Abstract

The Schiff base of isatin and sulphanilamide (L1; C₁₄H₁₁N₃O₃S) was prepared and reacted with Re(CO)₅X (X = Cl and Br) in toluene to give [Re(C₁₄H₁₀N₂O)(CO)₃X] (X = Cl, 1 and X = Br, 2). The prepared Schiff base of isatin and 4-methoxyaniline (L2; C₁₅H₁₂N₂O₂) was reacted with Re(CO)₅X in toluene to give [Re(C₁₄H₁₀N₂O)(CO)₃X], where X = Cl, 3 and X = Br, 4. L2 and Re(CO)₅Br were refluxed in dry toluene under nitrogen and recrystallized to give [Re(C₁₅H₁₂N₂O₂)(CO)₃Br].¹/₂C₂H₅OH (5). Spectroscopic characterization of compounds was done using FTIR, UV-Visible, NMR and Mass spectra analyses. Magnetic susceptibility measurements and melting points were also determined. Elemental analysis of 5 revealed it was a solvate molecule of 4. The in-vitro antimicrobial activities of compounds were evaluated against Staphylococcus aureus, Bacillus subtilis, Haemolytic Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella sp., Aspergillus niger, Trichoderma viride and Penicillium citrinum. Spectroscopic analyses revealed new terminal carbonyl bands formed between 1900 and 2030 cm^-1, as L1 and L2 coordinated through their azomethine nitrogen and keto oxygen donor atoms towards Re(I). Results of the antimicrobial studies revealed immerse improved activities upon coordination against tested microorganisms especially gram-negative bacteria, therefore they are recommended for further studies in cell imaging.

Key words: Isatin Schiff bases, rhenium (I) tricarbonyl complexes, antimicrobial, antifungal.