α-Diimine transition-metal complexes: Mechanochemistry − A new synthetic approach

Preliminary results on the preparation of nickel(II) and cobalt(II) complexes containing α-diimine ligands using a mechanochemical approach are presented. The solvent-free reaction of [NiBr2(DME)] (DME = 1,2-dimethoxyethane) with the appropriate α-diimine ligand led to the formation of the expected Ni(II) complexes in very short reaction times and with quantitative yields. The same compounds were also successfully synthesised when NiBr2 was employed. This methodology was extended to the preparation of [Co(α-diimine)Cl2] complexes through the reaction of CoCl2 with different α-diimine ligands. These compounds were characterised by XRPD and SCXRD, when possible. The results obtained confirm that mechanochemistry has an enormous potential and that is an effective technique for the synthesis of coordination and organometallic compounds.