Binuclear organometallic Pt(II) complexes as stabilizing ligands for gold and silver metal nanoparticles

The bifunctional hybrid thioester ligands containing square planar Pt(II) centers 2,7-bis[2-(trans-acetylthio-bis-(tributylphosphine)platinum)ethynyl]-9,9-didodecyl-9H-fluorene (1) and trans-4,4?-bis[2-(trans-acetylthio-bis-(tributylphosphine)platinum)ethynyl]stilbene (2) have been prepared in a four-step procedure and used as stabilizing and interconnecting ligands for gold and silver nanoparticles (MNPs), formed in-situ upon deacylation of the MeCOS-Pt(II)-terminal groups. The metallic surface is linked to the Pt(II) centers of the ligands via M-S-Pt(II) bridges. The size of the AuNPs and AgNPs which aggregate into a bi-dimensional network through hybrid metal-organic bridges was controlled by careful choice of synthetic parameters. The morpho-structural features of the nanoparticles, investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and synchrotron radiation induced X-ray photoelectron spectroscopy (SR-XPS), highlighted the linkage between the nanoparticles, featuring diameters below 10 nm.