title: Silver nanoparticles linked by a Pt-containing organometallic dithiol bridge: study of local structure and interface by XAFS and SR-XPS.
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.
authors.affiliation: Roma Tre University, Department of Sciences and CISDiC, via della Vasca Navale 79, 00146 - Rome, Italy. chiara.battochio@uniroma3.it.
authors.forename: C
authors.initials: C
authors.lastname: Battocchio
authors.forename: I
authors.initials: I
authors.lastname: Fratoddi
authors.forename: L
authors.initials: L
authors.lastname: Fontana
authors.forename: E
authors.initials: E
authors.lastname: Bodo
authors.forename: F
authors.initials: F
authors.lastname: Porcaro
authors.forename: C
authors.initials: C
authors.lastname: Meneghini
authors.forename: I
authors.initials: I
authors.lastname: Pis
authors.forename: S
authors.initials: S
authors.lastname: Nappini
authors.forename: S
authors.initials: S
authors.lastname: Mobilio
authors.forename: M V
authors.initials: MV
authors.lastname: Russo
authors.forename: G
authors.initials: G
authors.lastname: Polzonetti
mesh_terms: D053768:Metal Nanoparticles / Q000737:chemistry*; D015394:Molecular Structure; D009944:Organoplatinum Compounds / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory; D012834:Silver / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D017356:Synchrotrons; D056928:X-Ray Absorption Spectroscopy
chemical_list: D009944:Organoplatinum Compounds; D013438:Sulfhydryl Compounds; D012834:Silver