Acetone solvated Au nanoparticles (Au NPs) were prepared by Metal Vapour Synthesis (MVS) co-condensing Au and acetone vapours. Nanoparticles growth was quenched at different times by using decylamine (DA) as stabilizer and DA-stabilized Au NPs were characterized by UV-Vis, NMR DOSY and HRTEM techniques. The dependence of metal clustering processes on gold concentration was investigated.