Fraser Stoddart

Fraser Stoddart
Born	James Fraser Stoddart 24 5, 1942
Birthplace	Edinburgh, Scotland
Died	Template:Death date and age Melbourne, Australia
Nationality	British, American
Occupation	Chemist, academic
Known for	Design and synthesis of molecular machines, mechanically interlocked molecular architectures
Education	University of Edinburgh (BSc, PhD)
Children	2
Awards	Fellow of the Royal Society (1994) King Faisal International Prize in Science (2007) Nobel Prize in Chemistry (2016)

Sir James Fraser Stoddart (24 May 1942 – 30 December 2024) was a Scottish-born British-American chemist whose work in supramolecular chemistry and nanotechnology reshaped scientific understanding of how molecules can be designed to perform mechanical functions. Over a career spanning more than five decades, Stoddart developed methods for the efficient synthesis of mechanically interlocked molecular architectures—including catenanes, rotaxanes, and molecular Borromean rings—using principles of molecular recognition and molecular self-assembly. He demonstrated that these interlocking molecular structures could serve as molecular switches and laid the groundwork for their application in nanoelectronics and nanoelectromechanical systems. In 1991, he achieved the first synthesis of artificial molecular machines, a milestone that earned him a share of the 2016 Nobel Prize in Chemistry alongside Jean-Pierre Sauvage and Ben Feringa "for the design and synthesis of molecular machines." Stoddart held academic positions at several leading institutions, including the University of Sheffield, the University of Birmingham, the University of California, Los Angeles (UCLA), Northwestern University, and the University of Hong Kong. He was knighted in 2007 for his services to chemistry and molecular nanotechnology, and received numerous other distinctions including the King Faisal International Prize, election as a Fellow of the Royal Society, and membership in the German National Academy of Sciences Leopoldina and the Royal Netherlands Academy of Arts and Sciences.

Early Life

James Fraser Stoddart was born on 24 May 1942 in Edinburgh, Scotland. He grew up on a farm, an upbringing that has been noted as having instilled in him an early appreciation for the natural world and the processes underlying it. Stoddart went by the name Fraser throughout his life.

Details of Stoddart's childhood and family background in the public record are limited, though his Scottish roots remained an important part of his identity throughout his career. He was educated in Edinburgh and would go on to attend the University of Edinburgh for both his undergraduate and doctoral studies.

Education

Stoddart attended the University of Edinburgh, where he earned his Bachelor of Science degree. He remained at Edinburgh for his doctoral research, completing his first PhD thesis in 1966 under the supervision of Edmund Langley Hirst and Douglas M. W. Anderson. This thesis was titled "Studies on plant gums of the Acacia group" and focused on aspects of carbohydrate chemistry. Stoddart later completed a second doctoral thesis at Edinburgh in 1980, entitled "Some adventures in stereochemistry," reflecting his evolving research interests toward the three-dimensional spatial arrangement of atoms within molecules—work that would become foundational to his subsequent contributions to supramolecular chemistry.

His training in Edinburgh's chemistry department, particularly his grounding in organic chemistry and stereochemistry, provided the intellectual framework upon which he would build his career in the design and synthesis of complex molecular architectures.

Career

Early Academic Career

After completing his initial PhD in 1966, Stoddart pursued postdoctoral research and early academic appointments that broadened his scientific perspective. He held positions at several institutions in the United Kingdom before establishing himself as a leader in physical organic chemistry and what he would come to describe as "lock-and-key chemistry"—the study of how molecules recognise and bind to one another based on their complementary shapes.

Stoddart served on the faculty of the University of Sheffield and subsequently at the University of Birmingham, where he built research groups focused on the emerging field of supramolecular chemistry. During this period in the United Kingdom, he began the work on molecular recognition that would define his career, exploring how non-covalent interactions—such as hydrogen bonding and electrostatic forces—could be harnessed to create complex molecular assemblies.

