Mechanistic Study of Continuous Reactive Aromatic Organothiol Adsorption onto Silver Nanoparticles

Abstract

Organothiol (R-SH) (OT) adsorption onto silver nanoparticles (AgNPs) in water was studied for a series of aromatic OTs including p-methylbenzenethiol (p-MBT), p-benzenedithiol (p-BDT), and 2-mercaptobenzimidazole (2-MBI). Unlike the common view that OT forms monolayer adsorption on AgNPs, we found that these aromatic OTs continuously reacted with AgNPs through formation of RS–Ag complexes until complete OT or AgNP consumption occurred. The RS–Ag complex can remain on the AgNP surface, converting the AgNPs into core–shell structures. The OT adsorption onto AgNPs occurs predominately through reaction with silver oxide present on the AgNP surfaces before the OT addition or formed from environmental oxygen in the presence of OT. The RS–H protons are completely released when both p-MBT and 2-MBI reacted with AgNP, Ag2O, and AgNO3. However, a substantial fraction of S–H bonds remained intact when p-BDT, the only dithiol used in this work, is adsorbed on AgNPs or reacted independently with Ag2O and AgNO3. The new insights from this work should be important for understanding OT interaction with AgNPs in water and the SERS spectra of the OT adsorbed onto AgNPs.

Structures and Conformations of Alkanedithiols on Gold and Silver Nanoparticles in Water

“…33 The fact that AgNP are substantially disintegrated in AgNP/ADT mixtures, but not in their corresponding AgNP/AMT solutions indicates that ADT is not as effective as AMT in passivating the AgNP from oxidative disintegration. This observation is consistent with the fact that ADT is drastically more disordered than AMT on AgNP surfaces.…”

“…27,[33][34][35][36] The goal of this current study is to determine the structure and compositions of the alkanedithiol (ADT, HS-(CH 2 ) n -SH) adsorbed onto AuNPs and AgNPs in water, using a combination of SERS, inductively-coupled were purchased within the past four months and they are used as received. The reagent purity are all 95% or above.…”

Label-free detection of lysozyme in wines using an aptamer based biosensor and SPR detection

“…The SPR gold interfaces were cleaned using a NaBH4 treatment [20]. After rinsing several times with water and ethanol and drying under a gentle stream of nitrogen, the interfaces were immersed in a 50 M "PEG-COOH" ethanolic solution for three days.…”

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

“…8 Organothiols and thiol-containing biomolecules have been utilized in a wide range of AgNP synthesis and applications. [9][10][11][12] They are the most popular capping agents in AgNC synthesis, 4,11,[13][14][15] and the commonly used model molecules in studying AgNP SERS activities. [16][17][18][19] However, current understanding of organothiol interactions with AgNPs and silver ions remains incomplete.…”

“…For example, aromatic organothiols induce rapid AgNP disintegration, but AgNPs mixed with long-chain alkylthiols are relatively stable in water. 10,19 The latter is because long alkylthiols are highly ordered on the AgNPs, 19 imposing significant steric hindrance for the silver oxidation reaction. 4 In theory, organothiols can also stabilize AuNPs.…”