Conventional and Microwave-Assisted Synthesis, Antimicrobial and Antitumor Studies of Tridentate Schiff Base Derived from O-vanillin and Phenyl Urea and its Complexes

A tridentate Schiff base ligand (E)-1-(2-hydroxy-3-methoxybenzylidene)-3-phenylurea derived from o-vanillin and phenyl urea in 1:1 molar ratio. Also, the metal complexes of Mn (II), Co (II), Ni (II), Cu (II), Zn (II) and Zr (IV) were synthesized using the microwave-assisted irradiation and conventional methods. The ligand and its complexes 1-6 were characterized using the elemental analysis, FT-IR, UV-vis, 1HNMR, mass spectroscopy as well as thermo-gravimetric analysis (TGA). The geometry structures of the complexes were confirmed using electronic spectra, electron spin resonance (ESR) and magnetic moment. Study of the thermal dehydration and decomposition of the Co (II), Ni (II), and Zn (II) complexes kinetically using the integral method applying the Coats–Redfern and Horowitz Metzger equation. The ligand and its metal complexes were screened for the antimicrobial activity against the gram-positive, gram-negative bacteria and fungi also, the cytotoxic activity was evaluated against two cell lines; human colon carcinoma (HCT-116) and breast carcinoma cells (MCF-7).