New way to control chemical reactions
Scientists have used electric currents to control chemical reactions in a completely new way, in a breakthrough that could have implications for how chemicals are made in the future.
Professor Michelle Coote, a theoretical chemist from the Australian National University worked with researchers from the University of Wollongong and the University of Barcelona to see if an electric current could catalyse a common chemical reaction.
Professor Coote said the team had overturned conventional thinking with their new-found control of the common reaction, which is used to make a range of chemicals from self-healing materials to the drug cortisone. By using numerical modelling on the NCI supercomputer to inform their experimental design, the team managed to produce a previously unknown result.
“It’s the most unexpected result possible,” said Professor Coote who is also a Chief Investigator with the ARC Centre of Excellence for Electromaterials Science (ACES). “We now have a totally new way of thinking about chemistry.”
“The breakthrough could speed up manufacturing processes and allow unprecedented control of chemical reactions, for example in manufacturing flexible electronic components based on organic circuits,” she said.
Theoreticians had predicted that electric fields could strongly affect reaction rates, but it had never been observed before because standard chemical reactions are conducted with molecules oriented in random directions in a gas or liquid. The collaboration of scientists devised a way to test the prediction with a new method.
Using the electric field generated by the tip of a scanning-tunneling electron microscope, the group oriented all the molecules in the same direction. They could then use the probe of the microscope to test each molecule at a variety of different voltages.
By changing the strength and polarity of the electric field, the team were able to vary the rate of the reaction, called a Diels-Alder reaction, by a factor of five. Professor Coote’s team used quantum chemical calculations, carried out using the NCI National Facility, to confirm that the results observed were due to the effects of electric fields.
ACES Director Professor Gordon Wallace said it is only a holistic approach to interdisciplinary research that can take ideas to industries in the shortest time possible. “The collegial environment and multidisciplinary approach within ACES meant that we could mobilise all the skills necessary—from molecular modelling to exquisite experiments—very quickly to enable this amazing discovery,” Professor Wallace said.
The breakthrough was supported by NCI through the National Computational Merit Allocation Scheme and has been published in the latest edition of Nature.