Scientists rarely go straight for the target. An ode to the unexpected discoveries. Today: Organic chemist Ben Feringa on how a failed molecular switch opened the door to his Nobel Prize.

    Frank RensenSeptember 16, 202210:30

    ‘Science is an adventure: you go beyond the limits of knowledge, you walk off the known path. There you will come across surprising things, that is precisely the intention. Twenty years ago this also led me to be able to design the first molecular machines, such as a minuscule rotary engine, which we could later use to drive a car one millionth of a millimeter in size. That work earned me a nice medal in Stockholm, but the research is based on chance, an unexpected discovery.

    ‘At the time, I was doing research into molecular switches with my master’s and PhD students. These are switches as you know from your light switch or the on/off button on your laptop, but on a molecular scale. They can go one way or the other, a concept that’s behind information storage, in the zeros and ones that computers work with. With our molecular switches we were able to store information in plastics, like a kind of nano USB stick.

    ‘Our molecular switches could move through light energy. At first we mainly used blue light, because it carries a lot of energy. We were tinkering with the design of switches, for example to see if we could also make the switches work with other colors of light.

    ‘After some changes in the molecule of a certain switch, it wouldn’t switch back anymore. He did go, but not back. That was strange, we sat with our hands in our hair for a while. But guess what: instead of the switch turning 90 degrees and then back again, it turned another 90 degrees, making a total of 180 degrees. Then a light went on.

    ‘If such a switch can rotate 180 degrees, it may also be able to do it twice: a complete circle. We set to work on this, with the aim of making a rotating molecular wheel that could rotate with light energy. That worked, and that’s how the molecular motor was born. Finally, we were able to use this molecular technology to make a nano-car, with four-wheel drive.

    Ben FeringaStatue Stijntje de Olde

    ‘So what we wanted to achieve, a new molecular switch, had failed, but we found something much more beautiful. Designing these and other molecular machines even won me a Nobel Prize in 2016. We never stopped developing and improving molecular switches, so the molecular motor was really an additional discovery.

    ‘With science we look for the unexpected: you should ignore the questions to which you already know the answers. The best questions are those you don’t know exactly how to ask. So these kinds of accidental discoveries are part and parcel of the game: unexpected results are the most profitable. Provided you don’t push them aside, of course. The challenge is to recognize them among real failures.’

    Ben Feringa is professor of organic chemistry at the University of Groningen. In 2016, his work on molecular machines was awarded the Nobel Prize in Chemistry.