Metal(II) Formates (M = Fe, Co, Ni, and Cu) Stabilized by Tetramethylethylenediamine (tmeda): Convenient Molecular Precursors for the Synthesis of Supported Nanoparticles

γ ‐Alumina supported 3d transition‐metal nanoparticles are commonly used catalysts for several industrial reactions, such as Fischer‐Tropsch , reforming, methanation, and hydrogenation reactions. However, the activity of such catalyst is often limited by the low metal dispersion and a high content of irreducible metal, inherent to the conventional preparation methods in aqueous phase. In this context, we have recently shown that [{Ni( μ 2 ‐OCHO)(OCHO)(tmeda)} 2 ( μ 2 ‐OH 2 )] (tmeda=tetramethylethylenediamine) is a suitable molecular precursor for the formation of 1–2 nm large nanoparticles onto alumina. Here, we explore the synthesis of the corresponding Fe, Co, and Cu molecular precursors, namely [{Fe( μ 2 ‐OCHO)(OCHO)(tmeda)} 4 ], [{Co( μ 2 ‐OCHO)(OCHO)(tmeda)} 2 ( μ 2 ‐OH 2 )], [Cu( κ 2 ‐OCHO) 2 (tmeda)], which are, like the Ni precursor, soluble in a range of solvents, rendering them convenient metal precursors for the preparation of supported metallic nanoparticles on γ ‐alumina. Using a specific adsorption of the molecular precursor on γ ‐alumina in a suitable organic solvent, treatment under H 2 provides small and narrowly distributed Fe (2.5±0.9 nm), Co (3.0±1.2 nm), Ni (1.7±0.5 nm), and Cu (2.1±1.5 nm) nanoparticles. XAS shows that the proportion of MAl 2 O 4 (M = Co, Ni, Cu) is small, thus illustrating the advantage of using these tailor‐made molecular precursors.