Synthesis, X-ray structure, theoretical investigation, corrosion inhibition and antimicrobial activity of benzimidazole thioether and theirs metal complexes

Abstract Synthesis, characterization, corrosion inhibition as well as antimicrobial activity of the coordination compounds {Co(bbms)Cl 2 }, {Zn(bbms)Cl 2 }, {Co(btmb)Cl 2 } and {Zn(btmb)Cl 2 } containing benzimidazole thioether have been described. Co(bbms) and Zn(bbms) as well as Co(btmb) and Zn(btmb) are isostructural with space group Pbca and P21 respectively. The coordination polyhedron around the metal center for all complexes may be described as a quasi-regular tetragonal geometry. The corrosion inhibition study of these complexes for steel in 0.5 M H 2 SO 4 medium has been investigated using potentiodynamic polarization and EIS techniques. These later show the corrosion inhibition ability of the prepared complexes for steel in acid medium. A new procedure has been developed for antimicrobial assay using a solid tablet of the corresponding complexes. These later show moderate to significant antimicrobial activities against: Pseudomonas syringae , Staphylococcus aureus and Pichia caribbica . DFT/BP86 calculations have been carried out on the neutral complexes and on the monoanionic of ( 1 ) and ( 3 ) forms of singlet and triplet species. The optimized structures reproduce those observed experimentally, while the reduced ones undergo remarkable geometrical parameters variations.