Gold Nanoparticles Stabilized by Single Tripodal Ligands

Abstract In order to coat the entire surface of gold nanoparticles (AuNPs) by a single ligand, tripodal macromolecules comprising benzylic thioethers coordinating to the AuNP surface are synthesized and their abilities to stabilize AuNPs are investigated. Out of the five studied ligands 1-5 , the tetraphenylmethane-based oligomers 4 and 5 display excellent AuNP coating features. Both ligand structures are able to control the dimensions of the AuNPs by stabilizing particles of narrow size distributions during their syntheses (1.05 ± 0.28 nm for Au-4 , and 1.15 ± 0.34 nm for Au-5 ). Closer inspection of these AuNPs by transmission electron microscopy and thermogravimetric analyses suggests that single ligands 4 and 5 are able to stabilize entire AuNPs. These particles Au-4 and Au-5 are obtained in good yields and display promising thermal stabilities (110 °C for Au-4 , and 95 °C for Au-5 ), making them interesting nanoscale inorganic-organic building blocks for further functionalization/processing by wet chemistry.