scholarly journals Synthesis, Characterization and Antimicrobial studies of Schiff base Ligand from amino acid L-arginine and its Cu(II), Ni(II),Co(II) complexesIJCTR.2019.130201

2020 ◽  
Vol 13 (2) ◽  
pp. 1-8
Author(s):  
R.K. Sree Devi ◽  
S. SudhaKumari

Transition metal complexes of Cu(II), Ni(II), Co(II) with a Schiff base Ligand (R,Z)-2-(2-hydroxy-3-methoxybenzylideneamino)-5-guanidinopentanoic acid (HMA-GPA) was synthesized by the condensation of 2-hydroxy-3-methoxybenzaldehyde and L- Arginine. These were characterized by elemental analysis IR, UV, magnetic susceptibility and molar conductivity measurements. The IR spectra of the Ligand HMA-GPA and the metal complexes suggest that the Ligand coordinates the metal ion through azomethine nitrogen, carboxylate Oxygen and Oxygen of the phenolic -OH group. The electronic absorption spectra and magnetic data indicate the Cu(II), Ni(II)complexes to be square planar and Co(II) complex to be octahedral. The metal complexes and the ligand were subjected to antimicrobial studies by Kirby Bayer Disc-diffusion method and found to have significant activity against the selected bacterial and fungal strains under study.

2012 ◽  
Vol 9 (1) ◽  
pp. 389-400 ◽  
Author(s):  
B. Anupama ◽  
M. Padmaja ◽  
C. Gyana Kumari

A new series of transition metal complexes of Cu(II),Ni(II),Co(II), Zn(II) and VO(IV) have been synthesized from the Schiff base ligand (L) derived from 4-amino antipyrine and 5- bromo salicylaldehyde. The structural features of Schiff base and metal complexes were determined from their elemental analyses, thermogravimetric studies, magneticsusceptibility, molar conductivity, ESI-Mass, IR, UV-VIS,1H NMR and ESR spectral studies. The data show that the complexes have composition of ML2type. The UV-VIS, magnetic susceptibility and ESR spectral data suggest an octahedral geometry around the central metal ion. Biological screening of the complexes reveals that the Schiff base transition metal complexes show significant activity against microorganisms. Binding of Co(II) complex with calf thymus DNA (CT DNA) was studied by spectral methods.


Author(s):  
E. Vijaya Sekhar ◽  
Subhas S. Karki ◽  
Javarappa Rangaswamy ◽  
Mahesh Bhat ◽  
Sujeet Kumar

Abstract Background Sulfonamides (sulfa drugs) and the metals like mercury, copper, and silver bear antimicrobial properties. The discovery of broad-spectrum antibiotics such as penicillins, cephalosporins, and fluoroquinolones has reduced their use. However, in some instances these drugs are the first-line treatment. The metal-based sulfonamide (e.g., silver sulfadiazine) is considered as first choice treatment in post-burn therapy while the use of silver nanoparticle-cephalexin conjugate to cure Escherichia coli infection explains the synergistic effect of sulfa drugs and their metal conjugates. With growing interest in metal-based sulfonamides and the Schiff base chemistry, it was decided to synthesize sulfonamide Schiff base metal complexes as antioxidant and antimicrobial agent. Results The Fe (III), Ru (III), Co (II), Ni (II), Cu (II), Pd (II), Zn (II), Cd (II), and Hg (II) metal complexes of 4-((thiophen-2-ylmethylene)-amino)-benzenesulfonamide (TMABS) were prepared and studied for thermal stability, geometry, and other electronic properties. The ligand TMABS (Schiff base) and its metal complexes were screened in-vitro for 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and antimicrobial properties against Gram-positive (+ve) Bacillus subtilis (MTCC-441), Staphylococcus aureus (MTCC 7443), Gram-negative (-ve) Escherichia coli (MTCC 40), Salmonella typhi (MTCC 3231), and fungal strains Aspergillus niger (MTCC-1344) and Penicillium rubrum by agar well diffusion method. Results summarized in Tables 3, 4, and 5 represent the inhibitory concentration (IC50) in micromole (μM). The zone of inhibition (ZI) in millimeter (mm) represents antimicrobial properties of TMABS and its metal complexes. Conclusions The synthesized sulfanilamide Schiff base (TMABS) behaved as a neutral and bidentate ligand coordinating with metal ions through its azomethine nitrogen and thiophene sulfur to give complexes with coordination number of 4 and 6 (Fig. 3). The nucleophilic addition of sulfanilamide amino group (–NH2) group to carbonyl carbon (>C=O) of benzaldehyde gave sulfanilamide Schiff base (imine) (Fig. 2). All the metal complexes were colored and stable at room temperature. With IC50 of 9.5 ± 0.1 and 10.0 ± 0.7 μM, the Co, Cu, and Pd complexes appeared better antioxidant than the ligand TMABS (155.3±0.1 μM). The zone of inhibition (ZI) of Hg (28 mm) and Ru complexes (20 mm) were similar to the ligand TMABS (20 mm) against Aspergillus niger (MTCC-1344) as in Figs. 4, 5, and 6. None of the synthesized derivatives had shown better antimicrobial properties than the standard streptomycin sulfate and fluconazole.


