Binding Affinity of Monoalkyl Phosphinic Acid Ligands toward Nanocrystal Surfaces

We recently introduced monoalkyl phosphinic acids as a ligand class for nanocrystal (NC) synthesis. Their metal salts have interesting reactivity differences compared to carboxylates and phosphonates provide cleaner work-up phosphonates. However, little is known about the surface chemistry of NCs with phosphinate ligands. Here, we probe relative binding affinity ligands respect other X-type perform competitive exchange reactions carboxylate phosphonate at hafnia, cadmium selenide, zinc sulfide NCs. monitor shell composition by solution 1H 31P NMR spectroscopy. Using acid an ether functionality, gain additional signature, apart from typical alkene resonance in oleic oleylphosphonic acid. find that are easily exchanged upon exposure acids, whereas equilibrium reached between phosphinates phosphonates, slightly favor (K = 2). Phosphinic thus intermediate carboxylic phosphonic all studied. These results enable sophisticated use NC synthesis post-synthetic engineering.