy for you to find money for your research work? I worked with Canadian astronomers and it’s also true that in the mid–seventies there were no telescopes in the UK that could do the radioastronomy experiments that I wanted to do. So I contacted my colleague at NRC, Takeshi Oka, and we joined up with the astronomers in Canada to do the experiments: they had the telescope and I didn’t actually need www.JCE.DivCHED.org
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much money. I made the lab measurements with my colleague David Walton, Anthony Alexander (a student at Sussex), and with the Canadian group and we found the first carbon chain molecule. Then we synthesized the next one and I went over to Canada. I got a NATO grant ($2000–3000 or so) to travel between the UK and Canada. So it wasn’t expensive because of course the telescope was already there and it was not difficult to convince the Canadians that this was an interesting project. As far as Rice is concerned, I just happened to be visiting and suggested the carbon vaporization experiment to Bob Curl and Rick Smalley. They thought they would fit it into one of their other projects, and when Bob telephoned me and said they were going to do it I decided to rush over to Rice University. That was in the late summer of 1985 and it just cost about £300. I stayed with Bob Curl and so the experiments “piggy–backed” on some experiments that they were doing on silicon and gallium arsenide. So, again it didn’t cost me too much, but of course it cost a lot to build the Rice apparatus in the first place. Actually the discovery experiment only took a week or so, and it just fitted into the experiments that were being carried out at Rice. I then actually got some money from EPSRC (Engineering and Physical Sciences Research Council) to go to Rice to follow up the discovery. This was travel money to go to Rice every six weeks or so for two or three years. That carried on for a year and a half to really test out our idea experimentally. Rice paid for my local expenses and, as I mentioned, the UK EPSRC paid my travel expenses and it all fitted into the experiments that were being carried out at Rice. Money for research is always difficult to come by. At the same time I had my own research programs in molecular spectroscopy—I always found money for research to be quite difficult to obtain. It took me from 1967 to 1974 to get my own microwave spectrometer in the first place. In 1974 (September or October) when I got it, I never looked back; that was the moment in which I was truly doing some very nice experimental work. I still had to get money for research, though in fact I always got graduates and they were covered by EPSRC. The microwave spectrometer worked continuously between 1974 and 1985, for eleven years. It was the bread-and-butter instrument for me until the C60 project came up. C60 is a “super alkene”, a precursor of many compounds. Could you mention some of the more interesting compounds and their applications? As far as C60 is concerned obviously its chemistry is very interesting. Halogenation studies (13) were carried out here by Paul Birkett who discovered that you can add six halogens to the surface of C60, or sometimes eight. In fact, also 24, so we and others found that there were certain patterns of the addition. Roger Taylor has been studying quite a lot of the synthetic aspects of C60 (14, 15). With David Walton I have been focusing more on the nanotechnology implications of the related nano tubes (16, 17). At this stage there are no applications that have really taken off: I think it is still quite early and it will be a long time before a molecule with such peculiar and novel behavior will find applications. There are lots of ideas, but at this stage I don’t think anyone has made any money out of C60. I think it will start to show some time
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soon, because there are interesting aspects of superconductivity and a wide range of other electronic and optical properties. Between the discovery of buckminsterfullerene and the conclusive proof of its structure by NMR, had there been moments of discomfort? How did you find the strength to continue? There were several papers that claimed we were wrong, yet as I said before, when I realized that C70 was the second magic fullerene I was totally convinced and I knew that one day we would be proved correct. That conviction occured maybe about six months to a year after the original discovery, so basically from 1986 or mid-1986 onwards; I never really had any doubt that the soccerball structure was correct. Research Funding Policies The political system exerts pressure for results on scientists in the applied sciences. You are a staunch defender of fundamental research in science. Why are politicians wrong? I think that basic scientists are much like children who are fascinated by things that they see and can’t understand. So the puzzle of finding out how things work is the main drive, the drive towards fundamental understanding. At the other end, of course, there is the drive to solve a problem and develop something that is of value. For instance, to make a faster processor in a computer or to store more information. In a sense it needs all facets of research strategy to improve existing technology. To discover new, totally unexpected processes, compounds, and effects is the basis of fundamental research. Somewhere in the middle, a connection between one and the other must be made. A favorite example is the invention of the laser: Charles Townes was interested in developing a high frequency amplifier and the laser was the result. He didn’t foresee the use of lasers in eye surgery. You could give all the money in the world to eye surgeons in 1950 but they would not have developed a laser—they couldn’t do it. So there’s a very nice example of why fundamental science should be supported and go hand-in-hand with applied research. Now I don’t actually believe our politicians are always getting it wrong; I think fundamental science is supported. CERN (Conseil Européenne pour la Recherche Nucléaire) is supported and that’s fairly fundamental and very expensive. It’s a case of getting the balance right and that is quite difficult because lay people don’t appreciate the intellectual and cultural aspect of science. In general they ask, what use is it? Only scientists really appreciate the intellectual aspect. I think it is like language; if you don’t understand Japanese then you can’t really understand the culture of Japan. If you can’t understand mathematics, chemical and physical symbolism, equations, these sort of things, then you really can’t understand the essence of science. Therefore the only thing that the average person who does not understand science can assess is the application. They can understand that. Science has three aspects: one is basically the knowledge that you learn at school, and then there are the applications of science, and then there is the intrinsic nature of the scientific process, how new science is discovered, finding things out, how research is done. These three aspects merge one into another, but they