2017 ◽  
Vol 14 (1) ◽  
pp. 135-147
Author(s):  
Baghdad Science Journal

The free Schiff base ligand (HL1) is prepared by being mixed with the co-ligand 1, 10-phenanthroline (L2). The product then is reacted with metal ions: (Cr+3, Fe+3, Co+2, Ni+2, Cu+2 and Cd+2) to get new metal ion complexes. The ligand is prepared and its metal ion complexes are characterized by physic-chemical spectroscopic techniques such as: FT-IR, UV-Vis, spectra, mass spectrometer, molar conductivity, magnetic moment, metal content, chloride content and microanalysis (C.H.N) techniques. The results show the formation of the free Schiff base ligand (HL1). The fragments of the prepared free Schiff base ligand are identified by the mass spectrometer technique. All the analysis of ligand and its metal complexes are in good agreement with the theoretical values indicating the purity of Schiff base ligand and the metal complexes. From the above data, the molecular structures for all the metal complexes are proposed to be octahedral


2020 ◽  
Vol 85 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Palaniswamy Venkittapuram ◽  
Mahalakshmi Dhandapani ◽  
Jonekirubavathy Suyambulingam ◽  
Chitra Subramanian

A Schiff base ligand L was synthesized by condensation of 1,2-diaminoethane with creatinine. The reaction of the ligand with metal chloride salt gives Co(II) and Cu(II) complexes. The synthesized ligand and its metal complexes were characterized by elemental analysis, FT-IR, NMR, UV?Vis, conductivity and magnetic susceptibility measurements as well as thermal analyses. Based on spectral data, tetrahedral geometries have been proposed for the Co(II) and Cu(II) complexes. The molar conductivity data show that the complexes are non-electrolytic in nature. In DFT studies, the geometry of the Schiff base ligand and its Co(II) and Cu(II) complexes were fully optimized using the B3LYP functional together with 6-31g(d,p) and LANL2DZ basis sets. The ligand and its metal complexes were tested against four bacterial species and two fungal species. The results revealed that the metal complexes are more potent against the microbes than the parent ligand.


2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
F. K. Ommenya ◽  
E. A. Nyawade ◽  
D. M. Andala ◽  
J. Kinyua

A new series of Mn (II), Co (II), Ni (II), Cu (II), and Zn (II) complexes of the Schiff base ligand, 4-chloro-2-{(E)-[(4-fluorophenyl)imino]methyl}phenol (C13H9ClFNO), was synthesized in a methanolic medium. The Schiff base was derived from the condensation reaction of 5-chlorosalicylaldehyde and 4-fluoroaniline at room temperature. Elemental analysis, FT-IR, UV-Vis, and NMR spectral data, molar conductance measurements, and melting points were used to characterize the Schiff base and the metal complexes. From the elemental analysis data, the metal complexes formed had the general formulae [M(L)2(H2O)2], where L = Schiff base ligand (C13H9ClFNO) and M = Mn, Co, Ni, Cu, and Zn. On the basis of FT-IR, electronic spectra, and NMR data, “O” and “N” donor atoms of the Schiff base ligand participated in coordination with the metal (II) ions, and thus, a six coordinated octahedral geometry for all these complexes was proposed. Molar conductance studies on the complexes indicated they were nonelectrolytic in nature. The Schiff base ligand and its metal (II) complexes were tested in vitro to evaluate their bactericidal activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus typhi) using the disc diffusion method. The antibacterial evaluation results revealed that the metal (II) complexes exhibited higher antibacterial activity than the free Schiff base ligand.


