Synthesis and characterization of Schiff base complexes containing sulfa groups

In this study, eight new Schiff base ligands 4-[(E)-(5-bromo-2-hydroxybenzylidene) amino]-N-(pyridin-2-yl)benzenesulfonamide (L1H), 4-[(E)-(2-hydroxy-5-nitro benzylidene)amino]-N-(pyridin-2-yl)benzenesulfonamide (L2H), 4-[(E)-(5-bromo-2-hydroxy-3-methoxybenzylidene)amino]-N-(pyridin-2-yl)benzenesulfonamide (L3H), 4-[(E)-(2-hydroxy-3-methoxy-5-nitrobenzylidene)amino]-N-(pyridin-2-yl)benzenesulfonamide (L4H), 4-{[(1E)-(5-bromo-2-hydroxyphenyl)methylene]amino}-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzene sulfonamide (L5H), 4-{[(1E)-(2-hydroxy-5-nitrophenyl)methylene]amino}-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzensulfonamide (L6H), 4-{[(1E)-(5-bromo-2-hydroxy-3-methoxyphenyl)methylene]amino}-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide (L7H), 4-{[(1E)-(2-hydroxy-3-methoxy-5-nitrophenyl)methylene]amino}-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide (L8H) were synthesized by the reactions of salicylaldehyde derivatives (5-Br; 5-NO2; 5-Br-3-OCH3; 5-NO2-3-OCH3) with sulfonamide derivatives (Sulfapyridine and Sulfamethizole). Using the ligands, 32 different complexes of Co(II), Ni(II), Cu(II) and Zn(II) in acetate forms were synthesized. The structures of ligands and complexes obtained were identified using Elemental Analysis, FT-IR, 1H-NMR, 13C-NMR, UV-Vis, Magnetic Susceptibility and Thermogravimetric Analysis as techniques. Co+2, Ni+2, Cu+2 and Zn+2 complexes have been found to have six coordinated octahedral geometry. All of the Schiff bases were found to be bidentate ligands involving the imino nitrogen and carboxyl oxygen atoms in the complexes. Metal to ligand ratio were found to be 1:1 for all of the complexes.