Contradictory Dual Effects: Organothiols Can Induce Both Silver Nanoparticle Disintegration and Formation under Ambient Conditions

Using propanethiol (PrT), 2-mercaptoethanol (ME), glutathione (GSH), and cysteine (Cys) as model thiols, we demonstrated herein that organothiols can induce both silver nanoparticle (AgNP) disintegration and formation under ambient conditions by simply mixing organothiols with AgNPs and AgNO 3, respectively. Mechanistically, organothiols induce AgNP disintegration by chelating silver ions produced by ambient oxygen oxidizing the AgNPs, while AgNP formation in AgNO 3 /organothiol mixtures is the result of organothiols serving as the reducing agent. Furthermore, surface-plasmon- and fluorescent-active AgNPs can be interconverted by adding excess Ag + or ME into the AgNP-containing solutions. Organothiols can also reduce gold ion in HAuCl 4 /organothiol solutions into fluorescence- and surface-plasmon-active gold nanoparticles (AuNPs), but no AuNP disintegration occurs in the AuNP/organothiol solutions. This work highlights the extraordinary complexity of organothiol interactions with gold and silver nanoparticles. The insights from this work will be important for AgNP and AuNP synthesis and applications.