Synthesis of Alkanethiolate-Capped Metal Nanoparticles Using Alkyl Thiosulfate Ligand Precursors for Selective Catalytic Reactions

Stable and isolable alkanethiolate-stabilized Pt nanoparticles (PtNP) were synthesized using the two-phase thiosulfate method with sodium S-alkylthiosulfate as ligand precursor. The mechanistic formation of octanethiolate-capped PtNP (Pt-SC8) from both sodium S-octylthiosulfate and 1-octanethiol ligands was investigated by using 1H NMR and UV-vis spectroscopy, which revealed the formation of different Pt complexes as the reaction intermediates. The partially poisoned PtNP with thiolate monolayer ligands was further investigated for the hydrogenation of various alkynes to understand the organic ligands-induced geometric and electronic surface properties of colloidal Pt nanoparticle catalysts. In addition, alkanethiolate-capped Pd nanoparticles (PdNP) were prepared using reversed thiosulfate addition method with S-octylthiosulfate as ligand precursor. Various synthetic conditions were applied to the modified two-phase method in order to control the average core size and surface ligand density. The obtained nanoparticles were characterized by 1H NMR, UV-vis spectroscopy, infrared spectroscopy (IR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM)