Thiol-Terminated Di-, Tri-, and Tetraethylene Oxide Functionalized Gold Nanoparticles: A Water-Soluble, Charge-Neutral Cluster

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• 作者：Edward E. Foos ; Arthur W. Snow ; Mark E. Twigg ; and Mario G. Ancona
• 刊名：Chemistry of Materials
• 出版年：2002
• 出版时间：May 2002
• 年：2002
• 卷：14
• 期：5
• 页码：2401 - 2408
• 全文大小：202K
• 年卷期：v.14,no.5(May 2002)
• ISSN：1520-5002

文摘

A series of gold nanoclusters stabilized by ligands containing short ethylene oxide oligomersof fixed length were prepared and characterized. The thiols CH₃(OCH₂CH₂)_nSH (where n =2, 3, and 4) were substituted onto the surface of 1.8-nm hexanethiol-capped gold clusters bya thiol-exchange reaction, and the resulting nanoclusters were characterized by NMR, FTIR,and UV/vis spectroscopies; TGA; and TEM analysis. A degree of ligand exchange greaterthan 99% was achieved, and the gold core diameter remained unchanged in the final material.Of particular interest, the cluster with n = 2 was water-insoluble, whereas those with n =3 or 4 were water-soluble. The thin-film electrical conductivities of these clusters werecompared with those of alkanethiol-capped clusters of similar chain lengths and found to beroughly 1 order of magnitude greater. In a chemical vapor sensor configuration, this seriesof clusters displayed strong electrical responses that showed a correlation between the lengthof the ethylene oxide ligand and the polarity of the vapor.