Mn(II), Co(II), Ni(II), and Cu(II) complexes of amino acid derived Schiff base ligand: Synthesis, characterization and in-vitro antibacterial investigations

2021 ◽  
Vol 35 (1) ◽  
pp. 97-106
Author(s):  
A. O. Rajee ◽  
H. F. Babamale ◽  
A. Lawal ◽  
A. A. Aliyu ◽  
W. A. Osunniran ◽  
...  

Four complexes of Mn(II), Co(II), Ni(II) and Cu(II) with Schiff base ligand (H3L) derived from 2-amino-3-methylbutanoic acid and acetylacetonate were synthesized. All complexes were characterized by elemental analysis, Fourier-transform infrared spectroscopy and electronic spectroscopy. The results confirmed the coordination of the ligand to metals in tridentate fashion via the hydroxyl oxygen, the azomethine nitrogen and the enolic acetylacetonate oxygen. Antimicrobial activities were established for all complexes, free ligand and ciprofloxacin for comparison. Both the ligand and its metal complexes were active against Gram-positive and negative bacterial strains. The Cu(II) complex, showed highest antibacterial activity among the complexes screened. Other complexes displayed considerable antibacterial activity. Octahedral geometry was proposed for the metal(II) complexes with the Schiff base.                     KEY WORDS: Schiff base, Amino acid, Metal Complexes, Antibacterial agents   Bull. Chem. Soc. Ethiop. 2021, 35(1), 97-106. DOI: https://dx.doi.org/10.4314/bcse.v35i1.8

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.


2021 ◽  
Vol 11 (1) ◽  
pp. 3249-3260

Herein, we describe the synthesis and characterization of a Schiff base ligand (E)-N'-(2-hydroxybenzylidene)-4-methoxybenzohydrazide (HBMB) and its Mn(II), Ni(II), and Cu(II) metal complexes (C1-C3) respectively. The ligand HBMB was synthesized by reacting condensation of salicylaldehyde and 4-methoxy benzohydrazide in a 1:1 molar ratio. The structure of HBMB and its metal complexes (C1-C3) were evaluated by using UV-Vis, FT-IR, 1H-NMR, mass spectroscopy as well as on the basis of elemental analysis, conductivity measurements, and thermogravimetric techniques (TGA). The synthesized molecules' tumoricidal properties were performed against human breast cancer (MCF-7) and colon cancer (HT 29) cell lines. The biological results indicated that the ligand, HBMB, and metal complexes possess dose-dependent selective cytotoxicity against the tested carcinoma cells. The synthesized compounds were further evaluated for their in vitro antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli), and fungal strains (Aspergillus niger).


2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Aurora Reiss ◽  
Mariana Carmen Chifiriuc ◽  
Emilia Amzoiu ◽  
Cezar Ionuţ Spînu

New [ML2(H2O)2] complexes, where M = Co(II), Ni(II), Cu(II), and Zn(II) while L corresponds to the Schiff base ligand, were synthesized by condensation of cefotaxime with salicylaldehydein situin the presence of divalent metal salts in ethanolic medium. The complexes were characterized by elemental analyses, conductance, and magnetic measurements, as well as by IR and UV-Vis spectroscopy. The low values of the molar conductance indicate nonelectrolyte type of complexes. Based on spectral data and magnetic moments, an octahedral geometry may be proposed for Co(II), Ni(II), and Zn(II) complexes while a tetragonal geometry for Cu(II) complex. Molecular structure of the Schiff base ligand and its complexes were studied using programs dedicated to chemical modeling and quantomolecular calculation of chemical properties. All the synthesized complexes were tested forin vitroantibacterial activity against some pathogenic bacterial strains, namelyEscherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis,andStaphylococcus aureus. The MIC values shown by the complexes against these bacterial strains revealed that the metal complexes possess superior antibacterial activity than the Schiff base.


