Synthesis and Electrochemical and Spectroscopic Characterization of Biicosahedral Au25 Clusters
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- 作者：SunYoung Park ; Dongil Lee
- 刊名：Langmuir
- 出版年：2012
- 出版时间：May 1, 2012
- 年：2012
- 卷：28
- 期：17
- 页码：7049-7054
- 全文大小：283K
- 年卷期：v.28,no.17(May 1, 2012)
- ISSN：1520-5827
文摘
The synthesis and electrochemical and spectroscopic characterization of biicosahedral Au25 clusters with a composition of [Au25(PPh3)10(thiolate)5Cl2]2+ are described. The biicosahedral Au25 clusters protected with various types of thiol ligands including alkanethiols, 2-phenylethanethiol, 11-mercaptoundecanoic acid, and 11-mercapto-1-undecanol were synthesized in high yields using a one-step, one-phase procedure in which Au(PPh3)Cl is reduced with tert-butylamine鈥揵orane in the presence of the thiol ligand in a 3:1 v/v chloroform/ethanol solution. All biicosahedral Au25 clusters prepared exhibit characteristic optical absorption and photoluminescence properties. The emission energy is found to be substantially smaller than the optical absorption energy gap of 1.82 eV, indicating a subgap energy luminescence. The electrochemical HOMO鈥揕UMO gap (1.54 eV) of the clusters is also substantially smaller than the optical absorption energy gap but rather similar to the emission energy. These electrochemical and optical properties of the biicosahedral Au25 clusters are distinctly different from those of the Au25(thiolate)18 clusters.