The widely used preparation of Ni(0) nanoparticles from [Ni(acac)(2)] (acac=acetylacetonate) and oleylamine, often considered to be a thermolysis or a radical reaction, was analyzed anew by using a combination of DFT modeling and designed mechanistic experiments. Firstly, the reaction was followed up by using TGA to evaluate the energy barrier of the limiting step. Secondly, all the byproducts were identified using NMR spectroscopy, mass spectrometry, FTIR, and X-ray crystallography. These methods allowed us to depict both main and side-reaction pathways. Lastly, DFT modeling was utilized to assess the validity of this new scheme by identifying the limiting steps and evaluating the corresponding energy barriers. The oleylamine was shown to reduce the [Ni(acac)(2)] complex not through a one-electron radical mechanism, as often stated, but as an hydride donor through a two-electron chemical reduction route. This finding has strong consequences not only for the design of further nanoparticles syntheses that use long-chain amine as a reactant, but also for advanced understanding of catalytic reactions for which these nanoparticles can be employed.

The reactions of the samarium(II) complexes Tmp 2 Sm (Tmp = 2,3,4,5-tetramethyl-1H-phosphol-1-yl) and Cp* 2 Sm(THF) 2 (Cp* = 1,2,3,4,5-tetramethyl-2,4-cyclopentadien-1-yl) with pyridine were found to be different, despite the fact that the Cp* and Tmp π-ligands are similar in size. With Tmp 2 Sm, a simple adduct, Tmp 2 Sm(pyridine) 2 is isolated, while with Cp* 2 Sm(THF) 2 pyridine is dimerized with concomitant oxidation of samarium to form [Cp* 2 Sm-(C 5 H 5 N)] 2 [μ-(NC 5 H 5 −C 5 H 5 N)]. However, reaction of Tmp 2 Sm with acridine, a better π-acceptor than pyridine, did result in acridine dimerization and the isolation of [Tmp 2 Sm] 2 [μ-(NC 13 H 9 −C 13 H 9 N)]. DFT calculations on the model structures of Tmp 2 Sm and Cp* 2 Sm, and on the single electron transfer step from Sm to pyridine and acridine in these ligand environments, confirmed that, even though the Sm−πligand bonds are mostly ionic, the different electronic properties of the Tmp ligand versus that of Cp are responsible for the difference in reactivity of Tmp 2 Sm and Cp* 2 Sm.■ EXPERIMENTAL SECTION Computational Details. Calculations were performed with the GAUSSIAN 03 suite of programs. 10 DFT was applied by means of the