Professor Sir J. Fraser Stoddart (✝︎)

Research Priorities: Supramolecular chemistry, physical organic chemistry, stereochemistry, molecular machines
Sir J. Fraser Stoddart was a British-American chemist. His research focus was on the synthesis of molecular machines that consist of molecules, which can fulfil mechanical functions. For example, a molecular switch can be turned on and off again via external stimuli like light, electrical, or magnetic fields. Fraser Stoddart’s research at the nanoscale has enormous potential for the development of new materials and appliances. In 2016, he was awarded the Nobel prize for chemistry together with the Dutch physicist Bernhard L. Feringa and the French chemist Jean-Pierre Sauvage.
In Nature, molecular machines are nothing new, but they are in chemistry. Biological systems like enzymes and proteins turn chemical energy into mechanical energy. The most famous example of a natural molecular machine is adenosine triphosphate (ATP) -synthase. It produces ATP, which is the molecule that provides energy to the metabolism of living cells. In contrast to their natural models, the tiny molecular compounds, which are produced in the laboratory, are deliberately programmed and steered to fulfil specific tasks. 
Building on the work of Jean-Pierre Sauvage, Fraser Stoddart worked towards developing molecular engines that perform rotating motions, not unlike the engine of a car. These engines, which are called rotaxanes, consist of multiple interconnected molecules that are arranged in a covalent network. By applying external forces, these molecules can turn in a certain direction and thus move.
Fraser Stoddart and his team focused on producing these machines through complex, multistage processes of synthesis. Among other things, they developed molecular Borromean rings, that consist of multiple interwoven circular molecules, during this process. If one of these rings is removed, all other rings disintegrate. Producing Borromean rings is a challenge because of the difficulties in weaving the three rings together so that they remain stable. In 1994, Fraser Stoddart developed the first Borromean ring from molecular building blocks and called it “Molecular Borromean Linkage”. 
Borromean rings bear great potential for the development of molecular machines as they can execute precise functions because of their complex and nonlinear structure. Fraser Stoddart and his team developed for example an artificial molecular muscle, which consists of Borromean rings. This special molecular machine can move by activating and deactivating specific chemical reactions.
Fraser Stoddart was awarded multiple awards for his work, amongst them the Nobel prize in chemistry in 2016. His work bears the potential to develop new materials and applications that can be controlled on a molecular level. Possible fields of application lie in medicine, electronics and energy production. As a renowned chemist, he significantly contributed to the theoretical advancement of supramolecular chemistry.