Synthesis, spectral, thermal, solid-state DC electrical conductivity and biological studies of Co(II) complexes with Schiff bases derived from 3-substituted-4-amino-5-hydrazino-1,2,4-triazole and substituted salicylaldehydes

A series of Co(II) complexes have been synthesized with Schiff bases derived from 3-substituted-4-amino-5-hydrazino-1,2,4-triazole and substituted salicylaldehydes. These complexes are insoluble in water but more soluble in DMF and DMSO. The complexes have been characterized by elemental analyses, spectral (IR, UV–Vis, 1H-NMR, FAB-mass, fluorescence), magnetic, thermal, solid-state DC electrical conductivity and molar conductance data. The molar conductivity values indicate that they are non-electrolytes. The elemental analyses of the complexes suggest a stoichiometry of the type Co · L1–L16 · 2H2O. The complexes have been considered as semiconductors on the basis of the solid-state DC electrical conductivity data. Fluorescence spectra of one Schiff base and its complex were investigated in various solvents and some of the Schiff bases and their complexes were evaluated for their antimicrobial activities.