New cobalt(II) Schiff base complex: synthesis, characterization, DFT calculation and antimicrobial activity

Abstract A new cobalt(II) Schiff-base complex [Co(L)2] was prepared by using equivalent molar of Schiff-base ligand [HL=(E)-N'-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide] and CoCl2•6H2O. The structure of the complex was characterized by single-crystal X-ray diffraction, IR, ESI-MS, elemental analysis and DFT method. X-ray crystal structure analysis showed that the complex crystallized in space group Pbca, with two symmetry-independent molecules. The experimental vibrational bands(IR) have been discussed and assigned based on DFT calculations. The antibacterial activity of Schiff base and its complex against S. pombe were assessed by bio-microcalorimetry at 32 oC. Some thermokinetic parameters (k, Pmax, tG and Qtotal) were derived from the metabolic power–time curves, and their quantitative relationship with the concentration were analyzed. The half inhibition concentration (IC50) of Schiff base and its complex were calculated to be 1.18×10-2 mol L-1 and 1.07×10-3 mol L-1, respectively. The inhibition effect of the complex showed much stronger than that of Schiff base.