Synthesis and structural characterization of N-(2-{[(2E)-2-(2-hydroxybenzylidene)- hydrazinyl] carbonyl}-phenyl)benzamide (HL) and its Co(II), Fe(III), Cu(II) and Zn(II) complexes. X-ray crystal structure of HL

N-(2-{[(2E)-2-(2-hydroxybenzylidene)hydrazinyl]carbonyl}phenyl)benzamide (HL) and its Co(II), Fe(III), Cu(II) and Zn(II) perchlorate complexes were synthesized. The structures of HL and its complexes were confirmed on the basis of elemental analysis and FT-IR, FT-Raman, 1H-NMR spectra. TGA, magnetic moment and molar conductivity measurements were carried out for the complexes. In addition, the crystal structure of HL was determined by X-ray diffraction at room temperature. It crystallizes in the monoclinic, space group C2/c and Z=4. HL has an interesting structure due to the presence of two intramolecular hydrogen bonds. It behaves as a bidentate ligand through the C=N nitrogen and OH oxygen atoms in its chelate complexes that they have 1:2 M:L (metal:ligand) ratio. The Fe(III), Cu(II) and Zn(II) complexes, [Fe(HL)(L)(H2O)2](ClO4)2, [Cu(HL)2](ClO4)2∙3H2O, [Zn(HL)2](ClO4)2·H2O are 2:1 electrolytes whereas the Co(II) complex, [Co(HL)(L)(H2O)]ClO4·H2O, is 1:1 electrolyte according to the molar conductivity data.