scholarly journals Synthesis, Spectroscopic Characterization and Biological Studies of Mn(II), Cu(II), Ni(II), Co(II) and Zn(II) Complexes with New Schiff Base of 2-((Pyrazine-2-ylimino)methyl)phenol

2021 ◽  
Vol 11 (19) ◽  
pp. 9067
Author(s):  
Hanan B. Howsaui ◽  
Abeer A. Sharfalddin ◽  
Magda H. Abdellattif ◽  
Amal S. Basaleh ◽  
Mostafa A. Hussien

In the search for novel anticancer complex, transition metal complexes of Schiff base derived from 2-aminopyrazine and salicylaldehyde were successfully synthesized and characterized based on elemental analyses, spectroscopic and thermal analysis. The IR spectra showed the ligand is a tridentate chelator with O, N and N atoms. donor sites in the Zn(II), Co(II), Ni(II), and Mn(II) complexes. Contrary, it behaved a bidentate chelator in the Cu complex by O and N. Molar ratio data revealed that the ligand to metal ratio was 1:2 for Co(II) Cu(II) and Zn(II) while it was 1:1 for Mn(II) and Ni(II) complexes. The obtained complexes have the formulae [M(L)2] (where M = Co(II) and Zn(II), [M(L)Cl(2H2O)]·H2O (where M = Ni(II) and Mn(II) were octahedral geometry). The computational studies were performed by DFT calculations to compare the optimized geometries with the experimental values. The interaction of these complexes with calf thymus DNA (CT-DNA) was investigated by UV-Vis spectroscopic technique. Molecular docking studies were against three protein cancer to investigate the binding ability of the new compounds. The anticancer activity was studied with different cell lines and the IC50 of the Cu(II) complex for (HOP-62) showed a practical result. The LD50 values of Zn(II) and Co(II) complexes showed that they are non-toxic at doses up to 370 mg/kg.

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
M. M. El-ajaily ◽  
H. A. Abdullah ◽  
Ahmed Al-janga ◽  
E. E. Saad ◽  
A. A. Maihub

La(III), Zr(IV), and Ce(IV) chelates of 2-[(4-[(Z)-1-(2-hydroxyphenyl)ethylidene]aminobutyl)-ethanimidoyl]phenol were synthesized and characterized by using several physical techniques. The Schiff base was obtained by refluxing of o-hydroxyacetophenone with 1,4-butanediamine in 2 : 1 molar ratio. The CHN elemental analysis results showed the formation of the Schiff base and the chelates has been found to be in 1 : 1 [M : L] ratio. The molar conductance measurements revealed that all the chelates are nonelectrolytes. Structural elucidations of the ligand and its chelates were based on compatible analytical and spectroscopic evidences. The infrared spectral data revealed that the Schiff base coordinates to the metal ions through active sites which are –OH and –C=N groups. According to the electronic spectral data, an octahedral geometry was proposed for the chelates. The synthesized ligand and its metal chelates were screened for their antimicrobial activity against two Gram negative (Escherichia coli, Salmonella kentucky) and two Gram positive (Lactobacillus fermentum, Streptococcus faecalis) bacterial strains, unicellular fungi (Fusarium solani), and filamentous fungi (Aspergillus niger). The activity data showed that the metal chelates have antibacterial and antifungal activity more than the parent Schiff base ligand against one or more bacterial or fungi species. The results also indicated that the metal chelates are higher sensitive antimicrobial agents as compared to the Schiff base ligand.


2019 ◽  
Vol 41 (6) ◽  
pp. 1055-1055
Author(s):  
Ahmed Hassan Abdel Salam Ahmed Hassan Abdel Salam

Various six coordinated copper(II) complexes of novel (E)-4-hydroxy-6-methyl-3-(1-(p-tolylimino) ethyl-2H-pyran-2-one (HL1) and (E)-3-(1-(4-chlorophenylimino) ethyl-4-hydroxy-6-methyl-2H-pyran-2-one (HL2) derived from 3-Acetyl-2-hydroxy-6-methyl-4H-pyran-4-one (dehydroacetic acid, DHA) and aniline derivatives (p-chloroaniline and p-toluidine) were fabricated. The coordination mode of Schiff base donor atoms with copper ions was well investigated by thermal and elemental analyses, FTIR, UV-vis, 1H, 13C-NMR spectral tools and measurements of magnetic susceptibility as well as molar conductance at ambient temperature. The novel neutral bidentate Schiff base ligands (HL1 and HL2) linked to Cu(II) cation via the azomethine-N and hydroxyl-O atoms and to acetate and nitrate anions in bidentate bridging mode to form polymeric octahedral complexes. The thermal study showed the stepwise removal of water of hydration and anions and decomposition of these chelates. The decomposition products were examined and the relative thermal stabilities of these chelates were evaluated. Different parameters of activation were derived from the thermal curves by Coats–Redfern methodology. The degradation steps of the metal complexes had positive free energy values indicating their non-spontaneous nature. The antifungal and antibacterial activities of all investigated compounds were also studied. The magnetic susceptibility measurements and conductance data were investigated and provided evidence for the non-electrolytic character of the complexes.


