Antibacterial Co(II), Cu(II), Ni(II) and Zn(II) Complexes of Thiadiazole Derived Furanyl, Thiophenyl and Pyrrolyl Schiff Bases (original) (raw)
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2015
Co(II), Ni(II), Cu(II) and Cd(II) complexes of bidentate Schiff bases derived from the condensation of 4-amino-5-benzyl4H-1,2,4-triazoles-3-thione with pyridine-2-carboxyaldehyde, pyridine-3-carboxya- ldehyde and pyridine-4carboxyaldehyde were synthesized. The Schiff bases and their metal complexes were characterized by elemental and thermogravimetric analyses, spectral measurements (FT-IR, UV-Vis), molar conductance and magnetic moment measurements. Square planar (Cu(II) complexes), tetrahedral (Cd(II) complexes) and octahedral (Co(II) and Ni(II) complexes) geometries have been proposed. The presence of coordinated water in the metal complexes is confirmed by thermal analysis and IR data. The Schiff bases act as bidentate ligands coordinating via the azomethine nitrogen and thiolate sulfur atoms. The Schiff bases and their metal complexes have been screened for antimicrobial activity against six bacteria, namely Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Microc...
2023
Schiff bases are the condensation products of primary amines with aldehydes or ketones in which the carbonyl group is replaced by imine or azomethine. They are valuable class of organic compounds and able to coordinate a number of different metal ions, hence stabilizing them in a variety of oxidation states. The chemistry of transition metal complexes with Schiff bases is quite rich in terms of applicability. The importance of polydentate Schiff bases cannot be ignored because they can easily be attached to a metal ion due to the formation of highly stable chelates, which are necessary for their action under certain tough conditions. The chemistry of Schiff's bases has attracted chemists for having active role in biological field and a wide range of biological applications such as antiviral, anticancer, antibacterial, antifungal, antioxidant, analgesic and antiglycation properties. Moreover, a variety of Schiff bases can inhibit the enzymatic actions due to their structural compatibility to biological systems. The compound containing thiazole moiety show excellent biological activities. Thiazide derivatives of natural or synthetic origin have been applied as antibacterial, antifungal, anticancer and antiviral agents. Keeping in view the above mentioned applications, in the current study Schiff bases 1 and its complex 2 was synthesize and structurally characterize by commonly used spectroscopic technique (NMR). The antibacterial activity of the synthesized compounds has been determined.
Modern Chemistry, 2014
The Schiff bases, formed by condensation of 2-thiophenecarboxaldehyde with 2-aminothiophenol (LH) and propane-1,2-diamine (L 1), and their complexes of Ni(II), Cu(II), Zn(II) and Cd(II) have been prepared and characterized by elemental analysis, and magnetic and spectroscopic measurements. Infrared and NMR spectra of the complexes agree with the coordination to the central metal atom through the nitrogen of the azomethine (-HC=N-) group and the sulfur atom of the thiophene ring. Magnetic susceptibility data coupled with electronic suggest octahedral structure for the complexes. Conductance measurements suggest the non-electrolytic nature of the complexes. Stoichiometry of complexes has been suggested as [M(L) 2 ] and [ML 1 Cl 2 ]. The Schiff base and its metal chelates have been screened for their in vitro antibacterial activity against four human pathogenic bacteria. Ligands show moderately whereas some of metal chelates show highly antibacterial activity against them.
Communication in Physical Sciences, 7(2) 115-125, 2021
A novel Schiff base and its Ni(II) complex have synthesized from benzaldehyde and sulphathiazole. The synthesized products were characterized using elemental analyser, ultra violet visible, Fourier transformed infra red, proton and carbon-13 spectrophotometers. Results obtained from infra red spectrum suggested that the ligand is coordinated to nickel ions through two azomethine nitrogen, and one amine nitrogen. Electronic spectral measurement indicated that there is a ligand to metal charge transfer and from the continuous variation method, metal: ligand ratio of 1:1 was proposed. Elemental analysis and spectroscopic studies suggested that the Schiff base behaved as a tridentate ligand towards nickel ion. I n v i t r o a ntibacterial sensitivity tests of the ligand and its Ni (II) complex against Staphylococcus aureus, Echerichia coli, Pseudomonas aeruginosa and Salmonella typhi showed that they exhibited strong activities. However, the Ni(II) complex was observed to be more potent than the Schiff base..
