Novel Cr(III), Co(II), Zn(II) and Cd(II) Complexes of Schiff Base Ligand Derived from Salicyaldehyde and 3,4-Diaminotoluene: Synthesis, Characterization and Biological Screening

Abstract

A new Schiff base ligand (L) [2,2′-((1Z,1′Z)-((4-methyl-1,2- phenylene)bis(azanylidene))bis(methanylylidene))diphenol], derived from condensation of salicyaldehyde and 3,4-diamino toluene. The synthesized ligand was used for complexation with different metal ions Cr(III), Co(II), Zn(II) and Cd(II) using a molar ratio of metal:ligand (1:1). The synthesized ligand and its metal complexes were characterized by TLC, NMR (1H & 13C), UV-visible, mass, FT-IR spectroscopies, elemental analysis, magnetic moment and conductivity measurement. On the basis of above studies the proposed structure of synthesized mononuclear metal complexes have been found to possess tetrahedral geometry while Cr(III) and Co(II) ions possess octahedral geometry. The spectral studies revealed that the synthesized ligand was acting as tetradentate chelating agent and coordinated to metal centre via deprotonated phenolate oxygen and azomethine-N atom. The biological activity of ligand and its metal complexes were screened in vitro against Gram-negative bacteria (Salmonella typhimurium and E. coli), Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and fungus (Aspergillus fumigatus) to ascertain their antibacterial and antifungal properties.