2019 ◽  
Vol 31 (10) ◽  
pp. 2331-2336 ◽  
Author(s):  
Manoj Kumar ◽  
Anita Rani ◽  
Hardeep Singh Tuli ◽  
Rajshree Khare ◽  
Vinit Parkash

This report describes the synthesis and exploration of novel Schiff base ligand in the form of a polymer (heptamer) which was prepared by reaction between 3,4-diacetyl-2,5-hexanedione and hydrazine hydrate in ethanol. On further reaction of Schiff base with transition metals ions (Co and Cu) leads to formation of its transition metal complexes. The structural identification of Schiff base ligand and its transition metal complexes were characterized by classical structural techniques like FT-IR, NMR and mass spectra. The free ligand and its transition metal complexes have been screened for in vitro biological activities against various strains of bacteria and fungi. The prepared Schiff base and its metal complexes were also screened for antiangiogenic activity. The results have shown the remarkable antimicrobial and antiangiogenic activities of the Schiff base and its metal complexes.


2021 ◽  
Author(s):  
Hanan F. Abd El-Halim ◽  
Gehad Mohamed ◽  
Walaa Mahmoud ◽  
Omnia El-Sayed

Abstract 2,2’-((1Z-1’Z) (1,3-diphenylpropane-1,3-diylidene) bis (azanylylidene)) dibenzoic acid (H2L) Schiff base ligand, was obtained by condensation reaction between anthranilic acid and dibenzoyl methane in 2:1 ratio.A series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes was resulted from 1:1 (ligand: metal salt) reaction.The structural features of the synthesized ligand and its metal complexes was determined by elemental analyses, IR, 1H NMR, UV-Vis, ESR, mass spectra, conductivity and magnetic susceptibility measurements as well as thermal (TG/DTG) analyses. The analytical and spectroscopic tools showed that the complexes had composition of ML type with octahedral geometry. The IR results confirmed the tetradendate binding of the ligand involving two azomethine nitrogen atoms and two carboxylate oxygens. The Schiff base and its complexes have been screened for their antimicrobial activity against several bacterial organisms as (Streptococcus pneumoniae and Bacillus subtilis; Pseudomonas aeruginosa and Escherichia coli) and fungi (Aspergillus fumigatus; Syncephalastrum racemosum; Geotricum candidum and Candida albicans) by disk diffusion method.All the metal complexes have potent antimicrobial activity than the free ligand. Anticancer activity of the ligand and its metal complexes was evaluated against human cancer (MCF-7 cells viability).


2019 ◽  
Vol 32 (1) ◽  
pp. 192-194
Author(s):  
S. Sudha Kumari

In present work, the screening of antimicrobial activities of copper(II) and cobalt(II) complexes with Schiff base ligand derived from the condensation of citral with valine (amino acid) was carried out on agar plates are reported. The antibacterial activity of Schiff base and its copper(II) and cobalt(II) complexes were evaluated against two bacterial strains Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative) and fungus Candida albicans. The results revealed that the Schiff base ligand exhibited the poor antimicrobial activity against Escherichia coli and Candida albicans except for Staphylococcus aureus. Generally, Gram-negative bacteria shows rigid outer membrane, well enough to defend against the drug but Schiff base (citral with valine derived) impregnated cobalt(II) complex seem to be more active against Escherichia coli organisms in comparison to copper(II) complex, which exhibits higher activity than uncomplexed ligand. The antimicrobial results revealed that cobalt(II) and copper(II) complexes have a considerable antibacterial activity than antifungal activity and suggest their potential application as antibacterial agents.


2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.


Author(s):  
B. Akila ◽  
A. Xavier

Schiff base synthesized from 2-hydroxy-1-naphthaldehyde and 2-2’ (ethylene dioxy) bis ethylenediamine (L1) and its Metal complexes, [M (II) (L)6](where M= Mn(II), Ru(III), Cu(II)and V(V) L= Schiff base moiety), have been prepared and characterized by elemental analysis, spectroscopic measurements (infrared, electronic spectroscopy, 1H-NMR, EPR and Mass spectroscopy ). Elemental analysis of the metal complexes was suggested that the stoichiometry ratio is 1:1 (metal-ligand). The electronic spectra suggest an octahedral geometry for MC1and MC2 Schiff base complexes and distorted octahedral for MC3 and MC4 complexes. The Schiff base and its metal chelates have been screened for their invitro test antibacterial activity against three bacteria, gram-positive (Staphylococcus aureus) and gram-negative (Klebsiella pheneuammonia and Salmonella typhi). Two strains of fungus (Aspergillus niger and Candida albicans). The metal chelates were shown to possess more anti fungal activity compare then antibacterial activity and antioxidant properties. The complexes are highly active than the free Schiff-base ligand.    


