scholarly journals Synthesis, Spectral Characterization and Pharmacological Significance of Cr(III) and Mn(II) Complexes with Schiff Base and Thiocyanate Ion as Ligands

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.

Author(s):  
M. Marlin Risana ◽  
S. Balasubramaniyan ◽  
R. Govindharaju ◽  
V. Mukil Meenakshi ◽  
B. Jayalakshmi ◽  
...  

New Cobalt(II) and Nickel(II) metal complexes of 2-aminothiazole (ATZ) and benzoate ion (BEN) ligands were  synthesized under microwave irradiation. The empirical formulae and the structure of the complexes have been deduced from CHN analysis, electrical conductance, magnetic moment, electronic (DRS method), Infra Red spectra, TGA analysis, cyclic voltammetry and powder-XRD techniques. The low electrical conductance values indicate that the complexes are non-electrolyte (1:0) type. The electronic spectra and the magnetic moment indicate the structures of the complexes are found to be octahedral geometry. Infra Red spectra illustrate that 2-aminothiazole and benzoate ion is bonded to the metal ion in a monodentate approach. The antifungal activities of ligands and their cobalt(II) and nickel(II) metal complexes were studied aligned with the few microorganisms by agar - well diffusion method at 100,200 and 400 conc. µg/ml concentration.  The prepared cobalt(II) and nickel(II) metal complexes show prospective action against the tested fungi as compared to free 2-aminothiazole ligand. The free radical scavenging action of the prepared complexes and the ligand has been resolute by measuring their interface with the stable free radical DPPH. The complexes have larger antioxidant activity as compared to the free ligand. DNA-binding properties have been calculated by fluorescence-emissions method. The obtained results suggest that the complexes powerfully bind to DNA because of metal complexes are well-known to speed up the drug action and the capability of healing agent which can repeatedly be enhanced leading coordination with a metal ion.


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.


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.


2011 ◽  
Vol 699 ◽  
pp. 273-279
Author(s):  
A. Xavier ◽  
R Sathya ◽  
D. Usha ◽  
P.S. Harikrishnan

A series of metal complexes have been synthesized by the reaction of Schiff base with metal (II) salt solution. The complexes were characterized by UV and FT- IR studies. The study reveals that the geometry of the complexes were octahedral. The electronic spectra of these complexes show a strong absorption band in 550 – 580 nm region. This confirms the coordination of ligand with metal. The FT-IR shows a very strong band at 1606cm-1 assigned to C=N stretching vibration. It is shifted to lower wave number because of the complex formation, suggesting that coordination of the Schiff base groups through N- atoms with the metal ion. The band at 3056cm-1 is due to aromatic O-H stretching, the sharp peak at 750 cm-1 and 688 cm-1 are due to halogens substituted in the para position.


2011 ◽  
Vol 474-476 ◽  
pp. 543-547
Author(s):  
Ti Feng Jiao ◽  
Juan Zhou ◽  
Jing Xin Zhou ◽  
Yuan Yuan Xing ◽  
Xu Hui Li

A novel glycine-based Schiff base derivative (abbreviated as C16GlySb) containing long alkyl chain was synthesized from glycine reacted with 4-cetyloxy-2-hydroxybenzaldehyde and sequentially coordinated with various metal ions to give the corresponding metal complexes (abbreviated as G-M). The products were characterized by UV-Vis spectra and FT-IR spectra. At the same time, the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group, oxygen atom in phenolic hydroxyl group, and carboxylic ion participated in coordinating with transition metal ion in doubly-bridged mode. UV spectra showed that compared with ethanol solution, the cast film on quartz plate showed H-type or J-type aggregate structure. In addition, the thermal stability of G-M had been obviously superior to that of the ligand C16GlySb. The present results have showed potential application in fields of functional material and catalyst.


2011 ◽  
Vol 699 ◽  
pp. 265-271 ◽  
Author(s):  
A. Xavier ◽  
R Sathya ◽  
D. Usha ◽  
P.S. Harikrishnan

A series of metal complexes have been synthesized by the reaction of Schiff base with metal (II) salt solution. The complexes were characterized by UV and FT- IR studies. The study reveals that the geometry of the complexes were octahedral. The electronic spectra of these complexes show a strong absorption band in 550 - 580nm region. This confirms the coordination of ligand with metal. The FT-IR shows a very strong band at 1616cm-1assigned to C=N stretching vibration. It is shifted to lower wave number because of the complex formation, suggesting that coordination of the Schiff base groups through N- atoms with the metal ion. The band at 3496 cm-1is due to aromatic N-H stretching, It is noted that a broad band of the asymmetric and symmetric O-H stretching mode around the region 3400 cm-1presumably due to H-O-H bending vibrations are not observed in the spectrum of complexes, which are indicating of the absence of the water molecule.


