Bidentate Acyclic Diamino Carbene-Stabilized Gold Nanoparticles from Symmetric and Asymmetric Gold(I) Complexes: Synthesis, Characterization, and Catalytic Activity

A series of gold nanoparticles (AuNPs) stabilized by bidentate acyclic diamino carbenes (ADCs) were synthesized via the reduction of dimeric gold(I) complexes. The resulting ADC-AuNPs were characterized by NMR spectroscopy, UV-Vis spectroscopy, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA), revealing monodisperse particles with sizes ranging from 1.7 to 3.3 nm. This synthetic approach was extended to an asymmetric dinuclear ADC-gold(I) complex, affording slightly larger AuNPs (~4 nm) upon reduction. The ADC-AuNPs with shorter linkers exhibited significant catalytic activity for the reduction of 4-nitrophenol, demonstrating a versatile and efficient route to catalytically active gold nanoparticles stabilized by both symmetric and asymmetric ADC ligands.