Mechanochemical syntheses of complexes through solid–solid reactions of divalent transition metal salts (Ni(II) or Cu(II)) with dimethylglyoxime

Solvent-free solid–solid reactions of dimethylglyoxime (H2dmg) with nickel(II) salts or copper(II) acetate were conducted mechanochemically. Three types of complexes, [Ni(Hdmg)2], [Ni(H2dmg)2]X2(X=Cl and NO3), and CuCH3COO(Hdmg), were identified by powder X-ray diffractometry (XRD) and elemental analysis. [Ni(Hdmg)2] was obtained for nickel salts of a weak acid and [Ni(H2dmg)2]X2 for those of a strong acid. The progress of some of the solid–solid reactions was followed by the measurement of weight change of the reaction mixture, suggesting that mechanical energy was utilized as a driving force for the reactions.