Kroto, Sir Harold Walter [Harry]
- Anthony K. Cheetham
Kroto, Sir Harold Walter [Harry] (1939–2016), chemist, was born Harold Walter Krotoschiner on 7 October 1939 in Wisbech Nursing Home, 33 Lynn Road, Wisbech, Cambridgeshire, the son of Heinz Fritz Krotoschiner, later Kroto (1900–1977), novelty balloon manufacturer, and his wife, Edith Kathe Dora, née Worch (1902–1978). The family name was changed by deed poll in 1955.
Early life and marriage
Kroto’s parents were both German Jews, who had escaped Germany via the Netherlands in 1938. Kroto’s father then re-established his novelty balloon business in London, but on the outbreak of the Second World War he was interned, as an ‘enemy alien’, on the Isle of Man. Kroto’s by then heavily pregnant mother was evacuated to Wisbech, where Kroto was born, but she returned to London when he was three weeks old. The family’s address given on his birth certificate was 52 Upper Clapton Road, Clapton, London. However, his mother was evacuated a second time in 1940 and moved to Bolton, where Kroto’s father joined them on his release from internment. He retrained as a toolmaker, but later (in 1955) re-established once again his novelty balloon business. Kroto later acknowledged the influence of both parents—his father with his problem-solving skills, and his ‘extrovertly gregarious’ mother (autobiography, Nobel prize website).
Kroto, or Harry as he liked to be called throughout his life, was educated at Wolfenden Street School in Bolton and from 1947, as a scholar, at Bolton School, where he was a contemporary of the actor Ian McKellen and acted with him in a school production of Henry V (Henry was played by McKellen, the Duke of York by Kroto). They lost touch for many years, but became close friends later in life and McKellen spoke at Kroto’s funeral in 2016. Having been interested in science from an early age—besides his father, he credited Meccano both with sparking his interest and honing his skills—he was particularly influenced by two chemistry masters at Bolton School, Wilf Jary and Harry Heaney (who later became professor of organic chemistry at Loughborough University). On the latter’s advice (and having first been rejected by Cambridge, as he was always happy to point out), he went on to the University of Sheffield, where he was taught by Richard Dixon and John Murrell and graduated with a first-class BSc in chemistry in 1961. He stayed on to complete a PhD in molecular spectroscopy in 1964, with Dixon as his supervisor. His first two publications, in 1963 and 1965, were with Dixon, and reported the production of short-lived molecules using flash photolysis.
Kroto often talked of his prowess as a tennis player in his youth, and he represented both the university and the county during his years in Sheffield. He also had a flair for art and design, and was art editor of Arrows, the Sheffield University student magazine. His passion for art became a lifelong interest and he was very proud of winning the Moët Hennessy/Louis Vuitton Science pour l’art prize in 1994. He also designed the British postage stamp depicting chemistry for the centenary of the Nobel prizes in 2001 (printed in thermochromic ink) and his work was featured at the Royal Academy summer exhibition in 2004. He was particularly fond of designing logos and produced one for the International Center for Materials Research at the University of California, Santa Barbara, in 2004.
On 20 July 1963, at Sheffield register office, Kroto married Margaret Henrietta (Marg) Hunter (b. 1940), a fellow Sheffield graduate by then working as a vocational guidance officer (later as a careers information officer), daughter of Henry Mitchell Hunter, valuation officer. They had two sons, Stephen (b. 1966) and David (b. 1968), and were together for more than fifty years. During their long and happy marriage they travelled extensively together, especially after Kroto won the Nobel prize. Indeed, Marg used to maintain his diary and endeavoured to restrain him for making too many commitments.
From 1964 to 1966 Kroto was a postdoctoral fellow at the National Research Council of Canada in Ottawa, where he worked in the molecular spectroscopy laboratory led by Gerhard Herzberg (who won the Nobel prize for chemistry in 1971). There he worked closely, and formed lifelong friendships and collaborations with a group of highly talented scientists who included Alex E. Douglas, Takeshi Ora, Donald A. Ramsay, and James K. G. Watson, all future fellows of the Royal Society. Other important influences were Jon Hougen and Cecil C. Costain, in whose research group he worked on the microwave spectrum of cyanogen azide. In 1966–7 Kroto spent a further year in North America as a research scientist for Bell Telephone Laboratories, at Murray Hill, New Jersey, investigating liquid phase interactions by laser Raman spectroscopy.
