STRUCTURAL ELUCIDATION, BIOASSAY AND PYROLYTIC CHARACTERIZATION OF COORDINATION COMPOUNDS WITH NOVEL SCHIFF’s BASES

Abstract

This research work was planned to synthesize and characterize transition metal complexes of some biologically active Schiff base chelating agent and then to investigate their antimicrobial and antioxidant activities. The ligands (L1-L5) are the modified forms of pyridine-3-carbaldehyde containing azomethine linkage which is of considerable importance in coordination chemistry. All the ligands were synthesized by reacting pyridine-3-carbaldehyde with primary amines. The structure of the newly synthesized amines were established by IR, NMR, Mass and elemental analysis. The ligands formed complexes of the type [MLX 2 ]. The comparison of the IR spectra of ligands and their metal complexes suggested that pyridine-3-carbaldehyde-N and amine-N are involved in the coordination with the metal ions. The UV-visible spectra of the complexes indicated the tetrahedral geometry for Co(II), Ni(II), Cu(II) and Zn(II) complexes. The antibacterial and antifungal activities of all the compounds were tested against the gram negative bacteria Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa, gram positive bacteria Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumonia and fungal strains Aspergillus Fumigatus, Aspergillus Flavus and Fusarium Solani. Antioxidant activities including Free Radical Scavenging Assay, Nitric Oxide Scavenging Activity, Hydroxyl Radical (OH) Scavenging Activity and Reducing Power were also carried out. Thermal stability of the compounds was studied through TG/DTA.