Twelve complexes derived from thiobarbituric acid with Cu, Zn, Co, Fe, Cd and Ni have been prepared and analyzed in the mole ratios 1:1,1:2, 1:3 and 1:4 (M : L). They were characterized by elemental analysis, UV-Vis, IR, 1H-NMR, ESR for Copper complexes, Magnetic Susceptibility and Thermal Analysis (TGA, DTA). The biological activities of thiobarbituric acid and its complexes which are tested against staphylococcus aureus (Gram positive) bacteria, Esherichia coli (Gram negative) bacteria and Candida albicans fungi. The results showed that some of the tested compounds have a well considerable activity against the tested microorganisms. The data of MIC showed that Cu (II) complexes were the most effective antibacterial and antifungal agents compared to the other complexes. 

Keyword: Thiobarbituric acid; Biological Activity; ESR; Magnetic Susceptibility; IR; MIC.