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Electron transfer in peptides: on the formation of silver nanoparticles

  • Kracht, Sonja Department of Chemistry, University of Fribourg, Switzerland
  • Messerer, Matthias Department of Chemistry, University of Fribourg, Switzerland
  • Lang, Matthieu Department of Chemistry, University of Fribourg, Switzerland
  • Eckhardt, Sonja Department of Chemistry, University of Fribourg, Switzerland
  • Lauz, Miriam Department of Chemistry, University of Fribourg, Switzerland
  • Grobéty, Bernard Department of Geoscience, University of Fribourg, Switzerland
  • Fromm, Katharina M. Department of Chemistry, University of Fribourg, Switzerland
  • Giese, Bernd Department of Chemistry, University of Fribourg, Switzerland
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    02.03.2015
Published in:
  • Angewandte Chemie International Edition. - 2015, vol. 54, no. 10, p. 2912–2916
English Some microorganisms perform anaerobic mineral respiration by reducing metal ions to metal nanoparticles, using peptide aggregates as medium for electron transfer (ET). Such a reaction type is investigated here with model peptides and silver as the metal. Surprisingly, Ag⁺ ions bound by peptides with histidine as the Ag⁺-binding amino acid and tyrosine as photoinducible electron donor cannot be reduced to Ag nanoparticles (AgNPs) under ET conditions because the peptide prevents the aggregation of Ag atoms to form AgNPs. Only in the presence of chloride ions, which generate AgCl microcrystals in the peptide matrix, does the synthesis of AgNPs occur. The reaction starts with the formation of 100 nm Ag@AgCl/peptide nanocomposites which are cleaved into 15 nm AgNPs. This defined transformation from large nanoparticles into small ones is in contrast to the usually observed Ostwald ripening processes and can be followed in detail by studying time-resolved UV/Vis spectra which exhibit an isosbestic point.
Faculty
Faculté des sciences et de médecine
Department
Département de Chimie, Département de Géosciences
Language
  • English
Classification
Chemistry
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/304198
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