Novel NNO pincer type Schiff base ligand and its complexes of Fe(IIl), Co(II) and Ni(II): Synthesis, spectroscopic characterization, DFT, antibacterial and anticorrosion study

•Novel NNO pincer type Schiff base ligand was synthesized.•Six novel complexes of iron, cobalt and nickel with this ligand were synthesized.•Compounds were characterized by analytical, spectroscopic technique and geometry was optimized by DFT.•The FT-IR and electronic spectroscopy suggests that the ligand act as tridentate NNO donor and the complexes are octahedral.•Antibacterial and anticorrosion activities were performed. A novel NNO pincer type ligand (E)-N'-(phenyl(pyridin-2-yl)methylene)isonicotinohydrazide, PPMINH, was synthesized by condensation of 2-benzoyl pyridine and isonicotinylhydrazide. The ligand PPMINH on reaction with metal ions Fe(III), Co(II) and Ni(II) yielded six metal derivatives. Different analysis tools like; Elemental analyses, ESI-MS, FT-IR, molar conductivity, UV-spectra, magnetic susceptibility, NMR and EPR measurement were used. Theoretical FT-IR, 1H NMR and 13C NMR of ligand and complex 6 exhibits quite a good correlation coefficient. EPR spectrum of complex 6 at LNT suggests octahedral geometry around Ni(II). The ligand and complexes were screened for antibacterial activity. DFT has been carried out to optimize the geometry of the ligand and complexes. The properties most relevant to their potential action as corrosion inhibitors has been calculated all parameters of DFT from the inhibitor molecule to the metal atom. The corrosion inhibition effect of compounds on mild steel in an acidic medium was studied for 24, 48, 72 h using weight loss measurement. [Display omitted]