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are somewhat different. The last one pertains to the fundamental scientist and that needs to be supported. I don’t think politicians get it wrong, per se; sometimes the balance is too far towards applications because that’s what concerns a politician. It’s the way in which money is spent and they want to show something directly to society that has been of use. With fundamental science it can take 50–100 years for an application to develop, whereas politicians are short-term people, they are around for three, four, five years and then they’re gone. Therefore, if you say liquid crystal research should be supported, in 1870 when Reinitzer made the first experiments it was very hard to foresee the applications in display circuits in the wristwatches of today. It’s that argument that we have to keep hammering away at. Teaching and Learning Science and Creativity Some instructors devote their life trying to improve their teaching. They work without any recognition, often treated as second-class citizens. Do you see any analogy with your work? In retrospect, how important a contribution did your education make to your subsequent successes? Is enthusiasm important in teaching, as it is in research? Well, it is certainly true that the enthusiasm of teachers is important. If you don’t have an enthusiastic teacher it may be difficult—yet enthusiasm is more subtle than most people realize. How a teacher interacts with a student is very subjective as far as the student is concerned. I found some teachers—whom other people didn’t like, didn’t find very interesting, or found boring—to be quite interesting to me. I understood what they were saying: again it’s like a language. If you can’t understand English then someone who’s speaking English cannot communicate with you. On the other hand, if you hope to develop an appreciation of what they think is interesting then you start to appreciate how their mind works and the sort of things that turn them on. So there is a big mistake, I believe, in trying to get people to jump around and get excited, to excite children: I think this is not the way. It’s very different from the way the average media person sees science education, often it should be quiet, careful interaction between the teacher and students. That is sometimes much more effective. So again it’s a one–to–one relationship. Some students learn better when excited and hooked in; others like to be very careful, and develop things themselves. I see that as a problem, because you just can’t have thirty different teachers for thirty different students. You usually get one teacher for thirty students. The students are all different, and so the teacher has to try as many different ways of teaching as possible, and this is rather difficult. Do you feel our present educational process is effective or must it be changed in order to foster more creative people? Could you give some suggestions? I don’t know how creative people develop their creativity. I think it requires education that is more subjective and fits around each individual who is quite different. I don’t think we have worked out how to do that yet and it’s very, very teacher intensive—one teacher per student—I don’t think we know really how to do it.
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Could you suggest how it is possible to get children more interested in science? Well, some children do get interested in science and technology somehow. I have often felt that in school, probably once a week, children should go back in time and spend a whole afternoon living as though they were in the 18th century so they can appreciate how many luxuries science and technology have made for them and try to see whether they can make some advances themselves. The problem is that technology today is so advanced that young children can’t actually understand how it works. In the past I think it was possible to see how some things actually worked: for example, with steam engines and locomotives you could see a little bit of how they worked, but electric motors are a bit more difficult and computers are essentially impossible. So, I think it is a slow process and children need to be given things that are actually working—not so much toys—rather, things that they can take apart and put back together and make them work again. Unfortunately, our modern society is so advanced that most things, once broken, have to be thrown away as they can’t easily be repaired. I see this as the major problem. In the past it was possible to repair almost anything. The repair process is a key aspect of learning how things work and thus also of scientific education. The Responsibilities of Scientists in Society You are much concerned about the “image” of the scientist in the society. What do you see the role of the scientist in society? They have to try to ensure that everybody understands and is aware of and appreciates what science has done for them. They must understand that we must make judicious decisions, careful decisions, and wise decisions. Scientific knowledge can be used either for the benefit of society or for ill and we as a society haven’t done very well in ensuring that science and technology are used for the benefit of the society. Scientists really must work over–time because the language of science is so complicated. Science and technology have freed society from the burden of working just to survive and I think that people in the latter part of the last century have forgotten this and it is a very serious problem. Life beyond Buckyballs In 1994 you won the prestigious Moët Hennessy–Louis Vuitton Science Pour L’Art prize, and you have so many scientific interests. What do you do in your spare time, for recreation? Unfortunately I have little spare time at the moment. I have to keep my research program going and my collegues at Sussex are, I think, fairly understanding about it. I am involved with the Vega Science Trust, which is trying to get scientists to make programs and broadcast them on the Internet as well as on television. My main interest in life actually is graphic art and design and one of these days I hope to get back to them since I feel they are an unfulfilled part of my life. I just didn’t expect that such a major discovery would arise and take over all my time as much as it has done.