2020 ◽  
Vol 45 (1) ◽  
pp. 18
Author(s):  
Abidemi Iyewumi Demehin ◽  
Mary Adelaide Oladipo ◽  
Banjo Semire

Ni(II) mixed-ligand complexes of [NiLNH3] (where L= N-salicylidene-o-aminophenol (L1), N-(5-methoxysalicylidene-o-aminophenol) (L2) and N-(2-hydroxy-1-naphthalidene)-o-aminophenol) (L3) containing ONO tridentate Schiff bases and ammonia were synthesized and characterized by elemental analysis, infrared, ultraviolet-visible, proton and carbon-13 spectroscopies. Theoretical calculations were also performed on the optimized structures of the Ni(II) mixed-ligand complexes. The Infrared and ultraviolet-visible spectra of the complexes were calculated, and the results compared with the corresponding experimental spectra to augment the experimental structural identification. The elemental analysis data confirmed the formation of 1:1:1 [metal: Schiff base: ammonia] molar ratio. The NMR spectra showed that the Schiff bases coordinated to the Ni(II) ion via the two deprotonated phenolic oxygen and azomethine nitrogen atoms. The biological studies showed that the complexes exhibited higher antibacterial and antioxidant activities than the free Schiff base ligands.


2015 ◽  
Vol 71 (7) ◽  
pp. 578-583 ◽  
Author(s):  
William Clegg ◽  
Ross W. Harrington ◽  
Kazem Barati ◽  
Mohammad Hossein Habibi ◽  
Morteza Montazerozohori ◽  
...  

Reaction of copper(I) thiocyanate and triphenylphosphane with the bidentate Schiff baseN,N′-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, (1); systematic name (1E,1′E,2E,2′E)-N,N′-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]}, C20H18N4O4, in a 1:1:1 molar ratio in acetonitrile resulted in the formation of the complex {(1E,1′E,2E,2′E)-N,N′-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ2N,N′}(thiocyanato-κN)(triphenylphosphane-κP)copper(I)], [Cu(NCS)(C20H18N4O4)(C18H15P)] or [Cu(NCS)(Nca2en)(PPh3)], (2). The Schiff base and copper(I) complex have been characterized by elemental analyses, IR, electronic and1H NMR spectroscopy, and X-ray crystallography [from synchrotron data for (1)]. The molecule of (1) lies on a crystallographic inversion centre, with atransconformation for the ethylenediamine unit, and displays significant twists from coplanarity of its nitro group, aromatic ring, conjugated chain and especially ethylenediamine segments. It acts as a bidentate ligand coordinatingviathe imine N atoms to the CuIatom in complex (2), in which the ethylenediamine unit necessarily adopts a somewhat flattenedgaucheconformation, resulting in a rather bowed shape overall for the ligand. The NCS−ligand is coordinated through its N atom. The geometry around the CuIatom is distorted tetrahedral, with a small N—Cu—N bite angle of 81.56 (12)° and an enlarged opposite angle of 117.29 (9)° for SCN—Cu—P. Comparisons are made with the analogous Schiff base having no nitro substituents and with metal complexes of both ligands.


2021 ◽  
Vol 46 (2) ◽  
Author(s):  
I. G. Osigbemhe ◽  
M. E. Khan ◽  
A. P. Oviawe ◽  
M.L Ugheoke

Manganese(II) complexes of 2-{[(2-hydroxy-5-nitrophenyl) methylidene]amino} nicotinic acid derived from o-phenylenediamine and 5- nitrosalicaldehyde were synthesized and characterized by elemental analysis, using IR, 1HNMR, 13CNMR, and GCMS. They were screened against known disease causative microbes to establish their potentials as antimicrobial agents compared with national standards drugs. Results showed that, a Schiff base exhibited antimicrobial action against all the bacteria and most of the fungi with exception of Candidas. albicans isolate, which exhibited zero diameter zone of inhibition. It was also found that the synthesized Schiff base exhibited two digits purity range, implying that it was relatively stable. The metal complex was found to be more susceptible in overall biological activity due to the structural stability, showing their potency in pharmacognocy.


2021 ◽  
Vol 5 (2) ◽  
pp. 477-488
Author(s):  
G. Osigbemhe ◽  
M. E. Khan ◽  
A. Olusegun ◽  
H. D. Kabiru

Iron (II) complexes of 2-{[(2-hydroxy-5-methoxyphenyl) methylidene]amino} nicotinic acid derived from o-phenylenediamine and 5- methoxysalicaldehyde were synthesized and characterized by elemental analysis, using  UV-Visible, IR, 1HNMR, 13CNMR,  They were screened against known disease causative microbes to establish their effectiveness and efficacies as antimicrobial agents compared with national standards drugs, ampiclox and ketoconazole. Results showed that, the Schiff base exhibits antimicrobial action against all the bacteria and most of the fungi with exception of Candidas. albicans which exhibited naught diameter zone of inhibition. It was also found that the synthesized Schiff base exhibited two digits purity range, implying that it is relatively stable.  The metal complex was found to be more susceptible in overall biological activity than the Schiff base synthesized and studied due to their structural stability in relationship to its activity. This has opened another drug window for the remedy to human diseases caused by these microbes


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