title: Carboxylic-Acid-passivated metal oxide nanocrystals: ligand exchange characteristics of a new binding motif.
abstract: Ligand exchange is central in the processing of inorganic nanocrystals (NCs) and requires understanding of surface chemistry. Studying sterically stabilized HfO2 and ZrO2 NCs using (1) H solution NMR and IR spectroscopy as well as elemental analysis, this paper demonstrates the reversible exchange of initial oleic acid ligands for octylamine and self-adsorption of oleic acid at NC surfaces. Both processes are incompatible with an X-type binding motif of carboxylic acids as reported for sulfide and selenide NCs. We argue that this behavior stems from the dissociative adsorption of carboxylic acids at the oxide surface. Both proton and carboxylate moieties must be regarded as X-type ligands yielding a combined X2 binding motif that allows for self-adsorption and exchange for L-type ligands.
authors: Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium).
authors: Jonathan
authors: J
authors: De Roo
authors: Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium).
authors: Yolanda
authors: Y
authors: Justo
authors: Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium).
authors: Katrien
authors: K
authors: De Keukeleere
authors: Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281-S4, 9000 Gent (Belgium).
authors: Freya
authors: F
authors: Van den Broeck
authors: Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281-S4, 9000 Gent (Belgium).
authors: José C
authors: JC
authors: Martins
authors: Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium).
authors: Isabel
authors: I
authors: Van Driessche
authors: Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Gent (Belgium). zeger.hens@ugent.be.
authors: Zeger
authors: Z
authors: Hens
keywords: CdSe; NMR spectroscopy; ligand exchange; nanoparticles; surface chemistry