The Art of Building Small: From Molecular Switches to Motors (Nobel Lecture)

Abstract

A journey into the nano-world: The ability to design, use and control motor-like functions at the molecular level sets the stage for numerous dynamic molecular systems. In his Nobel Lecture, B. L. Feringa describes the evolution of the field of molecular motors and explains how to program and control molecules by incorporating responsive and adaptive properties. At the start of my journey into the uncharted territory of synthetic molecular motors I consider it apt to emphasize the joy of discovery that I have experienced through synthetic chemistry. The molecular beauty, structural diversity and ingenious functions of the machinery of life,1, 2 which evolved from a remarkably limited repertoire of building blocks, offers a tremendous source of inspiration to the synthetic chemist entering the field of dynamic molecular systems. However, far beyond Nature's designs, the creative power of synthetic chemistry provides unlimited opportunities to realize our own molecular world as we experience every day with products ranging from the drugs to the displays that sustain modern society. In their practice of the art of building small, synthetic chemists have shown amazing successes in the total synthesis of natural products,3 the design of enantioselective catalysts4 and the assembly of functional materials,5 to mention but a few of the developments seen over the past decades. Beyond chemistry's contemporary frontiers, moving from molecules to dynamic molecular systems, the molecular explorer faces the fundamental challenge of how to control and use motion at the nano-scale.6 In considering our first successful, albeit primitive, steps in this endeavor, my thoughts often turn to the Wright brothers and their demonstration of a flying airplane at Kitty Hawk on the 17th of December 1903.7 Why does mankind need to fly? Why do we need molecular motors or machines? Nobody would have predicted that in the future one would build passenger planes each carrying several hundred people at close to the speed of sound between continents. While admiring the elegance of a flying bird, the materials and flying principle of the entirely artificial airplane is quintessentially distinct from Nature's designs. Despite the fabulous advances in science and engineering over the past century, manifested most clearly by modern aircraft, we are nevertheless humbled by the realization that we still cannot synthesize a bird, a single cell of the bird or even one of its complex biological machines. It is fascinating to realize that molecular motors are omnipresent in living systems and key to almost every essential process ranging from transport to cell division, muscle motion and the generation of the ATP that fuels life processes.8 In the macroscopic world it is hard to imagine daily life without our engines and machines, although drawing analogies between these mechanical machines and biological motors is largely inappropriate. In particular the effect of length scales should be emphasized when comparing for instance a robot in a car manufacturing plant and the biological robot ATPase. While in the first and are in the world of molecular machines dynamic In when at we beyond the to and the to control In the molecular world motion and that biological motors as the design of molecular systems with and motion is the the from molecules to dynamic molecular systems drawing from life challenge is to and motors are to dynamic and molecular systems from on key and dynamic and and molecular with a future responsive drugs and molecular machines In our to design molecules with the dynamic functions that evolved into molecular we inspiration from the process of amazing natural responsive process is on the a in the the of this process in the design of molecular and responsive in dynamic molecular systems and molecular be by and the use of distinct as it is a process with on by on on on and numerous molecules have in in our to responsive control of and of assembly and biolo