C–C Coupling Reactions Catalyzed by Gold Nanoparticles: Evidence for Substrate-Mediated Leaching of Surface Atoms Using Localized Surface Plasmon Resonance Spectroscopy

Abstract

Heterogeneous metal nanocatalysts have recently emerged as attractive catalysts for a variety of couplings (e.g., C−C, C−N, C−S, C−O, etc.). However, the characterization of the catalytic pathway remains challenging. By exploiting localized surface plasmon resonance (LSPR) of the catalytically relevant gold (Au) nanostructure, we show that UV−vis spectroscopy can be used to confirm the homogeneous catalytic pathway. Specifically, we have demonstrated that Au nanoparticles under C−C coupling conditions undergo substrate-induced leaching to form homogeneous Au catalytic species. The LSPR spectroscopic approach opens a new door to track stability of nanocatalysts and characterize the catalytic pathway in a range of coupling reactions.

Stable and Surface‐active Co Nanoparticles Formed from Cation (x) Promoted Au/x‐Co3O4 (x=Cs) as Selective Catalyst for [2+2+1] Cyclization Reactions

“…These metal nanoparticles are gaining broad research interest in material science and chemistry because they display unusual chemical and physical properties, which are distinct from those of isolated molecule and bulk phase. [19,20] Notably, supported gold catalysts are known for their superior catalytic performance in several homogeneous and heterogeneous reactions, such as oxidation, [21] CÀ C coupling, [22] cycloaddition, [23] and reduction. [24] To afford a bimetallic structure, it essential to support gold nanoparticles on selected metal oxides, even though the support's choice affects the catalyst's performance and durability.…”

The Pivotal Role of Hot Carriers in Plasmonic Catalysis of C−N Bond Forming Reaction of Amines

“…Details of the experiments and synthesis are provided in Sections 1–3 of the Supporting Information. The heterogeneous catalytic pathway and the stability of the catalyst in presence of benzylamine and under photoirradiation were confirmed by monitoring the LSPR of the Au NPs through UV/Vis spectroscopy (see Section 15 of Supporting Information) [46, 47] . No leaching of Au atoms was observed.…”

The Role of Structural Flexibility in Plasmon-Driven Coupling Reactions: Kinetic Limitations in the Dimerization of Nitro-Benzenes

“…On the other hand, nanoscale heating can increase the speed of molecular reorganization and surface diffusion, thereby increasing the rate of favorable reactive encounters. Several important examples of plasmondriven bond formation were demonstrated in recent years 8,9 , including C-C bond formation in hydrocarbons 5,10 , Suzuki-Miyaura type reactions 11 and molecular dimerization reactions by N=N bond formation 5,12,13 .…”