2020 ◽  
Vol 3 (3) ◽  
pp. 212-220
Author(s):  
T. Vadivel ◽  
M. Dhamodaran ◽  
S. Kulathooran ◽  
M. Kavitha ◽  
K. Amirthaganesan

Background: The transition metal complexes are derived from a natural biopolymer which is a very potent material in various research areas of study. Objective: This study aims to show the preparation of ruthenium(III) complexes from chitosan Schiff base ligand for effective application in antifungal studies. Methods: Chemical modification was carried out through a condensation reaction of chitosan with some aromatic aldehydes, which resulted in the formation of a bidentate Schiff base ligand. The Ru(III) complexes were prepared by complexation of ruthenium metal ion with bidentate ligands. The series of Ru(III) complexes were characterized by Scanning Electron Microscope with Electron dispersive X-ray (SEM-EDX) analysis, Powder XRD. The biopolymer-based transition metal complexes have potential uses for their biological activities. The synthesized metal complexes were directed for antifungal study by the disc diffusion method. Results: The antifungal study results showed that the transition metal complexes have significant antifungal activities against some vital fungal pathogens such as Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Penicillim chryogenum and Trigoderma veride. Conclusion: A chitosan biopolymer offers some peculiar features such as biodegradability, biocompatibility etc., which are favorable for green synthesis of transition metal complexes through complexation with bidentate ligands. These metal complexes possess good antifungal property due to their chelation effect on micro-organisms.


2012 ◽  
Vol 9 (4) ◽  
pp. 2119-2127 ◽  
Author(s):  
Gajendra Kumar ◽  
Rajeev Johari ◽  
Shoma Devi

A Schiff base ligand was synthesized by reacting 5-tert-butl-2-hydroxy-3-(3-phenylpent-3-yl) benzaldehyde and thiodihydrazide (2:1) and a series of metal complexes with this new ligand were synthesized by reaction with Cr (III), Mn (III), and Fe (III) metal salt in methanolic medium. The Schiff base ligand and its complexes have been characterized with the help of elemental analysis, conductance measurements, magnetic measurements and their structure configuration have been determined by various spectroscopic (electronic, IR,1H NMR,13C NMR, GCMS) techniques. Electronic and magnetic moments of the complexes indicate that the geometries of the metal centers were octahedral. IR spectral data suggest that ligand behaves as a tetradentate ligand with ONNO donor sequence towards the metal ion.


Author(s):  
R. Govindharaju ◽  
P. Durairaj ◽  
T. Maruthavanan ◽  
M. Marlin Risana ◽  
T. Ramachandramoorthy

Cr(III) and Mn(II) metal complexes of Schiff base ligand derived from phenylacetylurea condensed with salicylaldehyde (SBPS) and thiocyanate(SCN-) ion were synthesized by using microwave irradiation. Microwave assisted synthesis gives high yield of the complexes within a very short time. The molecular formulae and the geometry of the complexes have been deduced from elemental analysis, metal estimation, electrical conductance, magnetic moment, electronic spectra, FT- IR, Far IR spectra, cyclic voltammetry, thermal analysis and powder-XRD techniques. The molar conductance values indicate that the complexes are non-electrolyte (1:0) type. FT-IR spectra show that Schiff base and thiocyanate ion are coordinated to the metal ion in a monodentate manner. The electronic spectra and the magnetic moment indicate the geometry of the complexes is found to be octahedral. The antimicrobial activities of ligands and their Cr(III) and Mn(II) complexes were studied against the microorganisms, viz., E. coli, Klebsiella Pneumonia, P. aeruginosa, S. aureus, Bacillus cereus, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Aspergillus sojae and Candida albicans by agar well diffusion method. The complexes show moderate activity against the bacteria and enhanced activity against the fungi as compared to free SBPS ligand. The free radical scavenging activity of the complexes and the ligands has been determined by measuring their interaction with the stable free radical, DPPH. The complexes have larger antioxidant activity as compared to the ligand. DNA-binding properties have been studied by fluorescence-emissions method. The results suggest that the complexes strongly bind to DNA because of metal complexes are well-known to speed up the drug action and the ability of a therapeutic agent which can frequently be enhanced upon coordination with a metal ion.


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