X-ray Crystal Structure and Theoretical Analysis of Au25-xAgx(SCH2CH2Ph)18- Alloy

被引:201
|
作者
Kumara, Chanaka [1 ]
Aikens, Christine M. [2 ]
Dass, Amala [1 ]
机构
[1] Univ Mississippi, Dept Chem & Biochem, Oxford, MS 38677 USA
[2] Kansas State Univ, Dept Chem, Manhattan, KS 66506 USA
来源
基金
美国国家科学基金会;
关键词
OPTICAL-ABSORPTION SPECTRA; PROTECTED AU-25; ELECTRONIC-STRUCTURE; NANOPARTICLES; CLUSTERS;
D O I
10.1021/jz402441d
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The atomic arrangement of Au and Ag atoms in Au25-xAgx(SR)(18) was determined by X-ray crystallography. Ag atoms were selectively incorporated in the 12 vertices of the icosahedral core. The central atom and the metal atoms in the six [-SR-Au-SR-Au-SR-] units were exclusively gold, with 100% Au occupancy. The composition of the crystals determined by X-ray crystallography was Au18.3Ag6.7(SCH2CH2Ph)(18). This composition is in reasonable agreement with the composition Au18.8Ag6.2(SCH2CH2Ph)(18) measured by electrospray mass spectrometry. The structure can be described in terms of shells as Au-1@Au5.3Ag6.7@6X[-SR-Au-SR-Au-SR-]. Density functional theory calculations show that the electronic structure and optical absorption spectra are sensitive to the silver atom arrangement within the nanocluster.
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页码:461 / 466
页数:6
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