Synthesis and characterization of some bi, tri and tetravalent transition metal complexes of N'-(furan-2-yl-methylene)-2-(p-tolylamino)acetohydrazide HL1 and N'-(thiophen-2-yl-methylene)-2-(p-tolylamino)acetohydrazide HL2.

The tetradentate Schiff bases hydrazone ligands HL(1), HL(2) and their metal complexes have been prepared and characterized by analytical, spectral (IR, UV-vis, (1)H NMR and ESR), molar conductivity, magnetic and TGA measurements. The results show that all the metal complexes are non-electrolytes, except (2, 10 and 20) which have ionic nature. The ligands coordinate in keto-neutral form and act as bidentate or tridentate for all metal complexes, except complexes (4 and 12). The ligands react as monobasic tetradentate and tridentate for complexes (4 and 12), respectively. Octahedral/tetrahedral Co(II) and Ni(II), octahedral/square planar Cu(II), and octahedral Mn(II), Fe(III), Cr(III), Ru(III), Hf(IV) and Zr(IV)O geometries were proposed. The ESR spectra of copper complexes (12 and 14) indicate d(x2-y2) ground state with covalent bond character. The thermal decomposition and the types of crystallized water for some metal complexes were studied. The studied metal complexes are very weakly active against the tested microorganisms.