Cu(II), Ni(II) and Fe(II) complexes with a new substituted [1,2,4] triazole Schiff base derived from 4-amino-5-(thien-2-yl ethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one and 2-hydroxy-1-naphthaldehyde: synthesis,characterization and a comparison of theoretical and experimental results by Ab inito calculation

The synthesis and structural properties of two novel compounds, 4-amino-5-(thien-2-yl ethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one and 4-{[(2-hydroxy-1-naphthyl)methyl-ene]amino}-5-(thien-2-ylmethyl) − 2,4-dihydro-3H-1,2,4-triazol-3-one have been described. 4-Amino-5-(thien-2-ylmethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one was synthesized by treating N-propionyl-2-thien-2-ylethane-hydrazonoate with hydrazine hydrate and the Schiff base was obtained from condensation of substituted amine with 2-hydroxy-1-naphthaldehyde. The Cu(II), Ni(II) and Fe(II) complexes were prepared and characterized by elemental analyses, IR, magnetic moment, UV–Vis, mass spectral data and ¹H- and ¹³C-NMR IR spectra. The Schiff base is coordinated to the metal ions in a tridentate manner with OON donors of the phenolic O, carbonyl O and triazolic N. From the magnetic and UV spectral data, it was found the geometrical structure of Cu(II) and Fe(II) ions are octahedral while Ni(II) ion is square planar.Ab-inito 6-31 G* level calculations provided structural information and IR data that were in good agreement with experimental results.