Sussex and ‘buckyballs’
Kroto returned to the UK in 1967 to take up a post as tutorial fellow at the University of Sussex. He remained there until his formal retirement in 2004, first as a lecturer (1968–77), then as reader (1977–85), professor (1985–91 and 2001–04), and Royal Society research professor (1991–2001). His work at Sussex focused on microwave spectroscopy studies of the structure and bonding in small molecules of the non-metallic elements, often in collaboration with John Nixon and David Walton. These usually contained carbon in combination with other elements such as phosphorus and nitrogen, as well as hydrogen; typical examples include CF2=PH, CH3C=P, and H-C≡C-C≡C-C≡N. At first glance this line of research may seem rather esoteric and obscure, but Kroto’s interest in such molecules extended beyond the laboratory into the rarefied atmosphere of interstellar space, where there was spectroscopic evidence of small carbon-containing molecules related to the ones that he was studying in the laboratory. These were described in a series of papers, which were published by Kroto and his Canadian collaborators, such as Takeshi Oka, during the late 1970s in the prestigious Astrophysical Journal, concerning the detection of carbon-containing molecules such as HCnN, n = 5, 7, 9, in space. Indeed, Kroto wrote an important, single-author review on this subject entitled ‘Semistable molecules in the laboratory and in space’ in Chemical Society Reviews in 1982, three years before the discovery of the buckyball.
Kroto’s interest in the role of small carbon-containing molecules in interstellar space led him in 1985 to spend a sabbatical leave at Rice University in Houston, where he worked with Richard Smalley, Robert Curl, Jim Heath, and others using an instrument that had been developed in Smalley’s laboratory. The idea was simple, though the execution was quite challenging: to see what carbon species might be formed in the gas phase above a sample of graphite under irradiated by an intense, pulsed 532nm laser. The volatile carbon species were then identified by sweeping them into a mass spectrometer. It was anticipated that carbon chains might be formed, similar to the ones already observed by Kroto, but that idea turned out to be incorrect. Instead, the spectrum was dominated by one particular signal from a molecule of mass 720, corresponding to 60 carbon atoms. It seemed highly improbable that a chain of 60 carbon atoms would be particularly stable compared with other oligomers, and it was proposed instead that C60 was a spherical molecule with a structure containing 5- and 6-membered carbon rings, as described in a classical Nature paper by Kroto and others in 1985.
Kroto and his collaborators in Houston had discovered an entirely new form of carbon that was fundamentally different from the two well-known allotropes, diamond and graphite. It was given the name buckminsterfullerene, based on its broad similarity to the geodesic dome designed by the architect Buckinster Fuller at the 1967 Montreal World Fair. There seems little doubt that this appellation, which was later abbreviated to ‘buckyball’, was inspired by Kroto’s knowledge of design and his familiarity with Buckminster Fuller’s architectural work.
The proposed, ball-like structure of C60 was treated with scepticism by some members of the scientific community following the publication of the 1985 Nature paper, but the correctness of the model was unambiguously confirmed five years later when Wolfgang Krätschmer and Donald Huffman described a method by which bulk, polycrystalline samples of C60 could be produced by striking an arc between two carbon electrodes. The availability of bulk samples of C60 led to an explosion of work on its properties and potential uses, and it was investigated for applications ranging from superconductivity and solar cells to drug delivery and catalysis. It is probably fair to say that the practical utility of C60 has been disappointing. However, it was to play a much more important scientific role, because it could reasonably be argued that the discovery of C60 launched the nanotechnology revolution. In particular, during the thirty-five years since its discovery, nanomaterials of virtually every type of material—semiconductors, metals, ceramics, organics, and metal-organic frameworks—have been made and studied, and in the early twenty-first century these lie at the heart of many important nanotechnology devices and applications.
Another important chapter in the C60 story emerged in 2015, about a year before Kroto’s death. John Maier, an old friend of Kroto’s at the University of Basel, published a Nature paper in which he provided compelling spectroscopic evidence that C60 actually exists in interstellar space and is responsible for several of the dominant features observed in the so-called diffuse interstellar bands that are seen in spectra obtained from the Milky Way and other galaxies This exciting news was described in Kroto’s presence during a meeting at the Royal Society of Chemistry in Burlington House in May 2015 in celebration of the thirtieth anniversary of the discovery of the buckyball. Kroto was always the first to acknowledge that the identification of C60 was purely serendipitous because no one was expecting to find that particular molecule. However, Maier’s work confirms that Kroto’s original intuition—that something profound about the universe could be learned by studying gas phase carbon species in the laboratory—was indeed correct. This important validation of his life’s work gave Kroto great pleasure during the final year of his life.
Nobel prize and later research
Kroto shared the 1996 Nobel prize in chemistry with Curl and Smalley, in recognition of their discovery of buckminsterfullerene. Amazingly, the C60 work provided the springboard for two further sensational milestones in the chemistry of carbon. The first was the discovery of carbon nanotubes by Sumio Iijima in 1991, for which he received the Kavli prize in 2008 (though it is widely recognized that nanotubes were observed earlier than 1991 by Morinobu Endo in Japan). The second was the discovery of graphene—single sheets of carbon derived from graphite—by Andre Geim and Konstantin Novoselov in Manchester in 2004, for which they received the Nobel prize in physics in 2010. Who could possibly have imagined that three new forms of carbon would be found during the period 1985 to 2004?
