New acyclic 1,2,4-triazole-based Schiff base hydrazone: Synthesis, characterization, spectrophotometric and computational studies

A new 1,2,4-triazole-based Schiff base hydrazone with N, O, S donor set of atoms, H4L, has been prepared by condensation reaction of N,N′-bis(3-formyl-5-methylsalicylidene)ethane-1,2-diamine, H2L, with 4-amino-3-(4-pyridyl)-5-mercapto-1,2,4-triazole. The structure of H4L was characterized by using FT-IR, UV–Vis and 1H NMR spectroscopic methods as well as elemental analysis data. The formation constants of copper(II), cadmium(II), mercury(II) and silver(I) complexes of H4L in DMSO were calculated using a hard model chemometrics method applying the spectrophotometric data. The protonation constants of H4L were also measured in DMSO-water (1:10) mixture. Furthermore, 1H chemical shifts of H4L were studied by the gauge independent atomic orbital (GIAO) and continuous set of gauge transformations (CSGTs) methods at the level of density functional theory using B3LYP/6-311++G* basis sets in gas phase. The computed chemical shifts are in reasonably good agreement with the experimental data.

Graphical abstractNew acyclic 1,2,4-triazole-based Schiff base hydrazone; synthesis, characterization, spectrophotometric and computational studies.Formation constants of copper(II), cadmium(II), mercury(II) and silver(I) complexes of new bisiminated 1,2,4-triazole-based Schiff base hydrazone in DMSO have been determined by hard model chemometrics method. Furthermore, 1H chemical shifts of the prepared ligand were studied by the GIAO/DFT and CSGT/DFT methods using B3LYP/6-311++G* basis sets.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of new acyclic 1,2,4-triazole-based Schiff base hydrazone is reported. ► Formation constants of metal complexes were determine by hard model chemometrics method. ► The 1H chemical shielding of ligand was studied by GIAO and CSGT methods at DFT level of theory.