The theoretical structure was confirmed via comparison to experimental results obtained by X-ray diffraction from powder samples of the pure cluster material. The theoretical work was done in collaboration with researchers at Kansas State University and the experimental part at Hokkaido University. The team is supported by the Academy of Finland and the CSC – the IT Center for Science.
The synthesis of organothiolate-protected gold clusters of 1 to 3 nm in size has been well known since the mid-1990s, but the detailed atomic structure of the most stable clusters remained a mystery until very recently. In 2007, the structure of the first cluster that contained 102 gold atoms was resolved at Stanford University using single-crystal X-ray crystallography. The cluster now resolved has exactly 38 gold atoms and 24 organothiolate molecules covering its surface and it is just about one nanometer (nanometer = one millionth of a millimeter) in size. The shape of the particle is prolate (cigar-like), and 15 out if its 38 gold atoms reside on the protective surface layer chemically bound with the thiolate molecules. The gold-thiolate layer has a chiral structure, which is responsible for the observed chiral properties. The chiral structure has two structural forms (enantiomers), the so-called right-handed and left-handed forms, in a way comparable to a twist in a DNA molecule or to a twist in the staircase structure of a block of flats.
Chirality is a very common structural property of molecules in nature. The chiral nature of gold clusters influences the way they respond to circularly polarised light. This effect was first reported in experiments by Professor Robert L. Whetten's team at Georgia Institute of Technology (Atlanta, USA) exactly ten years ago. "We observed that particularly the 38-atom cluster (for which no structural information was available) is very sensitive for the polarisation of light, and the now-resolved structure finally explains our observations," comments Professor Whetten. In the future, chiral gold nanoclusters could be used as bio-compatible, enantioselective sensors, drug carriers or catalysts.
Professor Häkkinen's team at the University of Jyväskylä has played a world-leading role in theoretical structural determination and characterisation of thiolate-protected gold nanoclusters over the last few years. The team has collaborated with researchers at Stanford University, Georgia Institute of Technology, Kansas State University, the University of North Carolina, Chalmers University of Technology and Hokkaido University.
For more information please contact Professor Hannu Häkkinen, email firstname.lastname@example.org, tel. +358 (0)14 260 4719
The study was published in the Journal of the American Chemical Society May 25, 2010. The link to the article "Chirality and electronic structure of the thiolate-protected Au38 nanocluster", O. Lopez-Acevedo, H. Tsunoyama, T. Tsukuda, H. Häkkinen, C.M. Aikens, JACS ASAP article May 25, 2010. http://pubs.acs.org/doi/abs/10.1021/ja102934q
Prof Hannu Häkkinen | EurekAlert!
What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering