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2007, 111, 7845-7847 Published on Web 05/15/2007
Biicosahedral Gold Clusters [Au25(PPh3)10(SCnH2n+1)5Cl2]2+ (n ) 2-18): A Stepping Stone to Cluster-Assembled Materials Yukatsu Shichibu,† Yuichi Negishi,† Takahito Watanabe,‡ Nirmalya K. Chaki,† Hiroyuki Kawaguchi,‡ and Tatsuya Tsukuda*,†,§ Department of Materials Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan, Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Yamate, Okazaki 444-8787, Japan, and CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan ReceiVed: April 23, 2007
The chemical reaction between [Au11(PPh3)8Cl2]+ and n-alkanethiol CnH2n+1SH (n ) 2, 8, 10, 12, 14, 16, and 18) serendipitously yielded stable Au25 cluster compounds with the formula, [Au25(PPh3)10(SCnH2n+1)5Cl2]2+. Single-crystal X-ray structural analysis of [Au25(PPh3)10(SC2H5)5Cl2](SbF6)2 revealed that the Au25 core is constructed by bridging two icosahedral Au13 clusters with thiolates sharing a vertex atom. Optical absorption spectroscopy showed that coupling between the Au13 building blocks gives rise to new electronic levels in addition to those of the Au13 constituents.
Introduction Extensive studies of small (
