From molecular Au(I) complexes to subnanoclusters and nanoparticles: study of the influence of secondary interactions in (photo)catalytic systems

In recent years, hydrogen bonding interactions have garnered significant interest, driven both by the increased use of this metal as catalyst and by the importance of these interaction in enhancing stability. Various studies have evaluated the influence of secondary interactions in the design of new gold-based catalysts, focusing primarily on the development of catalytically active systems. In this context, the present work does not aim primarily at stabilizing gold-based catalysts, but rather at analyzing the influence of weak interactions throughout the entire catalytic profile, with particular attention to their role in stabilizing transition states. Additionally, this work will address the influence of these weak interactions on the in-situ generation of catalytically active species, such as gold subnanoclusters. Similarly, their role in the stabilization of larger gold nanoparticles will be analyzed through their deposition on carbon-based matrixes. Everything constitutes a relevant strategy for the design of more efficient and durable catalytic systems. First, the catalytic ability of the polymeric complex [Au(C-CPh)]n in the A3 coupling reaction for the obtention of propargylamines has been evaluated. The active species involved in the catalyzed coupling reaction were identified through an experimental mechanistic study. Furthermore, the importance of weak interactions, specifically gold hydrogen bonds Au···H-C, has been assessed throughout the entire catalytic energy profile. On other hand, the ability of different functional groups to stabilize gold subnanoclusters (AuSNC), characterized by their short-lived nature and strong tendency to aggregate, has been evaluated. The presence of weak interactions, such as gold hydrogen bonds Au···H-C or multiple bonds interactions Au···π, can significantly contribute to the stabilization of these highly reactive species. The stabilizing ability, assessed through both experimental and computational methods, has enabled the extension of this study to catalytic applications. In this context, and considering the relevance of interactions between gold atoms and π electronic density of multiple bonds, the catalytic activity of gold subnanoclusters in the alkyne hydration has been evaluated. Moreover, the catalytic ability of gold nanoparticles stabilized on a polymeric matrix PEG-Au NPs has been studied. In this case, a photocatalytic study focused on the alkyne hydration reaction was carried out using these gold nanoparticles as the catalytic system. Thus, the synthetized material PEG-Au NPs has demonstrated excellent catalytic properties, with enhanced activity attributed to the continuous release of gold subnanoclusters into the reaction medium from larger gold nanoparticles stabilized within the polymeric matrix. The catalytic mechanism was determined to involve the generation of hot charge carriers due to the excitation of the 5d-6s6p interband region. Finally, a new in-situ synthetic method has been developed for the formation of gold nanoparticles stabilized on carbon-based matrixes, such as covalent organic frameworks (COFs). Thorough the in-situ reduction of organometallic gold(I) complexes, such as [Au(C6F5)(tht)], the growth and stabilization of nanoparticles approximately 2-4 nm in size within the cavities of the semiconductor (COF) material have been successfully achieved. Furthermore, the ability of these plasmonic materials to promote hydrogen generation by the dehydrogenation reaction of N-Heterocycles has been evaluated, achieving promising results under mild reaction conditions.

Grantor dc:publisher

Universidad de La Rioja (España)

Year dc:date

2025

Author dc:creator

• Sorroche Ezquerro, Alba

Contributors dc:contributor

• López de Luzuriaga Fernández, José María (Universidad de La Rioja)
• Monge Oroz, Miguel (Universidad de La Rioja)

Statement dc:rights

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Language dc:language

eng

Repository record dc:identifier

https://dialnet.unirioja.es/servlet/oaites?codigo=395308

OAI identifier oai:identifier

oai:dialnet.unirioja.es:TES0000023207