2021 ◽  
Vol 33 (12) ◽  
pp. 3063-3069
Author(s):  
Abhay Nanda Srivastva ◽  
Sayanwita Panja ◽  
Netra Pal Singh ◽  
Chandra Kiran Shriwastaw

A novel series of trivalent coordination complexes was synthesized by the reaction between a chloride/ acetate salt of iron, chromium, cobalt or manganese ions and NNNNOO type persuasive Schiff base ligand synthesized from 2,3-dioxobutane, ethane-1,2-diamine and 4-chloro-2-formylphenol. Synthesized compounds were characterized by using elemental analysis, molar conductance, magnetic moment, IR, UV-visible, 1H NMR, 13C NMR and ESI-MS spectral analyses. IR and NMR spectra favoured hexadentate coordination behaviour of ligand. Electronic spectra and magnetic moment data reveal Oh geometry with distortion around the metal ion in complexes. The molar conductance values show 1:1 electrolytic nature of complexes. Biological potentiality of the ligand and its metal complexes were tested in vitro against two bacterial and two fungal strains; Bacillus subtilis, Escherichia coli and Aspirgillus niger, Aspirgillus flavus, respectively.


2011 ◽  
Vol 474-476 ◽  
pp. 1523-1528
Author(s):  
Ti Feng Jiao ◽  
Jian Liu ◽  
Li Hua Gao ◽  
Jing Xin Zhou ◽  
Yuan Yuan Xing

Two aromatic Schiff base derivatives and the corresponding metal complexes with different substituted groups were synthesized and characterized by many methods. The products were characterized by UV-Vis spectra, FT-IR spectra and thermal analysis, while the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group and oxygen atom in phenolic hydroxyl group participated in coordinating with transition metal ion in different bridged mode. UV spectra also verified that different coordination modes can be performed between metal ions and ligands. In addition, the thermal stability of metal complexes had been obviously superior to that of the ligands. All results give a useful clue to obtain Schiff base derivatives with versatile property by regulating intramolecular substituted group and species of metal ion. The present results have showed potential application in fields of functional material and catalyst.


2021 ◽  
Vol 33 (6) ◽  
pp. 1222-1228
Author(s):  
R. Selvarani ◽  
S. Balasubramaniyan ◽  
K. Rajasekar ◽  
M. Thairiyaraja ◽  
R. Meenakshi

A new bidentate Schiff base (E)-N′[(E)-3-phenylallylidene]benzene-1,2-diamine derived from the condensation of o-phenylenediamine and cinnamaldehyde and its Mn(II) and Hg(II) complexes were synthesized and characterized by elemental analysis, molar conductance, magnetic moment, electronic spectra, IR, far-IR and NMR (1H & 13C) spectral studies. The elemental analysis and these metal proposed the metal:ligand stoichiometry and molecular formulae of the metal complexes. The molar conductance and electrochemical property indicates monomeric, neutral nature and redox properties of the metal complexes. The UV-visible spectral study supports the octahedral geometry for Mn(II) complex and square planar geometry for Hg(II) complex and further confirmed by magnetic moment. IR spectral data examined the coordination mode but far-IR is useful to identify the metal-ligand vibrations. The geometry, magnetic property and unsymmetrical nature of these metal complexes corroborated by NMR (1H & 13C) spectra. The DFT of Mn(II) complex studied and the structure optimized by B3LYP/Lan L2DZ using Gaussian 09W. Quantum chemical calculations were done by Mullikan population analysis, HOMO-LUMO and molecular electrostatic potential. The in vitro biological screening effects of the investigated complexes were tested against some bacteria and fungus by agar-well diffusion method. The results indicated that Mn(II) and Hg(II) complexes exhibit potentially active than the Schiff base which was further confirmed by pharmacokinetics study. The antioxidant activity of Schiff base and its Mn(II) complex was examined by radical scavenging DPPH method.


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.


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