‘Iron sandwich’ might enable future electronic devices

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Scientists have created ring structure based on iron molecules and say it could be used for new applications in electronics and sensing. The work is based on ferrocene, a molecule discovered in the 1950s. This comprises two rings of hydrogen and carbon bound to either side of an iron atom.

Working with a team from the University of Konstanz, researchers from Imperial College London have created a series of rings containing ferrocene molecules linked directly to create a molecular ‘daisy chain’.

When the team investigated the way in which electrical charge is handled by the rings, it discovered that interactions between individual ferrocene units resulted in an unusual charging behaviour of the entire ring.

Adjusting the charge on one ferrocene unit causes the other units in the ring to re-arrange their charges without transferring the charge itself. This would avoid heating the molecules as the charge passes through, as happens with conventional electronics. This is said to be similar to the way in which some small metal nanoparticles behave. The properties of these nanoparticles mean they are being investigated for use as ‘molecular switches’.

Researchers Professor Nicholas Long and Dr Tim Albrecht, from Imperial’s Department of Chemistry, said: “We see applications of these ferrocene ring systems in memory or switching devices. When we manufacture ferrocene rings they are all identical, as opposed to some existing nanomaterials.

“This would make them much better candidates for molecular switches in computing, as the way they react to different charges would be exactly the same each time.”

The study’s first author Dr Michael Inkpen added: “Given that there has now been more than 60 years of research into sandwich compounds, it was thrilling to uncover a new family of ferrocene based materials with such remarkable properties. Whilst they are structurally quite simple, to the eye of a chemist they appear rather beautiful.”

The researchers will now continue to investigate the electrical properties of the ring structures and how they might be used in computers.