Revue Roumaine de Chimie, 2020
In an effort to study the effect of 1,3,4-thidiazole based molecules on bacteria, fungal and tuberculosis species, we synthesized a series of Schiff bases (2a-2m) by reacting a variety of carbonyl compounds with 5-amino-1,3,4- thiadiazole-2-thiol. Molecular structure of these compounds was retrieved by spectral methods and elemental analysis. All these compounds were evaluated for their antibacterial, antifungal and antitubercular activities employing standard biological protocols. The compounds 2m and 2l substituted with the electron withdrawing fluorine and nitro groups showed excellent inhibitory activity against Staphylococcus aureus, Aspergillus niger and Candida tropicalis with an MIC of 8 µg/mL whereas 2i containing the electron releasing dimethylamino group showed potent activity against Proteus vulgaris. Additionally, 2m along with 2j, 2k and 2l also exhibited superior antimycobacterial activity than the standard pyrazinamide. The activity data for these compounds pave the ...
Jordan Journal of Chemistry
Some new Schiff base metal complexes of Cr(III), Co(II), Ni(II) and Cu(II) derived from N-(4-chlorobenzylidene)-5-methyl-1,3-thiazol-2-amine (CBAM) and N-[4-(dimethylamino)benzylidene]-6-nitro-1,3-benzothiazol-2-amine (DBAT) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR, magnetic susceptibility, thermal, electrical conductivity and XRD analysis. The complexes exhibit coordination number 4 or 6. The Schiff base and metal complexes show a good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.
Transition Metal Chemistry, 2010
Six Cu(II) complexes of Schiff base ligands of arylidene-2-(4-(4-bromo/methoxy-phenyl)thiazol-2-yl) hydrazines have been synthesized, characterized and screened for DNA cleavage and antimicrobial activities. The chemical structures of the complexes were deduced by physicochemical and spectroscopic methods. Elemental analyses indicated that the stoichiometry of the complexes is CuL2 (L = Schiff base ligand). The DNA cleavage activities of the complexes were evaluated by agarose gel electrophoresis in the presence and absence of oxidant (H2O2) and free radical scavenger (DMSO). All the six complexes showed significant nuclease activity in the presence of H2O2, and two of the complexes showed moderate nuclease activity even in the absence of oxidant. The complexes did not show nuclease activity in the presence of free radical scavenger. The compounds were tested for activity against selected bacteria and fungi.
Polyhedron, 2015
In order to search for new bioactive molecules with significant antimicrobial action, a series of 1,2,4-triazole and naphthalene analogs bearing structurally diverse substituents, N-(3-mercapto-5-(naphthalen-1-yl)-4H-1,2,4triazol-4-yl)(aryl)amides 3a-l were synthesized in good yield by a multi-step synthetic procedure. Their antimicrobial activity was screened against various Gram-positive and Gram-negative bacteria and fungi. Compounds 3a, 3f, 3g, 3j, and 3k exerted strong inhibition of the investigated bacterial and fungal strains compared to control antibiotic ampicillin and antifungal griseofulvin. On the basis of statistical analysis, it is observed that the compounds give significant co-relation. All the synthesized compounds have been characterized by IR, 1 H NMR, 13 C NMR, and mass spectral data.
Journal of Molecular Structure, 2021
A series of pyridines, pyrimidinones, oxazinones and their derivatives were synthesized as antimicrobial agents using citrazinic acid (2,6-dihydroxyisonicotinic acid) as a starting material. α,β-Unsaturated ketones 3a-c were condensed with cyanothioacetamide in the presence of ammonium acetate to give 2-cyanopyridinethiones 4a-c, which were reacted with ethyl chloroacetate to yield the corresponding cyano esters 5a-c. The esters 5a-c were cyclized by action of sodium methoxide to aminoesters 6a-c, which were aminolyzed with ammonia to corresponding aminoamide derivatives 7a-c. Also, the esters 6a-c were hydrolyzed with NaOH to the corresponding sodium salt 8a-c, which were treated with acetic anhydride to afford 2-methyloxazinones 9a-c. The latter compounds were treated with ammonium acetate to afford 2-methylpyrimidinones 10a-c, followed by methylation with methyl iodide to yield 2,3-dimethyl-pyrimidinones 11a-c. The antimicrobial screening showed that many of these compounds have good antibacterial and antifungal activities comparable to streptomycin and fusidic acid used as reference drugs.