Plasmon-Mediated Selective Chemical Reaction of Aromatic Molecules with Amino and Nitro Functional Groups

Abstract

The plasmon-mediated chemical reaction (PMCR) of aromatic molecules with different functional groups is the frontier topic in the photochemistry area. In this work, two typical Ag-plasmon-catalyzed reactions in aqueous environments are studied, in which the selective reduction reactions of 2-amino-5-nitrobenzenethiol (2A-5NBT) molecules to 3,3′-dimercapto-4,4′-diaminoazobenzene (M1) and the reduction of M1 to 2,5-aminobenzenethiol (M2) by NaBH4 are observed. The mechanism of these two reactions is discussed combined with the calculated Raman spectra. These results demonstrate that 2A-5NBT molecules are selectively catalyzed to M1 in aqueous environments and M1 can be reduced to form M2 in the presence of NaBH4 as a reducing agent. Furthermore, the kinetics of the reduction reaction are analyzed based on surface-enhanced Raman spectroscopy (SERS), which conforms to the first-order kinetic process. This work provides a new perspective on the modulation of selective surface-catalyzed coupling reactions on 2A-5NBT molecules and facilitates the broadening of the research field of in situ monitoring of PMCRs by SERS technology.