Synthesis, Structural Elucidation, and Biological Evaluation of 3d Transition Metal Complexes with a Novel Schiff Base Ligand: 2-(Thiophene-2-formyl imino) Sulphanilamido Thiazole
Keywords:
Spectroscopic data confirmed the structure of the Schiff base ligand and revealed its coordination to metal ions as a tridentate ligand through an O, N, S donor set. Electronic spectral and magnetic moment data suggested octahedral geometries for the Mn(II), Co(II), and Ni(II) complexes, a square planar geometry for the Cu(II) complex, and a tetrahedral geometry for the Zn(II) complex. In vitro antimicrobial assays demonstrated that the metal complexes exhibited promising and enhanced activity compared to the free ligand against tested bacterial and fungal strains.Abstract
Schiff base ligands are pivotal in medicinal inorganic chemistry, particularly when incorporating biologically active pharmacophores such as thiazole and sulfonamide moieties, which can significantly enhance the therapeutic potential of their metal complexes. Objective: This study aimed to synthesize a novel Schiff base ligand (H₂L) via the condensation of sulfathiazole and thiophene-2-carbaldehyde, and to subsequently prepare and characterize its coordination complexes with 3d transition metal ions, including Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). Methods: The ligand was synthesized under reflux conditions. The metal complexes were prepared by reacting metal chlorides or acetates with the synthesized ligand in a methanolic medium. The structures of the ligand and its complexes were elucidated using elemental analysis (CHN), molar conductivity, Fourier-Transform Infrared (FT-IR) spectroscopy, UV-Vis-NIR spectroscopy, Nuclear Magnetic Resonance (¹H & ¹³C) spectroscopy (for the ligand), Electron Spin Resonance (ESR) spectroscopy (for the Cu(II) complex), magnetic susceptibility measurements, thermogravimetric analysis (TGA), and Powder X-ray Diffraction (PXRD).
