Liquid–Liquid Interfacial Electron Transfer from Ferrocene to Gold(III): An Ultrasimple and Ultrafast Gold Nanoparticle Synthesis in Water under Ambient Conditions

Ferrocene (Fc) in ether reduces HAuCl₄ in water within seconds under ambient conditions in air upon stirring, forming ferricinium chloride stabilized water-soluble 20 nm gold nanoparticles (AuNPs) that are redispersible in the presence of poly­(<i>N</i>-vinylmethylpyrrolidone) or NaBH₄ + thiol. After reduction with NaBH₄ yielding Fc and 26 nm sodium poly­(hydroxyborate) stabilized AuNPs, the core size no longer changes following reactions with thiols providing (RS)_<i>n</i>AuNPs