scholarly journals Synthesis, Spectral Characterization and Antimicrobial Studies of Co(II) Complexes with Tetradentate Schiff bases Derived from Ortho-Phthalaldehyde

2016 ◽  
Vol 9 (1) ◽  
pp. 1873-1882
Author(s):  
V. Sreenivas ◽  
G. Srikanth ◽  
Ch. Vinutha ◽  
M. Shailaja ◽  
P. Muralidhar Reddy ◽  
...  

A series of cobalt (II) complexes have been synthesized with Schiff bases derived from ortho-phthalaldehyde and various amines in aqueous methanol solution. The newly synthesized Schiff bases and their Co (II) complexes have been characterized  by elemental analysis, magnetic susceptibility, thermal, conductance measurements, mass, IR, electronic, 1H,13C-NMR spectral techniques. These ligands act as tetradentate species and coordinate to the metal center through the different potential donor atoms such as N, O and S. The probable octahedral structures have been assigned to these complexes. All the synthesized Schiff base ligands and Co(II) metal complexes have also been screened for their antimicrobial activities and metal complexes found to be more active than respective Schiff-base ligands.

Author(s):  
Deeksha Sharma ◽  
Prof. Arpan Bhardwaj

In the present paper, synthesis of Schiff base ligands and the metal complexes are studied and compared by conventional and solvent free route. The synthesis of Schiff base ligands of amino acids (Glycine, Phenylalanine and Tyrosine) with salicylaldehyde and their mixed ligand ternary Cu(II) complexes are discussed. Other ligands are used in co-ordinaion with the schiff base is 1,10- Phenanthroline/thiourea  in equimolar ratio. The environmentally efficient and modern developed method for synthesis is the solid state synthesis of salicylidene amino acids through pestle mortar synthetic procedure. This method is compared with the conventional method that require refluxing the reactant mixture for hours in an organic solvent, here ethanol. The complexes are characterized by spectral techniques IR spectroscopy and UV spectroscopy. The investigations concluded that the pestle mortar assisted method is very rapid , simple and economic for the preparation of  ligands and complexes as well. The Antimicrobial studies were also performed for the complexes. The spectral data for the ligands and complexes obtained from either method, conventional and solventless procedure are in good agreement with one another. The azomethine bonding(-CH=N-) between salicylaldehyde amino acids based Schiff bases is described by the IR spectral peak around 1600 cm-1.                                      


2020 ◽  
Vol 41 (1) ◽  
pp. 26-35
Author(s):  
Kishor Devkota ◽  
Govinda Pathak ◽  
Bhushan Shakya

Triazole ring system has attracted a continuously growing interest of synthetic organic chemists and those dealing with the medicinal compounds due to its versatile potential to interact with biological systems. Schiff bases are also considered as one of the most biologically active compounds.  The aim of the present study was to synthesize new Schiff bases bearing triazole nucleus and to assess their antimicrobial activities. Four new Schiff base derivatives of 1,2,4-triazole-3-thione were synthesized by combining two different pharmacophores viz. triazole nucleus and Schiff base moiety and were characterized by spectral techniques (UV, FT-IR, and NMR). The Schiff bases were evaluated for antibacterial (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and antifungal (Candida albicans) activities. The synthesized compounds exhibited good to moderate activities against different strains of bacteria and fungi tested.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
K. R. Joshi ◽  
A. J. Rojivadiya ◽  
J. H. Pandya

Two new series of copper(II) and nickel(II) complexes with two new Schiff base ligands 2-((2,4-dimethylphenylimino)methyl)-6-methoxy-4-nitrophenol and 2-((3,4-difluorophenylimino)methyl)-6-methoxy-4-nitrophenol have been prepared. The Schiff base ligands were synthesized by the condensation of 2-hydroxy-3-methoxy-5-nitrobenzaldehyde with 2,4-dimethylaniline or 3,4-difluoroaniline. The ligands and their metal complexes have been characterized by IR, 1H NMR, mass and electronic spectra and TG analysis. The Schiff base ligands and their metal complexes were tested for antimicrobial activity against Gram positive bacteria Staphylococcus aureus, and Streptococcus pyogenes and Gram negative bacteria Escherichia coli, and Pseudomonas aeruginosa and fungus Candida albicans, Aspergillus niger, and Aspergillus clavatus using Broth Dilution Method.


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.


