Taken from The Telegraph 21st September 2020
Malcolm Green, who has died aged 84, was Professor of Inorganic Chemistry at Oxford University, responsible for a wealth of contributions to organometallic chemistry – the study of compounds containing, and reactions involving, metal-carbon bonds. Green was the recipient of many honours and awards, inspiring a generation of chemists.
He was a co-founder in 2006 of the Oxford Catalysts Group (later renamed Velocys), where catalysts are the lifeblood of the chemical industry, speeding chemical reactions to make fuels, plastics, drugs and much more.
Chemistry can be viewed as glorified Lego, with chemists assembling atoms, catalysts providing them with the means to assemble them efficiently and in new ways. An iconoclast, Green devised methods to unite metals with hydrocarbons – endless confections of hydrogen and carbon atoms typically from fossil fuels – to create “organometallic” compounds and a vast menagerie of useful chemicals.
Malcolm Leslie Hodder Green, the son of Leslie Ernest Green and Sheila Ethel (née Hodder), was born at Eastleigh, Hampshire, on April 16 1936. His father was a GP, and he had an elder sister, Silvia.
His parents divorced, and young Malcolm was sent to board at Smallwood Manor, the prep school for Denstone College in Staffordshire, then an independent boarding school founded on Christian principles by Nathaniel Woodard.
His mother insisted that he leave school and begin earning in what would have been his last year there, so he applied for a job at ICI. But the alert scientist who interviewed him told him to get a degree instead, and so he took his BSc at neighbouring Acton Technical College in 1956.
Green completed his PhD in 1959, supervised by Professor Sir Geoffrey Wilkinson. His passion for organometallic chemistry, and its potential in catalysis, had been ignited when he joined Wilkinson’s research group at Imperial College.
Wilkinson had recently returned from Harvard, where he had done research that would lead to a share of a Nobel prize in 1973, for creating molecules not found in nature – ferrocene, like a jam sandwich where the slices of bread are two molecules, each consisting of a ring of carbon atoms linked to hydrogen atoms, and the jam was an iron atom.
Inspired by Wilkinson and the potential of organometallic chemistry, Green set out on his own at Cambridge. With his long hair and a gung-ho attitude that he transmitted to many of his students, his messy laboratory was aptly christened “the jungle”.
His three years there, as a lecturer and Fellow of Corpus Christi College, established his reputation for creativity in making new sandwich molecules, and the pace increased when he moved to Oxford in 1963 as a Septcentenary Fellow of Inorganic Chemistry at Balliol College.
Seeing an opportunity in the work of Peter Timms at Bristol, Green and his students extended and developed a powerful way to assemble molecular “sandwiches” known as metal vapour synthesis. In the technique, metal vaporised under high vacuum was fired at a layer of frozen “bread” molecules.
This apparently brute force method – that relied on powerful vacuum pumps, gallons of liquid nitrogen, vast glass bell jars, and metals evaporated at searing temperatures of 3,500C – would prove an astonishingly delicate way to make a menagerie of organometallic molecules which, until then, had been thought impossible to create in the laboratory.
That work inevitably touched on one of the great challenges of the 1980s. It was difficult to do much more with hydrocarbons of the petrochemical industry than burn them. Chemists wanted to find a way to take boring and ubiquitous carbon-hydrogen bonds and “activate” them, so the colossal range of hydrocarbon molecules could be linked together and transformed gently into valuable feedstocks for fine chemicals.
In the 1960s there had begun to be hints that the bonds between specific carbon and hydrogen atoms could be broken selectively using transition metal compounds and Green, harnessing his skills at making organometallics, was well placed to build on this insight.
Handling such reactive species was not for the faint-hearted and required exceptional experimental skills along with a fairly robust attitude to risk. After one fire in the lab, a fireman was heard to sigh: “Malcolm Green – explosion machine.”
As he and his students explored the chemistry of how metals interact with carbon-hydrogen bonds, Green identified a class of molecule in which a single C-H bond seemed to hang tantalisingly close, not quite bonded to and yet significantly weakened by, its proximity to a metal atom. His colleague at Balliol, the renowned classicist Jasper Griffin suggested the Homeric word “agostic” to describe these close-bonding interactions.
With Maurice Brookhart, Green correctly proposed that agostics might play a key role in the mechanism of the spectacularly efficient Ziegler-Natta catalysts that assemble smaller hydrocarbons into long chain-like molecules that are the basis of plastics (such as polyethylene and polypropylene) that we take for granted in our lives.
Green – who in 1989 was appointed Professor of Inorganic Chemistry, Head of the Inorganic Chemistry Laboratory and Fellow of St Catherine’s College, Oxford – always cast his net wide, looking at inserting metals into vast molecular layers, in so-called intercalation compounds, exploring the potential of new forms of carbon, notably “buckyballs” (football-shaped carbon confections), or filling tubes of carbon (nanotubes) with pure metal or with salts.
He was guided by an instinctive feeling for where the interesting chemistry was – guided by his wife, Professor Jennifer Bilham, after they married in 1965. She was a brilliant theoretician, who used spectroscopic and computational tools to unravel the detailed electronic structure of the compounds made in her husband’s group: the perfect scientific and romantic partnership.
Green had a bold insight that he would jokingly express as “to a first approximation all transition metals are the same”.
This instinct led him to a taxonomy of organometallic compounds by the “Covalent Bond Classification”, an elegant method for thinking about the way the electrons in a molecule are distributed between the metal and the carbon-containing fragments around it. Its simplicity and usefulness have led to its being widely adopted in undergraduate teaching across the world.
His pipe and especially his cigarette lighter travelled with him everywhere, including the lab, where he would sometimes try to coax reluctant chemistry by applying a small flame to the glassware, to the amusement – and despair – of his students.
His former student Andrea Sella recalled how, at a birthday party in later life, Green was presented with “Chairman Malcolm’s Little Green Book”, which documented his idiosyncratic attempts to break the chemical dogma of the day.
A large, warm, gregarious, good-humoured man, Malcolm Green loved watching and participating in sport, as well as entertaining family, friends and colleagues: he made parties fizz by leading songs at the piano, which he played entirely by ear.
He was also deft with his hands at drawing and painting, and making things, from furniture to his three children’s toys and Wendy house, as well as repairing anything from a computer to the piano bench, even building parts of the vast converted Warwickshire farmhouse and barn, cottages and stables in which he and Jenny lived after his retirement.
Keen on the garden and efficient in the kitchen garden, they treated their frequent guests to home-grown food and generous quantities of wine sourced from one or another of their college cellars.
In 2004 Green became an Emeritus Research Professor at Oxford. Green had held many visiting positions including Visiting Professor, Institut de Chimie des Substances Naturelles, Paris; Alfred P Sloan Visiting Professor, Harvard; Sherman Fairchild Visiting Scholar at the California Institute of Technology; and Walter Hieber Gast professor, University of Munich.
In his later years his health was poor, but that did not prevent him from rigging up computer services and sound, teaching his grandchildren to use their laptops and to trounce one another at croquet or table tennis.
Green was an inspirational, intuitive and brilliant chemist, and his laboratory was an exhilarating place in which to work. He left a deep impression on everyone who worked with him or knew him.
Malcolm Green is survived by his wife Jenny, two sons and a daughter.
Malcolm Green, born April 16 1936, died July 24 2020.
Rest in Peace.