Deciphering ligands' interaction with Cu and Cu2O nanocrystal surfaces by NMR solution tools.
The hydrogenolysis of [Cu2{(iPrN)2(CCH3)}2] in the presence of hexadecylamine (HDA) or tetradecylphosphonic acid (TDPA) in toluene leads to 6-9 nm copper nanocrystals. Solution NMR spectroscopy has been used to describe the nanoparticle surface chemistry during the dynamic phenomenon of air oxidation. The ligands are organized as multilayered shells around the nanoparticles. The shell of ligands is controlled by both their intermolecular interactions and their bonding strength on the nanocrystals. Under ambient atmosphere, the oxidation rate of colloidal copper nanocrystals closely relies on the chemical nature of the employed ligands (base or acid). Primary amine molecules behave as soft ligands for Cu atoms, but are even more strongly coordinated on surface Cu(I) sites, thus allowing a very efficient corrosion protection of the copper core. On the contrary, the TDPA ligands lead to a rapid oxidation rate of Cu nanoparticles and eventually to the re-dissolution of Cu(II) species at the expense of the nanocrystals.
LCC-CNRS (Laboratoire de Chimie de Coordination), 205, route de Narbonne, BP44099, 31077 Toulouse (France).
Arnaud
A
Glaria
Jérémy
J
Cure
Kilian
K
Piettre
Yannick
Y
Coppel
Cédric-Olivier
CO
Turrin
Bruno
B
Chaudret
Pierre
P
Fau
D000588:Amines / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D053758:Nanoparticles / Q000737:chemistry; D010084:Oxidation-Reduction; D010757:Phosphorous Acids / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D020349:Surface Plasmon Resonance
D000588:Amines; D008024:Ligands; D010757:Phosphorous Acids; C570063:phosphonic acid; D003300:Copper; C030973:cupric oxide
NMR spectroscopy; copper; nanoparticles; oxidation; surface chemistry