Issue Date: February 25, 2008
Arthur C. Cope Award
How does a scientist prepare to work in the cutting-edge field of nanotechnology? For Sir Fraser Stoddart it was by milking cows, growing kale, and studying chemistry by the light of a kerosene lamp.
Stoddart grew up outside of Edinburgh, Scotland, on a tenant farm without electricity. He says he learned how to multitask by helping his parents care for livestock, by planting and harvesting crops, and by keeping the farm's machinery in working order. "I had a great opportunity to do what is probably not possible for young people to do today, in terms of stripping machines down and putting them back together again," Stoddart recalls. "It was an enormous source of satisfaction for me."
An only child, Stoddart was often without playmates and had to amuse himself with solitary pursuits. "I was addicted to solving jigsaw puzzles," he recalls. "It's said that I used to snatch the pieces out of adults' hands as they were contemplating where they might go. Amusingly, now I find that my grandson does the same with me."
The mechanical tinkering and jigsaw-puzzle expertise of his youth would later inspire Stoddart to create the mechanically interlocked molecules and molecular machinery for which he has become world-renowned. He is being honored for the development of chemistry of the mechanical bond and for exploiting its use in template-directed synthesis of molecular machines and switches.
It was chemistry's intellectual rigor that first attracted Stoddart to the field. He recalls a time during his days as an undergraduate at the University of Edinburgh when an analytical chemistry lecturer declared that no one had ever been able to finish all the experiments in his 10-week course. "To me that was like a red rag to a bull," Stoddart says. "So I used the knowledge of multitasking that I had learned on the farm, and I finished the experiments in seven weeks."
The lecturer was so impressed by the feat that he persuaded one of the university's professors to offer Stoddart a paid position working in the laboratory. It was there that chemistry's creative opportunities got Stoddart hooked on the discipline. "I realized chemistry would allow me to make things that nobody else had ever made," he says.
Stoddart earned a bachelor's degree from the University of Edinburgh in 1964. He stayed there to pursue his doctoral studies with Sir Edmund Hirst and D. M. W. Anderson, completing a Ph.D. in 1966. He then traveled to Queen's University, Kingston, Ontario, on a National Research Council of Canada postdoctoral fellowship. In 1970, he moved back to the U.K. as an Imperial Chemical Industries (ICI) research fellow at England's University of Sheffield. Shortly thereafter, he became a lecturer in its department of chemistry.
During the late 1970s and early 1980s, Stoddart took two sabbaticals from Sheffield. He spent three months at the University of California, Los Angeles (UCLA), interacting with the legendary physical organic chemist Donald J. Cram, and for three years, he worked at ICI's Corporate Laboratory in Runcorn, England. "It was the final days of corporate laboratories embracing basic research," he notes.
It was during his time at ICI that the seeds of Stoddart's next three decades of research were sown. "With my new colleagues in Runcorn, I did some shopping around in the basement and found a treasure chest full of transition-metal amines," Stoddart recalls. They were looking to see whether it was possible to complex these π-electron-deficient transition-metal amines with π-electron-rich crown ethers.
Indeed, these two kinds of molecules formed a supramolecular species. The result got the chemists thinking about using molecular recognition and self-assembly processes for making similar donor-acceptor complexes. "When we realized that we could also obtain good complexes between π-electron-rich crown ethers and the rodlike paraquat dication, we began to think of threading flexible macrocycles with rigid substrates," Stoddart says.
This thinking led Stoddart to make the first donor-acceptor catenane molecules, which feature a donor macrocycle mechanically interlocked with an acceptor one. Mechanically interlocked compounds known as rotaxanes followed shortly thereafter. "His work with supramolecular systems and the introduction of facile routes to molecular catenane and rotaxane structures changed the way chemists think about molecular systems," notes Chad A. Mirkin, a chemistry and materials science professor at Northwestern University.
In 1990, Stoddart and his group moved to England's University of Birmingham. There they began to transform these prototypical mechanically interlocked molecules into molecular machines and switches where the components move via chemical, electrochemical, or photochemical means. Using template-directed synthesis, they also continued to create increasingly complex molecular shuttles and bistable structures.
Stoddart moved again in 1997 to UCLA, where his group began to incorporate their molecular machines and switches into complex nanosystems and molecular electronics. "His work is responsible for putting chemists, synthetic organic ones in particular, at the forefront of the burgeoning field of nanoscience and nanotechnology," Mirkin says.
In 2003, Stoddart was named UCLA's Fred Kavli Chair in NanoSystems Sciences and became the director of the California NanoSystems Institute. "Stoddart has bridged the gap successfully between chemistry and the scientific and engineering challenges of nanoelectromechanical systems. He has introduced function into molecular nanotechnology," says David A. Leigh, one of Stoddart's former students who is now a chemistry professor at the University of Edinburgh.
To see the impact of Stoddart's research, one needs to look no further than his more than 800 publications. He is one of chemistry's most highly cited scientists, and he has won numerous awards, including the Nagoya Gold Medal in Organic Chemistry in 2004, the Albert Einstein World Prize in Science in 2007, and the King Faisal International Prize in Science in 2007. He was also appointed a Knight Bachelor last year by Queen Elizabeth II.
More than 300 graduate and postdoctoral students have studied under Stoddart's aegis, and he attributes much of his success to their creativity and hard work. He also recognizes the indispensable support of his late wife, Norma, and his daughters, Fiona and Alison.
"Stoddart has done what great chemists often do," Mirkin says. "He has effectively spanned many fields, built a program that is uniquely recognized as his, impacted and inspired several generations of scientists, and taken his discoveries from key fundamental observations to important technological advances."
At an age when most people would be settling into retirement, Stoddart, 65, has just started a new position as Northwestern University's Board of Trustees Professor of Chemistry. "I tell my group that our best work is still ahead of us," he tells C&EN. "We're going to pull up our socks and break new ground and go into new areas of science with a vengeance."
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