Deciphering Ligands’ Interaction with Cu and Cu₂O Nanocrystal Surfaces by NMR Solution Tools

Abstract

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.

Synthesis of Metal Nanoparticles and Metal Fluoride Nanoparticles from Metal Amidinate Precursors in 1-Butyl-3-Methylimidazolium Ionic Liquids and Propylene Carbonate

“…Soft wet‐chemical synthesis in organic solvents from metal–organic complexes is an important method to obtain metal or metal alloy nanoparticles . Metal amidinates are important precursors for metal nanoparticles for thin metal films from low‐pressure chemical vapor deposition (CVD) and atomic layer deposition (ALD) …”

“…Soft wet-chemical synthesis in organic solvents from metal-organic complexes is an important methodt oo btain metal or metal alloy nanoparticles. [1][2][3][4] Metal amidinates are important precursors for metal nanoparticles [5,6] for thin metal films from low-pressure chemical vapor deposition( CVD) and atomic layer deposition (ALD). [7,8] Herein, we report the use of metal amidinates [M{MeC-(NiPr) 2 } n ]o fm anganese,i ron, cobalt, nickel, and coppera sp recursors for the synthesis of nanomaterials in ionic liquids (ILs) or in propylene carbonate (PC) to yield selectively transitionmetal nanoparticles (M 0 -NPs) or metal fluoride nanoparticles (MF 2 -NPs) as stable colloids (Scheme1).…”

Controlled metal nanostructures: Fertile ground for coordination chemists

“…Au [119], Ru [38], Re [47] Pd [120], Pt [121],Co [22], Ag [78] or Cu [114] NPs. Similarly, isonitriles are used on Pd [122], [123], Ag or Au NPs [124], [125], [126], nitriles on Pt-Fe alloy NPs [127].…”

“…Phosphines are used on e.g. Pd [101], [102], [103], Pt [104], [41], or Ru [105] NPs, diphosphites on Pd [106], [107], [108], as well as on Ru, Rh, or Ir [109] NPs or phosphine oxide on Co [110], indium [111] or Au ones [112], phosphinine ligands on Au NPs [113], and phosphonic acid on Cu NPs [114]. Care should be taken when phosphines or phosphine oxides are envisaged for the stabilization of MNPs.…”

Soft, Wet‐Chemical Synthesis of Metastable Superparamagnetic Hexagonal Close‐Packed Nickel Nanoparticles in Different Ionic Liquids

“…Soft, wet‐chemical synthesis in organic solvents from metal–organic complexes is an important route to nanometals and allows the preparation of metals and alloys in the nanometer scale regime . Metal amidinates (Scheme ) have been investigated and widely used as precursors for metal nanoparticles and thin metal films in low‐pressure chemical vapor deposition (CVD) or atomic layer deposition (ALD) …”