Unraveling the transformative pathways of Au-NHC and Au-alkynyl complexes and bridging the gap between molecular and nanoscale gold systems

Abstract

The aim of the present study was to explore the transformations of heteroleptic and homoleptic Au(I) complexes in detail and to systematically map their chemical evolutionary pathways. The relationships between these Au(I) complexes and the formation of gold nanoparticles and between the leaching processes of Au species from nanoparticles by NHC carbenes were studied. Moreover, Au-based reaction systems exhibit a wide variety of gold complexes and metallic gold particles depending on the conditions. The evolutionary pathways and transformations of homoleptic and heteroleptic Au(I) complexes were mapped using NMR, ESI-HRMS and electron microscopy. Depending on the conditions, a diverse range of metallic gold nanoparticles was formed. Interestingly, the formation of an NHC-Au(I) complex during the leaching of Au species from metallic nanoparticles in the presence of NHC carbenes was also noted. Our findings illustrate that the composition of Au-based reaction systems can simultaneously include various gold complexes and gold particles, reinforcing the potential of gold complexes to activate and transform molecules in a variety of reactions. By studying and understanding the physical and chemical properties of NHC-Au(I) complexes and the transformations they undergo under various conditions, we provide new opportunities for future research using gold-based systems for the development of dynamic catalytic systems.