Breakthrough in Molecular Machines

The central achievement of Stoddart's career was the development of methods to synthesise mechanically interlocked molecular architectures—molecules in which two or more components are linked not by chemical bonds but by mechanical entanglement. These structures include catenanes (interlocking molecular rings), rotaxanes (a molecular ring threaded onto a molecular axle, held in place by bulky stoppers), and molecular Borromean rings (three rings linked such that cutting any one frees the other two).

In 1991, Stoddart achieved the first synthesis of an artificial molecular machine—a rotaxane in which the ring component could be induced to shuttle between two positions along the axle, functioning as a molecular switch. This accomplishment was a landmark in the field. While Jean-Pierre Sauvage had previously demonstrated the synthesis of a catenane in 1983, Stoddart's innovation lay in showing that such interlocked structures could be designed to perform controlled, directional mechanical motion at the molecular level. The molecular shuttles and switches developed by the Stoddart group demonstrated that it was possible to create nanoscale analogues of macroscopic machines—devices that could be toggled between defined states by external stimuli such as changes in pH, light, or electrical potential.

These molecular machines represented a conceptual advance beyond traditional chemistry, which had focused primarily on forming and breaking covalent bonds. Stoddart's approach—which he sometimes termed "unnatural product synthesis" to distinguish it from the synthesis of naturally occurring molecules—exploited the principles of molecular self-assembly, in which molecules spontaneously organise into defined structures driven by non-covalent forces.

UCLA and Northwestern University

In 1997, Stoddart moved to the United States, joining the faculty of the University of California, Los Angeles (UCLA), where he served as the Saul Winstein Professor of Chemistry. At UCLA, Stoddart expanded his research programme, applying his molecular machines to practical problems in nanotechnology. He and his collaborators demonstrated that rotaxane-based molecular switches could be incorporated into electronic circuits, creating rudimentary nanoelectronic devices. His group also explored applications in nanoelectromechanical systems (NEMS), in which mechanical motion at the molecular scale could be converted into useful work or signal output.

In 2008, Stoddart moved to Northwestern University in Evanston, Illinois, where he was appointed Board of Trustees Professor of Chemistry. He led the Stoddart Mechanostereochemistry Group in the Department of Chemistry, which became one of the premier research groups in the world for the study of mechanically interlocked molecules and their applications. Under his direction, the group pursued an ambitious research agenda that encompassed the design of new molecular architectures, the development of molecular machines with increasingly sophisticated functions, and the exploration of applications ranging from drug delivery to materials science.

At Northwestern, Stoddart's group made significant contributions to a wide range of problems in supramolecular chemistry and molecular nanotechnology. The group published extensively, and Stoddart became one of the most cited chemists in the world.

University of Hong Kong

Later in his career, Stoddart also accepted an appointment as Chair Professor in Chemistry at the University of Hong Kong, reflecting the global scope of his academic engagements. He maintained affiliations with multiple institutions and continued to mentor students and postdoctoral researchers from around the world throughout his career.

Mentorship and Influence

Stoddart trained a large number of graduate students and postdoctoral researchers, many of whom went on to hold prominent academic positions. Among his notable students were David Leigh, who became a leading figure in the field of molecular machines in his own right, and Douglas Philp. The Stoddart Mechanostereochemistry Group served as a training ground for generations of chemists who carried the techniques and concepts developed by Stoddart into new areas of research.

Stoddart's influence extended beyond his direct mentees. His publications, lectures, and the visibility conferred by his awards helped to define supramolecular chemistry and molecular nanotechnology as mainstream fields within chemistry.

Personal Life

Stoddart held dual citizenship in the United Kingdom and the United States. He had two children. His wife, Norma Stoddart, was a significant presence in his life and career; in 2025, UCLA announced the establishment of the Fraser and Norma Stoddart Chair in Contemporary Chemistry, an endowed professorship honouring both Stoddarts.

