Picture of the Week: Olympicene
Olympicene, the smallest possible five-ringed structure - about 100,000 times thinner than a human hair - has been created and imaged by a collaboration of scientists between the Royal Society of Chemistry (RSC), the University of Warwick and IBM Research - Zurich. The researchers were able to bring a single molecule to life in a picture, using a combination of clever synthetic chemistry and state-of-the-art imaging techniques.
The scientists decided to make and visualise olympicene whose five-ringed structure was entered on ChemSpider, the RSC's free online chemical database of over 26 million records two years ago. Professor Graham Richards, an RSC Council member, considered a molecular structure with three hexagonal rings above two others to be an interesting synthetic challenge. He was wondering: could someone actually make it, and produce an image of the actual molecule?
Chemists at the University of Warwick, Dr David Fox and Anish Mistry, used some clever synthetic organic chemistry - the modern molecule designer's toolbox - to build olympicene. Alongside the scientific challenge involved in creating olympicene in a laboratory, there are some serious practical reasons for working with such a molecule.
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. For example these types of molecules may offer great potential for the next generation of solar cells and high-tech lighting sources such as LEDs. A first glimpse of the molecule's structure was obtained by Dr Giovanni Costantini and Ben Moreton at Warwick using scanning tunnelling microscopy.
A higher resolution technique was however needed to unravel its atomic-level anatomy.
To truly bring olympicene to life, the Physics of Nanoscale Systems Group at IBM Research - Zurich in Switzerland analyzed the chemical structure of olympicene with unprecedented resolution using a complex technique known as non-contact atomic force microscopy. Using the technique IBM scientists imaged a single olympicene molecule just 1.2 nanometres in width, about 100,000 times thinner than a human hair.
IBM scientist Dr Leo Gross explains that the key to achieving atomic resolution was an atomically sharp and defined tip apex as well as the very high stability of the system. The tip was prepared by deliberately picking up single atoms and molecules and it has been shown that it is the foremost tip atom or molecule that governs the contrast and resolution of our AFM measurements. This technique was first published in the journal of Science back in August 2009.