Dithiosulfindene Adsorption and Reaction on Gold Nanoparticles in Water

Abstract

Dithiosulfindene (DTS) is a model molecule for dithiolethiones, a class of biomedically important sulfur-rich compounds with a general formula R1-S-S-C(=S)-R2. Reported herein is a combined experimental and computational study of DTS interactions with plasmonic gold nanoparticles (AuNPs) in water. DTS adsorptions and reactions on AuNPs were investigated using a combination of UV-vis, Raman, and surface enhanced Raman spectroscopic (SERS) methods. The saturation packing density of DTS on AuNPs is 596 pmol/cm2, and its structure and conformation on AuNP surfaces depends critically on its packing density. NaOH reacts with DTS both in water and on AuNPs, converting DTS into thiosalicyclic acid (TSA). TSA produced by NaOH reaction with DTS preadsorbed onto AuNPs partitions between remaining on AuNP surfaces and being released to the supernatant of the reaction solution. UV-vis measurements revealed that NaOH reaction with DTS in solution and on AuNPs both follow first order kinetics with a rate constant of 0.7...