Synthesis and Characterization of New Co(II), Ni(II), Cu(II) and Zn(II) with Bis-hydrazones Complexes

A number of new Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2,5-hexanedione bis(4-methylbenzoyl hydrazone)(HDMBH), 2,5-hexanedione bis(2-theonyl hydrazone)(HDTH) and 2,5-hexanedione bis(2-furoyl hydrazone)(HDFH) have been reported.The bis-hydrazone ligands were synthesized by the condensation of 2,5-hexanedione with (4-methylbenzoic acid hydrazide,2-thiophene carbohydrazide or 2-furic acid carbohydrazide) in 1:2 molar ratio. The reaction of metal(II) chlorides with the ligands in (1:1) molar ratio in ethanol in presence of triethylamine lead to the isolation of complexes having the general formula [M(L-2H)(H2O)2] where (M= Co(II), Ni(II), Cu(II) and Zn(II)) and (L-2H=doubly deprotonated ligand). The ligands and complexes have been characterized by elemental analysis, spectral (IR,UV-Vis), magnatic and molar conductance measurements, which revealed that the ligands HDMBH, HDTH, and HDFH act as dinegtive charge tetradentate (NNOO-2) donor ligands in the metal complexes, coordinated through the two azomethine group nitrogen atoms and the two enolic oxygen atoms. All complexes provide an octaheadral geomatry..