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
K. Savithri ◽  
B. C. Vasantha Kumar ◽  
H. K. Vivek ◽  
H. D. Revanasiddappa

A bidentate (N- and O-) imine-based ligand (L1) and its metal complexes of types [CuII(L1)2] (C1), [CuII(L1)(Phen)] (C2), [CoIII(L1)2] (C3), and [CoIII(L1)(Phen)] (C4) (L1 = 2-((E)-(6-fluorobenzo[d]thiazol-2-ylimino)methyl)-4-chlorophenol and phen = 1,10-phenanthroline) were synthesized as potential chemotherapeutic drug candidates. The prepared complexes were structurally characterized by spectral techniques (NMR, FT-IR, LC-MS, EPR, and electronic absorption), thermogravimetric analysis (TGA/DTA), magnetic moment, and CHNO elemental analysis. Spectroscopic studies suggested the distorted octahedral structure for all complexes. In vitro bioassay studies include binding and nuclease activities of the ligand and its complexes with target calf thymus- (CT-) DNA were carried out by employing UV-Vis, fluorescence spectroscopy, viscosity, and gel electrophoresis techniques. The extent of binding propensity was determined quantitatively by Kb and Ksv values which revealed a higher binding affinity for C2 and C4 as compared to C1 and C3. In addition, the scavenging superoxide anion free radical (O∙-2) activity of metal complexes was determined by nitroblue tetrazolium (NBT) light reduction assay. Molecular docking studies with DNA and SOD enzyme were also carried out on these compounds. The antimicrobial study has shown that all the compounds are potential antibacterial agents against Gram-negative bacterial strains and better antifungal agents with respect to standard drugs used.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Dorian Polo-Cerón

This paper reports the synthesis and detailed characterisation of copper(II) and nickel(II) complexes with tridentate thiosemicarbazone ligands H2L1 and H2L2 derived from 2-acetylpyrazine. The ligands and their metal complexes were characterised by different physicochemical techniques, including elemental and thermogravimetric analysis; UV-Vis, IR, 1H-NMR, and 13C-NMR spectroscopy; molar conductance measurements; and mass spectrometry. The crystal structure of the H2L1 ligand was determined by single crystal X-ray diffraction studies. The spectral data showed that the thiosemicarbazone behaves as an NNS tridentate ligand through the nitrogen atoms of the azomethine group and pyrazine ring and the sulphur atom of the thioamide group. Elemental and thermal analyses indicated that the obtained metal complexes had a 1 : 1 stoichiometry (metal-ligand). The interactions between these complexes and calf thymus DNA (CT-DNA) were studied by electronic absorption and viscosity measurements. The activities of these compounds against oxidative DNA cleavage were examined by agarose gel electrophoresis. Cu(II) and Ni(II) complexes can wind DNA strands through groove interactions and promote strand breakage of the plasmid pmCherry under oxidative stress conditions. Moreover, all the complexes could interact more strongly with DNA than could with the free ligands. Finally, the antibacterial activities of the ligands and their complexes were determined by in vitro tests against Gram-positive bacterial strains (S. aureus ATCC 25923, L. monocytogenes ATCC 19115, and B. cereus ATCC 10876) and Gram-negative bacterial strains (E. coli ATCC 25922, S. typhimurium ATCC 14028, and K. pneumoniae ATCC BAA-2146) using the broth microdilution method. The metal complexes showed greater antimicrobial activities than the precursor ligands against some of the microorganisms.


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