Synthesis, physicochemical and antimicrobial properties of rhenium (I) tricarbonyl complexes of isatin Schiff bases

Abstract

The Schiff base of isatin and sulphanilamide (L1; C 14 H 11 N 3 O 3 S) was prepared and reacted with Re(CO) 5 X (X = Cl and Br) in toluene to give [Re(C 14 H 10 N 2 O)(CO) 3 X] (X = Cl, 1 and X = Br, 2). The prepared Schiff base of isatin and 4-methoxyaniline (L2; C 15 H 12 N 2 O 2 ) was reacted with Re(CO) 5 X in toluene to give [Re(C 14 H 10 N 2 O)(CO) 3 X], where X = Cl, 3 and X = Br, 4. L2 and Re(CO) 5 Br were refluxed in dry toluene under nitrogen and recrystallized to give [Re(C 15 H 12 N 2 O 2 )(CO) 3 Br]. 1 / 2 C 2 H 5 OH (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.

Study of Corrosion Inhibition of Mild Steel in 0.1n Hcl Solution Using 3-[(4-Methoxy Phenyl)Imino]-1,3-Dihydro-2H- Indole-2-One

“…We can see from Fig ( 2) that there is a significant decrease in the corrosion rate and an increase in the inhibition efficiency as the concentration of the inhibitor is increased. This supports that the used inhibitor gets adsorbed on the metal surface and protects it by forming a protective layer [5][6][7].…”

“…The protective layer formed on the metal surface was studied by using Electron dispersion X-ray analysis (EDAX). From Table (6), it can be observed that before immersion of a mild steel sample in 0.1 N HCl solution, the Fe content was around 90%. But after immersion in 0.1 N HCl for 24 hours the Fe content decreased to around 63%.…”

“…The inhibitor MIDI was prepared by following the procedure available in the literature [6]. MIDI was prepared by dissolving 3g of isatin in 120 cm 3 of methanol.…”

“…The inhibition efficiency dropped to 80.35% and 71.87% at 333K and 343K respectively. This suggests that at higher temperatures the used inhibitor gets detached from the metal surface and the dissolution of the inhibitor takes place into the solution, Thus the used inhibitor is no longer protecting the mild steel surface and the surface is exposed to an acidic medium, thus increasing the metal dissolution [5][6][7][8][9][10][11][12][13][14].…”