Silver nanoparticles linked by a Pt-containing organometallic dithiol bridge: study of local structure and interface by XAFS and SR-XPS

Phys Chem Chem Phys. 2014 Jun 21;16(23):11719-28. doi: 10.1039/c4cp01264j. Epub 2014 May 9.

Abstract

Silver nanoparticles (AgNPs) functionalized with an organometallic bifunctional thiol containing Pt(ii) centers, generated in situ from trans-trans-[thioacetyl-bistributylphosphine-diethynylbiphenyl-diplatinum(ii)], were synthesized with different sulphur/metal molar ratios (i.e. AgNPs-1 and AgNPs-2) with the aim to obtain nanosystems of different mean size and self-organization behaviour. AgNPs spontaneously self-assemble, giving rise to 2D networks, as previously assessed. In this work a deeper insight into the chemico-physical properties of these AgNPs is proposed by means of synchrotron radiation induced X-ray photoelectron spectroscopy (SR-XPS) and X-ray absorption fine structure spectroscopy (XAFS) techniques. The results are discussed in order to probe the interaction at the interface between a noble metal and a thiol ligand at the atomic level and the aim of this study is to shed light on the chemical structure and self-organization details of nanosystems. The nature of the chemical interaction between the dithiol ligand and the Ag atoms on the nanoparticle surface was investigated by combining SR-XPS (S2p, Ag3d core levels) and XAS (S and Ag K-edges) analysis. UV-visible absorption and emission measurements were also carried out on all samples and compared with TD-DFT calculations so as to get a better understanding of their optical behavior and establish the nature of the excitation and emission processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Metal Nanoparticles / chemistry*
  • Molecular Structure
  • Organoplatinum Compounds / chemistry*
  • Photoelectron Spectroscopy
  • Quantum Theory
  • Silver / chemistry*
  • Sulfhydryl Compounds / chemistry*
  • Synchrotrons
  • X-Ray Absorption Spectroscopy

Substances

  • Organoplatinum Compounds
  • Sulfhydryl Compounds
  • Silver