Ferrocenyl Janus mixed-dendron stars and their stabilization of Au and Ag nanoparticles

Janus molecular architectures have recently attracted attention due to their structures and properties that differ from those of traditional symmetric structures. Herein, two new small redox-reversible mixed-dendron star-shape molecules containing three ferrocenyl groups have been synthesized by linking two distinct dendrons using an esterification reaction. These organometallic nano structures were characterized by ¹H and ¹³C NMR, MS, IR and UV–vis. spectroscopies and cyclic voltammetry confirming the number of ferrocenyl groups and AFM and DLS showing micellar assemblies. Au and Ag nanoparticles were stabilized in the presence of a mixed-dendron structure having amidoferrocene termini upon reaction of the nanoparticle metal precursor with NaBH₄. Compared reactions of the two star-molecules with HAuCl₄ showed a slow redox reaction leading to Au nanoparticles only with the star-molecule terminated with triazolyferrocene termini, which is taken into account by the difference of their redox potentials.