4-Aminothiophenol Photodimerization Without Plasmons.

Abstract

The photodimerization of 4‐aminothiophenol (PATP) into 4,4′‐dimercaptobenzene (DMAB) has been extensively utilized as a paradigm reaction to probe the role of surface plasmons in nanoparticle‐mediated light‐driven processes. Here I report the first observation of the PATP‐to‐DMAB photoreaction in the absence of any plasmonic mediators. The reaction was observed to occur with different kinetics either for PATP adsorbed on non‐plasmonic nanoparticles (TiO2, ZnO, SiO2) or deposited as macroscopic droplets. Confocal microRaman spectroscopy enabled to investigate the reaction progress in different plasmon‐free contexts, either aerobic or anaerobic, suggesting a new interpretation of the photodimerization process, based on direct laser‐induced activation of singlet oxygen species. These results provide new insights in light‐driven redox processes, elucidating the role of sample morphology, light and oxygen.