Proton Initiated Ligand Exchange Reactions for Colloidal Nanocrystals Functionalized by Inorganic Ligands with Extremely Weak Coordination Ability

Replacing initial long chain organic ligands by small, stable, and conductive inorganic ligands (ILs) via inorganic ligand exchange reaction (ILER) opens up new opportunities for the functionalization and application of colloidal nanocrystals (NCs). Although IL functionalized NCs have been successfully obtained via ILER for most ILs, some common anions, including F-, NO3-, SO42-, and ClO4- with extremely weak coordination ability, are hardly explored. Herein, we demonstrate for the first time the access of these IL capped NCs via ILER by using H+ as the electrophile reagent, which efficiently and irreversibly strips off the original organic ligands first. A long-term colloidal stability can be realized for these anion capped NCs via the replacement of H+ by other suitable monovalent counterions. It is believed that the successful capping with these hard ILs for soft NCs such as CdSe will not only promote the development of IL exchange theory and mechanism but also significantly enrich the toolbox of colloidal NCs and provide great opportunities in the design and construction of new NC-based devices.