Metal(II) chloride complexes containing a tridentate N-donor Schiff base ligand: syntheses, structures and antimicrobial activity

One new tridentate N-coordinate ligand, N '-phenyl-N ''-(phenyl(pyridin-2-yl)methylene)ethane-1,2-diamine (L), has been synthesized and characterized. The tridentate N-3-coordinate ligand L has been used in the synthesis of a series of three mononuclear complexes [M(L)Cl-2] [M = Cu(II), Co(II), and Zn(II)] and one polynuclear Cd(II) complex [Cd(L)Cl-2](n) and these complexes were characterized by spectroscopic techniques. The structure of all the complexes has been solved by single-crystal X-ray diffraction studies and the data reveal that all mononuclear complexes have distorted square pyramidal geometry and the polynuclear Cd(II) complex has distorted octahedral geometry. The antimicrobial activity of all complexes was investigated against Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Proteus vulgaris) bacteria by disk diffusion method. The compounds demonstrated significant antimicrobial activity while [Cu(L)Cl-2] exhibited the best antibacterial activity among all the synthesized complexes.