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Au40(SR)24 Cluster as a Chiral Dimer of 8-Electron Superatoms: Structure and Optical Properties

Malola, Sami
Lehtovaara, Lauri
Hu, Kuo-Juei
Palmer, Richard E.
Häkkinen, Hannu
Published in Journal of the American Chemical Society. 2012, vol. 134, no. 48, p. 19560-19563
Abstract We predict and analyze density-functional theory (DFT) -based structures for the recently isolated Au40(SR)24 cluster. Combining structural information extracted from ligand-exchange reactions, circular dichroism and transmission electron microscopy leads us to propose two families of low-energy structures that have a chiral Au-S framework on the surface. These families have a common geometrical motif where a non-chiral Au26 bi-icosahedral cluster core is protected by 6 RS-Au-SR and 4 RS-Au-SR-Au-SR oligomeric units, analogously to the “Divide and Protect” motif of known clusters Au25(SR)18-/0, Au38(SR)24 and Au102(SR)44. The strongly prolate shape of the proposed Au26 core is supported by transmission electron microscopy. Density-of-state-analysis shows that the electronic structure of Au40(SR)24 can be interpreted in terms of a dimer of two 8-electron superatoms, where the 8 shell electrons are localized at the two icosahedral halves of the metal core. The calculated optical and chiroptical characteristics of the optimal chiral structure are in a fair agreement with the reported data for Au40(SR)24.
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Research group Groupe Bürgi
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MALOLA, Sami et al. Au40(SR)24 Cluster as a Chiral Dimer of 8-Electron Superatoms: Structure and Optical Properties. In: Journal of the American Chemical Society, 2012, vol. 134, n° 48, p. 19560-19563. https://archive-ouverte.unige.ch/unige:24516

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Deposited on : 2012-12-12

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