Characterization of citrates on gold and silver nanoparticles

Priastuti Wulandari, Takeshi Nagahiro, Nobuko Fukada, Yasuo Kimura, Michio Niwano, Kaoru Tamada

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)


In this paper, we report different coordinations of citrates on gold (AuNP) and silver (AgNP) nanoparticles, as determined using Fourier transform infrared spectroscopy (FTIR) and molecular orbital (MO) calculations. AuNPs and AgNPs are found to have completely different interactions with the carboxylate anchoring groups, as indicated by their unique asymmetric stretching vibrations in the FTIR spectra. The νas (COO-) of citrate exhibits a high-frequency shift resulting from the formation of a unidentate coordination on AuNPs, whereas this vibration exhibits a low-frequency shift as a result of ionic bond formation on AgNPs, as predicted from the MO calculations of the corresponding metal complex salts. The enhancement in the IR signals when their vibration direction was perpendicular to the nanoparticle surface revealed the influence of localized surface plasmons excited on the metal nanoparticles.

Original languageEnglish
Pages (from-to)244-248
Number of pages5
JournalJournal of Colloid And Interface Science
Publication statusPublished - Jan 5 2015

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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