Spectroscopic Characterization and In Vitro Antibacterial Activity of Some Novel Metal Complexes With Schiff Base Ligands Derived From Thiosemicarbazide

Author(s):  
D. Sakthilatha ◽  
A. Deepa ◽  
R. Rajavel
2010 ◽  
Vol 75 (8) ◽  
pp. 1075-1084 ◽  
Author(s):  
Muhammad Imran ◽  
Mitu Liviu ◽  
Shoomaila Latif ◽  
Zaid Mahmood ◽  
Imtiaz Naimat ◽  
...  

The condensation reactions of biacetyl with orthohydroxyaniline and 2-aminobenzoic acid to form bidendate NO donor Schiff bases were studied. The prepared Schiff base ligands were further utilized for the formation of metal chelates having the general formula [ML2.2H2O] where M = Co(II), Ni(II), Cu(II) and Zn(II) and L = HL1 and HL2. These new compounds were characterized by conductance measurements, magnetic susceptibility measurements, elemental analysis, and IR, 1H-NMR and electronic spectroscopy. Both Schiff base ligands were found to have a mono-anionic bidentate nature and octahedral geometry was assigned to all metal complexes. All the complexes contained coordinated water which was lost at 141-160 ?C. These compounds were also screened for their in-vitro antibacterial activity against four bacterial species, namely; Escherichia coli, Staphylococcus aureus, Salmonella typhi and Bacillus subtillis. The metal complexes were found to have greater antibacterial activity than the uncomplexed Schiff base ligands.


Author(s):  
AMAL M ALOSAIMI ◽  
INES EL MANNOUBI ◽  
SAMI A ZABIN

Objective: This work aimed at synthesizing tridentates asymmetrical Schiff base ligands containing sulfur atom and using them for preparing metal complexes with the iron triad metals. The prepared compounds were assayed in vitro for antimicrobial potential and in vivo molluscicidal activity. Methods: The unsymmetrical tridentate Schiff bases (SL1, SL2, and SL3) were prepared using 2-aminothiophenol as primary amine and condensed with 2-carboxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, and 7-formyl-8-hydroxyquinoline. These ligands were used in preparing metal complexes with iron triad metals. The synthesized Schiff base ligands and their corresponding metal complexes were characterized and their proposed structures were confirmed using different physical and spectroscopic analytical techniques. All ligands and their corresponding metal complexes were assayed against different bacterial and fungal strains using the agar disk-diffusion technique. The molluscicidal activity was performed according to the standard reported methods as cited in the literature and by observing the toxicity and lethal dose according to the WHO guidelines. Results: The synthesized ligands behave as tridentate (NOS) ligands and form mononuclear complexes with the general formula [M(SL)2] with an octahedral geometry around the central metal ion. Metal complexes were non-electrolytic in nature. The in vitro antibacterial and antifungal examination results showed weak activity of the ligands, and there was enhanced activity with the complexes. The in vivo molluscicidal activity of the tested compounds showed good activity. Conclusion: The targeted compounds were prepared successfully, characterized, and showed some biological activity but lower than the standard reference drugs.


2013 ◽  
Vol 3 (5) ◽  
pp. 367-370 ◽  
Author(s):  
Waleed Mahmoud Al Momani ◽  
Ziyad Ahmed Taha ◽  
Abdulaziz Mahmoud Ajlouni ◽  
Qasem Mohammad Abu Shaqra ◽  
Muaz Al Zouby

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Narendra Kumar Chaudhary ◽  
Parashuram Mishra

A novel Schiff base ligand of type HL was prepared by the condensation of amoxicillin trihydrate and nicotinaldehyde. The metal complexes of Co+2, Ni+2, Cu+2, and Zn+2 were characterized and investigated by physical and spectral techniques, namely, elemental analysis, melting point, conductivity, 1H NMR, IR, UV-Vis spectra, ESR, SEM, and mass spectrometry measurements. They were further analyzed by thermal technique (TGA/DTA) to gain better insight about the thermal stability and kinetic properties of the complexes. Thermal data revealed high thermal stability and nonspontaneous nature of the decomposition steps. The Coats-Redfern method was applied to extract thermodynamic parameters to explain the kinetic behavior. The molar conductance values were relatively low, showing their nonelectrolytic nature. The powder XRD pattern revealed amorphous nature except copper complex (1c) that crystallized in the triclinic crystal system. The EPR study strongly recommends the tetrahedral geometry of 1c. The structure optimization by MM force field calculation through ArgusLab 4.0.1 software program supports the concerned geometry of the complexes. The in vitro antibacterial activity of all the compounds, at their two different concentrations, was screened against four bacterial pathogens, namely, E. coli, P. vulgaris, K. pneumoniae, and S. aureus, and showed better activity compared to parent drug and control drug.


2011 ◽  
Vol 8 (s1) ◽  
pp. S245-S252 ◽  
Author(s):  
Praveen S. Mane ◽  
Sanjiv M. Salunke ◽  
Balagi S. More

The solid complexes of Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) with Schiff base ligands derived from heterocyclic compounds 3-acetyl-6-methyl-(2H)-pyran-2,4(3H)-dione (Dehydroacetic acid) ando-chloroaniline were synthesized and characterized by elemental analysis, conductance, magnetic, thermal, UV-Vis and1H-NMR spectroscopy. The ligand field parameters have been evaluated for Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) complexes which suggest an octahedral geometry for each of them. The magnetic moment and spectral data suggest the dimeric nature of Mn(II) complexes with octahedral geometry. The fungicidal activities of the ligands and their metal complexes have been screened in vitro againstAspergillus nigerand the percentage inhibition of the metal complexes is found to be increased considerably then that of their corresponding ligands and the order is Cu>Ni>Fe>Mn>Co.


2006 ◽  
Vol 71 (7) ◽  
pp. 733-744 ◽  
Author(s):  
R. Nair ◽  
A. Shah ◽  
S. Baluja ◽  
S. Chanda

Two Schiff bases were synthesized from raceacetophenone: 1) ADS1 4-ethyl-6-{(E)-1-[(3-nitrophenyl)imino]ethyl}benzene-1,3-diol and 2) ADS3 4-ethyl-6-[(E)-1-{(2-nitrophenyl)imino]ethyl}benzene-1,3-diol. Then their metal complexes were formed. The metals selected for the preparation of complexes were copper, nickel, iron and zinc. Hence, in total 8 metal complexes were synthesized and screened for antibacterial activity against some clinically important bacteria, such as Pseudomonas aeruginosa, Proteus vulgaris, Proteus mirabilis, Klebsiella pneumoniae and Staphylococcus aureus. The in vitro antibacterial activity was determined by the Agar Ditch technique using DMF (polar) and 1,4-dioxane (non polar) as solvents. The Schiff bases showed greater activity than theirmetal complexes; themetal complexes showed differential effects on the bacterial strains investigated and the solvent used, suggesting that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. The Schiff base ADS3 in the polar solvent DMF showed better antibacterial activity towards the investigated bacterial strains. Amongst the four metals, Zn showed the best antibacterial activity followed by Fe in 1,4-dioxane while Ni followed by Zn and Fe showed the best antibacterial activity in DMF. P. vulgaris was the most resistant bacteria.


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