Comparative Studies of New Complexes Synthesized by Chemical and Tribochemical Reactions Derived from Malonic Acid Dihydrazide (L; MAD) with Cu<sup>2+</sup> and Co<sup>2+</sup> Salts

The reaction of L (MAD) with Cu2+ and Co2+ chlorides affords new metal complexes. The isolated solid complexes were synthesized by two different techniques i.e., chemical and tribochemical methods. Four new complexes were synthesized by direct chemical reactions of MCl2 (M = Co2+ and Cu2+) with MAD in absolute EtOH. The isolated solid complexes were used as starting compounds to synthesize another four new complexes using tribochemical technique by grinding the previous complexes in the solid state with excess KI in agate mortar. The results of the isolated complexes indicate the substitution of the chloride by iodide ions during grinding and extraction of the complexes by a mixture of solvents (EtOH + MeOH). Also, the results suggest that no reduction of Cu2+ or oxidation of Co2+ complexes is observed. The IR spectra of the complexes suggest that L acts in a bidentate manner. Moreover, the results of electronic spectra and magnetic measurements for the chloride and iodide complexes suggest distorted-octahedral and/or tetrahedral for Cu2+ and high-spin octahedral and/or tetrahedral structures around the Co2+ ion, respectively.