Molecular conformation changes in alkylthiol ligands as a function of size in gold nanoparticles: X-ray absorption studies

Journal Article · Tue Aug 15 04:00:00 EDT 2006 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.74.073410· OSTI ID:20853549

Ramallo-Lopez, J M; Giovanetti, L J; Requejo, F G ^[1]; Isaacs, S R; Shon, Y S ^[2]; Salmeron, M ^[3]

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1. Departamento Fisica FCE, Universidad Nacional de La Plata and IFLP-INIFTA (CONICET), 1900 La Plata (Argentina)
2. Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101 (United States)
3. Materials Science Division, Lawrence Berkeley National Laboratory, California 94720 (United States)

The bonding of hexanethiols to gold nanoparticles of 1.5, 2.0, and 3 nm was studied using x-ray absorption near-edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS). The XANES spectra revealed that a substantial fraction of weakly bound hexanethiol molecules are present in addition to those forming covalent bonds with Au atoms. The weakly bound molecules can be removed by washing in dichloromethane. After removal of the weakly bound molecules the S K-edge XANES reveals peaks due to S-Au and S-C bonds with intensities that change as a function of particle size. Au L{sub 3}-edge EXAFS results indicate that these changes follow the changes in coordination number of Au to the S atoms at the surface of the particles.

• OSTI ID: 20853549
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 7 Vol. 74; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTROSCOPY
ATOMS
CHEMICAL BONDS
COORDINATION NUMBER
COVALENCE
FINE STRUCTURE
GOLD
LIGANDS
METHYLENE CHLORIDE
MOLECULAR STRUCTURE
MOLECULES
NANOSTRUCTURES
PARTICLE SIZE
PARTICLES
X-RAY SPECTROSCOPY