Synthesis and Characterization of Gold Nanoparticles with Surface Ligands Derived from a Primary Phosphine

Reduction of HAuCl 4 · 3H 2 O with NaBH 4 in THF/H 2 O in the presence of the primary phosphine PH 2 Mes* (Mes* = 2,4,6-( t -Bu) 3 C 6 H 2 ) gave a mixture of ca. 1.3 nm diameter gold nanoparticles ( 1 ) and the known oligomers [Au(PHMes*)] n ( 2 ). Nanoclusters 1 might contain phosphido (PHMes*) or phosphinidene (PMes*) surface ligands, or both; they were characterized by elemental analysis, TGA, XPS, TEM, NMR, IR, and UV–Vis spectroscopies, and by their reactions with dodecanethiol, which gave PH 2 Mes*. Solid-state 31 P-NMR cross-polarization studies of 1 and 1D (prepared using NaBD 4 and PD 2 Mes* in THF/D 2 O) were consistent with the presence of phosphinidene surface groups.