Illustration of the British-US chemist J. Fraser Stoddart (born 1942). Stoddart is best know for his pioneering work in molecular machines, small organic molecules that move in response to a stimulus. He was the first, in the mid 1980s, to synthesise a catenane, a type of mechanically-interlocked molecular architecture composed of two interlocked macrocycles (molecular rings). Then in 1991 he synthesised a rotaxane, a type of molecular switch consisting of a macrocycle that was able to move up and down a dumbbell-shaped molecule. Catenanes and rotaxanes are joined by mechanical, rather than chemical, bonds, allowing movement of the bonds relative to each other. Stoddart, shared the 2016 Nobel Prize in Chemistry for this work with Jean-Pierre Sauvage and Bernard Feringa.