A Raman study on the intracluster interactions of aminothiophenol‐protected Ag7 clusters—Photo‐assisted N─N coupling reaction of the ligand

Abstract

AbstractWe have synthesized Ag7 nanoclusters via a facile one‐pot procedure with p‐aminothiophenol (PATP) as the ligand. The chemical component of this Ag7 cluster is determined to be Ag7(C6H6NS)7H+ by high‐resolution electrospray mass spectrometry, where a few fragment peaks are also observed such as [Ag7(C6H6NS)4H3Na]+. For this PATP‐protected Ag7 cluster, we have conducted a Raman investigation to probe in the intracluster interactions and find an essentially different Raman feature from that the nascent PATP ligand, pertaining to photo‐assistant catalytic conversion of PATP to p,p'‐dimercapto azobenzene (DMAB). Utilizing density‐functional‐theory (DFT) calculations, we have performed natural population analysis, natural bond orbital analysis, and electron density difference analysis to fully demonstrate the intracluster interactions between Ag7 clusters and the ligand. What is interesting is that the protection ligand PATP helps stabilize the Ag7 metallic core, and in turn, the metal core Ag7 catalyzes the protection ligands giving rise to N─N coupling reaction. On this basis, we have proposed a reaction pathway on a basis of DFT calculations to provide further insights into the reaction mechanism of PATP‐to‐DMAB conversion at the presence of the Ag7 clusters.