Stoddart died on 30 December 2024 in Melbourne, Australia, at the age of 82. His death was mourned across the international chemistry community. Northwestern University, UCLA, and numerous other institutions issued tributes acknowledging his scientific contributions and his impact as a mentor.

Recognition

Throughout his career, Stoddart received a wide array of honours and awards that reflected the significance of his contributions to chemistry.

Nobel Prize in Chemistry

In 2016, Stoddart was awarded the Nobel Prize in Chemistry, shared with Jean-Pierre Sauvage and Ben Feringa, "for the design and synthesis of molecular machines." The Nobel Committee recognised that the three laureates had collectively developed molecules with controllable movements that could perform tasks when energy was added. Stoddart's specific contribution was acknowledged as the development of the rotaxane-based molecular shuttle and related mechanically interlocked architectures that could function as molecular switches and machines. At the time of the award, Stoddart was affiliated with Northwestern University.

Knighthood and National Honours

Stoddart was knighted in 2007 for his services to chemistry and molecular nanotechnology, receiving the honour from the British Crown. He was elected a Fellow of the Royal Society (FRS) in 1994, one of the highest honours available to scientists in the United Kingdom.

He was also elected a Foreign Member of the Royal Netherlands Academy of Arts and Sciences (KNAW). In addition, he was a member of the German National Academy of Sciences Leopoldina.

Major Scientific Awards

Stoddart received the King Faisal International Prize in Science in 2007, one of the most significant international awards in the sciences. He received the Arthur C. Cope Award from the American Chemical Society, one of the premier awards in organic chemistry. He had previously received the Arthur C. Cope Scholar Award from the same society.

In 2007, Stoddart was also a recipient of the Feynman Prize in Nanotechnology, awarded by the Foresight Institute for experimental work in nanotechnology.

He received the Royal Medal from the Royal Society of Edinburgh. Other honours included the Centenary Prize of the Royal Society of Chemistry (2014), the Nagoya Medal, and the Tetrahedron Prize for Creativity in Organic Chemistry from Elsevier.

Posthumous Honours

In 2025, UCLA posthumously awarded Stoddart the Glenn T. Seaborg Medal, and announced the creation of the Fraser and Norma Stoddart Chair in Contemporary Chemistry, with Osvaldo Gutierrez named as its inaugural holder.

Legacy

Stoddart's contributions to chemistry fundamentally expanded the scope of what chemists could achieve at the molecular level. By demonstrating that mechanically interlocked molecules could be designed, synthesised, and made to perform controllable mechanical functions, he helped establish the field of molecular machines as a distinct and productive area of scientific inquiry. The Nobel Committee's recognition in 2016 placed his work alongside that of Sauvage and Feringa as constituting the foundation of a new area of chemistry with far-reaching implications for technology and medicine.

The rotaxane-based molecular shuttles and switches developed by Stoddart's group became standard reference points in the literature of supramolecular chemistry. His synthesis of molecular Borromean rings was a particular tour de force, demonstrating a level of topological complexity in molecular design that had not previously been achieved. His work on molecular switches and their incorporation into nanoelectronic devices pointed toward potential applications in computing, sensing, and drug delivery—fields that continue to draw on the foundational concepts he established.

As a mentor, Stoddart trained a substantial number of researchers who went on to lead their own research groups around the world. His influence can be traced through the careers of scientists such as David Leigh, who has continued to advance the field of molecular machines, and through the broader community of chemists who were shaped by his publications and lectures.

The establishment of the Fraser and Norma Stoddart Chair at UCLA in 2025 reflected the enduring institutional recognition of his contributions to both science and academic life. Nature, in its obituary, noted the breadth and significance of the Stoddart group's contributions to chemistry and nanotechnology.

Stoddart's career exemplified the productive intersection of fundamental science and practical application. His insistence on rigorous molecular design, combined with a willingness to pursue ambitious and unconventional research goals, left a lasting mark on the discipline of chemistry and on the broader enterprise of nanotechnology.