Synthesis and characterization of 1,2,4-triazole containing Schiff base ligands and their CuII complexes

Department of Chemistry, Birla Institute of Technology, Mesra, Ranchi-835 215, Jharkhand, India

E-mail : subnaskar@yahoo.co.in Fax : 91-651-2275401

Manuscript received online 24 March 2016, accepted 17 October 2016

The condensation of 4-amino-1,2,4-triazole with 4-(diethylamino)salicylaldeyde, 5-Br-salicylaldeyde and 2- hydroxy-4-methoxybenzaldehyde in methanol to produce 1,2,4-triazole containing Schiff base ligands 2-((4H-1,2,4-triazole4-ylimino)methyl)-5-(diethylamino)phenol (L¹H), 2-((4H-1,2,4-triazole-4-ylimino)methyl)-4-bromophenol (L²H) and 2-((4H-1,2,4-triazole-4-ylimino)methyl)-5-methoxyphenol (L³H) respectively. The ligands on reaction with Cu(ClO₄ )₂ .6H2O in 2 : 1 molar ratio form Cu^II complexes (1-3) of general formula CuL₂ . The ligands and the complexes were characte-rized by means elemental analysis, FTIR, NMR, Mass, UV-Visible spectroscopy, luminescence spectroscopy. Electrochemical study on the ligands exhibit one oxidation peak due to phenol to phenoxyl radical and one or two reduction wave/s, while the Cu complexes show Cu^II/III oxidation and one ligand based reduction. Cu^I/II oxidation is masked inside the ligand based reduction processes.