X-ray Crystal Structure and Theoretical Analysis of Au25-xAgx(SCH2CH2Ph)18(-) Alloy.
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 Au1@Au5.3Ag6.7@6×[-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.
†Department of Chemistry and Biochemistry, University of Mississippi, Oxford, Mississippi 38677, United States.
Chanaka
C
Kumara
§Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States.
Christine M
CM
Aikens
†Department of Chemistry and Biochemistry, University of Mississippi, Oxford, Mississippi 38677, United States.
Amala
A
Dass
Au25; alloy nanomolecules; gold−silver alloy; monolayer protected clusters