Gold Nanoparticles Stabilized by Single Tripodal Ligands

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.