Sulfite-triggered surface plasmon-catalyzed reduction of p-nitrothiophenol to p,p′-dimercaptoazobenzene

The conversion of p -aminothiophenol (PATP) or p -nitrothiophenol (PNTP) to p,p ′-dimercaptoazobenzene (DMAB) has been used as model reactions to study plasmon-catalyzed reaction on nanoparticles. Herein, we report the conversion of PNTP to DMAB which is triggered by SO 3 2− ions on gold nanoparticles (AuNPs) for the first time. With the addition of SO 3 2− , the Raman peaks at 1139, 1392, 1437 cm −1 appears, which indicates the formation of DMAB. The experiment results suggested that the synergistic effect of AuNPs and SO 3 2− promoted the conversion of PNTP to DMAB. Besides, the proposed catalysis system is high selectivity to SO 3 2− ions, which provides a new detection route to SO 3 2− ions in the future. More importantly, the possible reaction mechanism has been put forward which is helpful to understand the surface plasmon-assisted catalytic reduction of PNTP on the surface of SERS substrate.