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Some Final Words Harry Kroto creatively endeavors to undertake scientific research, increase public awareness and understanding of scientific issues, and to find more time for graphic art and design. Harry Kroto’s Web site, http://www.kroto.info/ (accessed Jan 2005), provides an overview of his scientific work and displays some of his art, as well. The links there will take interested visitors to additional information about Kroto’s projects and other related Web sites. Note 1. The Lone Ranger and Tonto were a famous American radio and television duo. Bob Dylan immortalized them in the following blues lyrics, cited in Kroto, H. W. Angew. Chem. Int. Ed. Engl. 1992, 31, 111–129. Well the Lone Ranger and Tonto They are ridin’ down the line Fixin’ ev’rybody’s troubles Ev’rybody’s ‘cept mine. Somebody must a tol’ ‘em that I was doin’ fine.
Literature Cited 1. The 1996 Nobel Prize in Chemistry. http://nobelprize.org/chemistry/laureates/1996/press.html (accessed Jan 2005). 2. Hopkinson, M. J.; Kroto, H. W.; Nixon, J. F.; Simmons, N. P. C. J. Chem. Soc. Chem. Commun. 1976, 13, 513–515. 3. Kroto, H. W. Nachr. Chem. Tech. Lab. 1982, 30, 765–770. 4. Kroto, H. W.; Heath, J. R.; O’Brien, S. C.; Curl, R. F.; Smalley, R. E. Nature (London) 1985, 318, 162–163. 5. Kroto, H. W. Nature (London) 1986, 322, 766. 6. Kroto, H. W. Nature (London) 1987, 329, 529–531. 7. Kroto, H. Science 1988, 242, 1139–1145. 8. Kroto, H. W.; McKay, K. Nature (London) 1988, 331, 328331. 9. Hare, J. P.; Dennis, T. J.; Kroto, H. W.; Taylor, R.; Wahab Allaf, A.; Balm, S.; Walton, D. R. M. J. Chem. Soc. Chem. Commun. 1991, 412–413. 10. Taylor, R.; Hare, J. P.; Abdul-Sada, A. K.; Kroto, H. W. J. Chem. Soc. Chem. Commun. 1990, 1423–1425. 11. Balm, S.; Wahab Allaf, A.; Kroto, H. W.; Murrell, J. N. J. Chem. Soc. Faraday Trans. 1991, 87, 803–806. 12. Meidine, M. F.; Hitchcock, P. B.; Kroto, H. W.; Taylor, R.; Walton, D. R. M. J. Chem. Soc. Chem. Commun. 1992, 20, 1534–1537. 13. Birkett, P. R.; Avent, A. G.; Darwish, A. D.; Kroto, H. W.; Taylor, R.; Walton, D. R. M. J. Chem. Soc. Chem. Commun. 1993, 15, 1230–1232. 14. Avent, A. G.; Birkett, P. R.; Kroto, H. W.; Taylor, R.; Walton, D. R. M. Chem.Commun. 1998, 19, 2153–2154. 15. Darwish, A. D.; Avent, A. G.; Birkett, P. R.; Kroto, H. W.; Taylor, R.; Walton, D. R. M. J. Chem. Soc. Perkin Trans. 2 2001, 7, 1038–1044. 16. Zhu, Y. Q.; Hsu, W. K.; Kroto, H. W.; Walton, D. R. M. Chem.Commun. 2001, 21, 2184–2185. 17. Zhu, Y. Q.; Sekine, T.; Brigatti, K. S.; Firth, S.; Tenne, R.; Rosentsveig, R.; Kroto, H. W.; Walton, D. R. M. J. Amer. Chem. Soc. 2003, 125, 1329–1333.
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