Researchers Create And Image Smallest 5-Ring Molecule
May 28, 2012

Researchers Create And Image Smallest 5-Ring Molecule

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A collaboration of three groups is responsible for creating and imaging the smallest structure ever -- a billionth of a meter across and nearly 100,000 times thinner than a human hair.

The structure, called olympicene, because of its five-ringed shape being similar to that of the Olympic symbol, was first synthesized by University of Warwick, UK researchers, who worked closely with IBM Research - Zurich to bring the molecule to life, employing a combination of synthetic chemistry and high-tech imaging techniques. IBM Research pioneered the technique of single-molecule imaging with its non-contact atomic force microscopy in 2009.

The five-ringed molecule was entered on ChemSpider, the Royal Society of Chemistry´s (RSC) free online chemical database, which is comprised of more than 26 million records.

Though created by researchers at Warwick, the idea for the structure was actually conceived by RSC´s Professor Graham Richards CBE.

“When doodling in a planning meeting, it occurred to me that a molecular structure with three hexagonal rings above two others would make for an interesting synthetic challenge,” Richards told BBC News. “I wondered: could someone actually make it, and produce an image of the actual molecule?”

Working with Richards´ conception, Warwick´s Dr. David Fox and Anish Misry used clever synthetic organic chemistry to build the structure.

“Alongside the scientific challenge involved in creating olympicene in a laboratory, there's some serious practical reasons for working with molecules like this,” said Fox. “The compound is related to single-layer graphite, also known as graphene, and is one of a number of related compounds which potentially have interesting electronic and optical properties.”

Fox noted that the next generation of solar cells and high-tech lighting sources could excel with the aid of these types of molecules.

The structure of the molecule was first realized using scanning tunneling microscopy with the help of the university´s Dr. Giovanni Costantini and Ben Moreton. However, a higher resolution technique was needed to work out the atomic-level anatomy of the structure.

To do this, IBM Research´s Physics of Nanoscale Systems Group in Switzerland analyzed the olympicene using non-contact atomic force microscopy. Employing the technique IBM scientists imaged a single olympicene molecule one billionth of a meter in width (1.2 nanometers).

“The key to achieving atomic resolution was an atomically sharp and defined tip apex as well as the very high stability of the system,” explained IBM scientist Dr. Leo Gross. “We prepared our tip by deliberately picking up single atoms and molecules and showed that it is the foremost tip atom or molecule that governs the contrast and resolution of our AFM measurements.”

Professor Richards is hopeful that olympicene´s greatest contribution to chemistry is to encourage more students to become interested in chemistry and science.

“Molecules of this nature could conceivably have commercial use, but my own feeling is that above all we want to excite an interest in chemistry provoked by the link with the Olympics,” he said.