In 2004, after reaching the official retirement age of sixty-five in a British university, Kroto found (inexplicably) that he was no longer needed at Sussex, so he took up the Frances Eppes chair at the department of chemistry and biochemistry at Florida State University. There he continued his work on nano-forms of carbon, especially on the mechanism of formation of carbon nanotubes. He continued to publish with collaborators at Sussex and elsewhere, and he made regular visits to Anthony Cheetham’s research group at the University of California, Santa Barbara, where the excellent electron microscopy facilities of the Materials Research Laboratory were used to characterize nanotube materials that were made by Mauricio Terrones and other co-workers in Sussex and elsewhere. In addition, Kroto developed an interest in metal organic frameworks and, in collaboration with Cheetham and colleagues at Florida State such as Naresh Dalal, used the National High Magnetic Field Laboratory in Tallahassee to study their ferroelectric and multiferroic properties. It gave him great pleasure that a paper on this topic in the Journal of the American Chemical Society (2009), with Cheetham, Dalal, and others, became one of his most highly-cited publications. In all, Kroto published almost 500 scientific papers, and one book, Molecular Rotation Spectra (1975, 2nd edn, 1983).
Public engagement and humanism
Kroto co-founded the Vega Science Trust with Patrick Reams (a BBC education producer) in 1994 to produce high-quality films about science for a general audience; he served as chairman thereafter and featured in four of the trust’s films. The trust closed in 2012, but the films remained available through its website, maintained by the University of Sheffield. Another aspect of Kroto’s deep interest in public engagement was his regular participation in ‘buckyball workshops’ for young schoolchildren, which were held in many locations around the globe. He ran several of these workshops at the University of California, Santa Barbara, often for schools where the first language was Spanish, and also ran a number of them overseas. A memorable one took place at the University of Zululand in Richards Bay, South Africa, in conjunction with a workshop on nanomaterials, where the young students were totally enchanted by Kroto’s presentation and active engagement in their efforts to build models of C60.
Kroto was raised by his parents in the Jewish faith, and later recalled that his conversion to atheism came when he ate croissants one Saturday while supposed to be fasting: ‘I waited for a 10 ton “Monty Python” weight to fall on my head! It didn’t’, he said (autobiography, Nobel prize website). Later he was a prominent supporter of the British Humanist Association, and was frequently involved in combatting religiously-based arguments in favour of creationism or against climate change science. ‘I am a devout atheist’, he said; ‘nothing else makes any sense to me and I must admit to being bewildered by those who, in the face of what appears so obvious, still believe in a mystical creator’ (ibid.).
Kroto continued to maintain a punishing schedule of public engagements almost to the end, despite suffering from motor neurone disease and being confined to a wheelchair. He also remained scientifically active, publishing his last journal papers in 2016.
Honours and wider interests
Kroto was a visiting professor at the University of British Columbia (1973), the University of Southern California (1981), the University of California, Los Angeles (1988–92), and the University of California at Santa Barbara (1996–2004). In addition to the Nobel prize, he received some forty-four honorary degrees, and was awarded the Longstaff medal of the Royal Society of Chemistry (1993), the Erasmus medal of the Academia Europaea (2002), and both the Michael Faraday prize (2001, awarded for public engagement) and the Copley medal (2004) of the Royal Society, among other honours. He was elected a fellow of the Royal Society in 1990 and knighted in 1996. He served as president of the Royal Society of Chemistry in 2002–04. Two buildings at the University of Sheffield were named after him, the Kroto Innovation Centre and the Kroto Research Institute.
In addition to his interest in tennis, Kroto was a lifelong fan, through thick and thin, of Bolton Wanderers Football Club. In politics he inclined to the left and was a strong supporter of Amnesty International. He was a man of principle, and returned honorary degrees from Hertfordshire and Exeter universities after they closed their chemistry departments.
Charismatic, full of energy and boyish enthusiasm, frequently with a grin, Harry Kroto had a zany sense of humour which colleagues on both sides of the Atlantic appreciated. Just a week before his death he was dissolving into laughter at John Cleese’s sketch about stupidity, one of his all-time favourites. He and his wife lived latterly in a sheltered housing complex in Lewes, Sussex. He died at St Peter and St James Hospice, in nearby North Chailey, of motor neurone disease on 30 April 2016. He was survived by his wife, Marg, and his sons Stephen, a film-maker and director, and David, a graphic artist. He was profoundly missed by his many friends worldwide, and will be remembered as one of the most creative scientific minds of the late twentieth and early twenty-first centuries.
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- WW (2016)
- N. Sinclair, bromide print, 1997, NPG [see illus.]
- A. K. Purkiss, bromide prints, 1996, NPG
- J. F. Hunkin, colour print, 2001, NPG
- T. Barnes, oils, U. Sussex
- P. Edwards, portrait, 2010, priv. coll. [Kroto family; presented by University of Sheffield]
- photographs, The Kroto Research Institute, drive.google.com/file/d/0B3-cSaOqerotYVlkVDlJaVJOeWs/view, accessed 20 Aug 2019
- obituary photographs