2019 ◽  
Vol 84 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Chinnaraj Kanagavalli ◽  
Murugesan Sankarganesh ◽  
Raja Dhaveethu ◽  
Manivannan Kalanithi

Novel series of Co(II), Ni(II) and Cu(II) transition metal complexes were synthesized from the Schiff base ligands HL1?HL4 derived from 2-amino-6- nitrobenzothiazole with various aromatic aldehydes, i.e., 4-methylbenzaldehyde, 4- ethylbenzaldehyde, 2-hydroxybenzaldehyde and 4-hydroxybenzaldehyde, respectively. The ligands HL1?HL4 and their metal (II) complexes were characterized by atomic absorption spectroscopy (AAS), magnetic susceptibility and molar conductance measurements, and UV?Vis, FT-IR and NMR spectroscopic techniques. The spectroscopic studies revealed that the complexes of HL1?HL3 coordinated in an octahedral environment and L4 in square planar/tetrahedral geometry. The ligands HL1?HL4 and their metal(II) complexes were screened for their antimicrobial activities against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The results suggest that the complexes of HL4 possess greater inhibition activity towards C. albicans. The nonlinear optics (NLO) activities of ligands HL1?HL4 were determined. The obtained results showed that ligands HL1 and HL2 have greater second harmonic generation (SHG) efficiency than HL3and HL4.


Author(s):  
Charity W. Dikio ◽  
Ikechukwu P. Ejidike ◽  
Fanyana M. Mtunzi ◽  
Michael J. Klink ◽  
Ezekiel D. Dikio

Objective: The study was focused on the synthesis and spectroscopic studies of metal acetylacetonates and their complexes using bidentate Schiff-base ligands (NO), evaluation of their in-vitro antibacterial potentials against pathogenic microorganism.Methods: Acetylacetonate salts of Cobalt(II), Manganese(II) and Magnesium(II) were prepared by reacting their metal hydroxides with acetylacetone. The metal complexes of N'-{(E)-[4-(diethylamino)-2-hydroxyphenyl]methylidene}-4-nitrobenzohydrazide (HL1), N'-{(E)-[4-(diethylamino)-2-hydroxyphenyl]methylidene}-4-methoxybenzohydrazide (HL2) obtained from the condensation reaction of 4-(diethylamino)-2-hydroxybenzaldehyde and 4-nitrobenzohydrazide/ or 4-methoxybenzohydrazide. The synthesized compounds were characterized by fourier transform infrared spectroscopy (FT-IR), proton and carbon-13 nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA). The compounds were screened for their antimicrobial properties against a list of Gram-positive bacterial strains.Results: The FT-IR spectra revealed that the Schiff bases acts as bidentate chelating ligand via nitrogen of the azomethine and phenolic oxygen atoms. NMR reveal the presence of azomethine (HC=N) and aromatic hydrogens at expected chemical shifts confirming the formation of the Schiff base ligands. Thermal decomposition behaviour was studied by thermogravimetry revealing stability up to 260 °C. The compounds were evaluated for their antibacterial potentials against Staphylococcus aureus and Enterococcus faecalis. The manganese acetylacetonato(N'-{(E)-[4-(diethylamino)-2-hydroxyphenyl]methylidene}-4-methoxybenzohydrazide: Mn(acac)(L2) exhibited antimicrobial activities against both Enterococcus faecalis and Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 398.0 μg/mL.Conclusion: The prepared compounds showed no inhibition against the selected pathogenic microorganisms except for Mn(acac)(L2) Standard antibacterial compounds: ampicillin and ciprofloxacin were used as positive control. The antibacterial activity of the compound depends on the kind of substituent on the benzo hydrazide rings at the para position, thereby suggesting the compound as promising chemotherapeutic agents for further structural optimization. 


2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Ramasamy Jayarajan ◽  
Gnanasambandam Vasuki ◽  
Pillutla Sambasiva Rao

Synthesis, characterization, and antimicrobial activity of tridentate Schiffbase ligands containing pyrazolone moiety (3a and 3b) and their transition metal complexes of VO(II), Cu(II), Fe(III), and Co(II) 4a–h have been investigated. The complexes show enhanced antibacterial activity against S. aureus, E. coli, and S. typhi and antifungal activity against C. albicans, Rhizopus sp., and A. niger compared to the ligands.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ramesh S. Yamgar ◽  
Y. Nivid ◽  
Satish Nalawade ◽  
Mustapha Mandewale ◽  
R. G. Atram ◽  
...  

The synthesis and antimicrobial activity of novel Zn(II) metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z)-{[3-(N-methylamino)propyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E)-{[4-(1H-1,2,4-triazol-1-ylmethyl)phenyl]imino}methyl]phenol, and (4S)-4-{4-[(E)-(2-hydroxybenzylidene)amino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria:E. coliandPseudomonas fluorescens, Gram positive bacteria:Staphylococcus aureus,and also against fungi, that is,C. albicansandA. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2 μg/mL). The “in vitro” data has identified [Zn(NMAPIMHMC)2]·2H2O, [Zn(TMPIMP)2]·2H2O, and [Zn(HBABO)2]·2H2O as potential therapeutic antifungal agents againstC. albicansandA. niger.


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