scholarly journals Water Soluble Mixed Ligand Complexes Spectral, antioxidant, antimicrobial and DNA interaction studies

2018 ◽  
Vol 69 (11) ◽  
pp. 3169-3177 ◽  
Author(s):  
Karunganathan Sakthikumar ◽  
Murugesan Sankarganesh ◽  
Jeyaraj Dhaveethu Raja ◽  
Liviu Mitu

A new series of water soluble mixed ligand complexes [MII(L)(bpy)AcO].nH2O M = Cu, (n=1) (1); Co (2), Mn (3), Ni (4) (n=4) and Zn (5) (n=2) have been synthesized from 2-(2-Morpholinoethylimino)methyl)phenol Schiff base ligand (HL) and 2,2�-bipyridine in a 1:1:1 molar ratio. The resulting complexes were characterized by spectral techniques. The spectral data of these complexes suggest an octahedral geometry. In vitro antioxidant activity results of DPPH assay, hydroxyl radical, super oxide and nitric oxide for complexes (1-5) were compared with ligand (HL) and in vitro antimicrobial activities of all compounds were examined against selected bacterial and fungal strains which indicate that the complexes exhibit higher antimicrobial activity than free ligand (HL). Gel electrophoresis results indicated that, complexes (1) and (2) have exhibited more DNA cleavage efficiency than others. The intrinsic binding constant (Kb) values for the complexes (1-5) observed by electronic absorption technique were in the order of (1) ] (4) ] (5) ] (2) ] (3) and DNA binding affinity values for these complexes obtained by viscosity measurements were in the order of ethidium bromide ] (1) ] (2) ] (3) ] (4) ] (5).

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.


2011 ◽  
Vol 8 (3) ◽  
pp. 1258-1263 ◽  
Author(s):  
A. K. Mapari ◽  
M. S. Hate ◽  
K. V. Mangaonkar

The mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with Schiff basesN-(2-hydroxy-1-naphthylidene)-4-methylaniline (L1H) andN-(2-hydroxybenzylidene)-2,3-dimethylaniline (L2H) have been synthesized and characterized. The resulting complexes were characterized by elemental analysis, thermogravimetric analysis, magnetic moment measurements, conductivity measurements,1H NMR, IR, UV-visible and ESR spectral studies. The Schiff bases acts as bidentate monobasic ligands, coordinating through deprotonated phenolic oxygen and azomethine nitrogen atoms. The complexes are non-electrolytic in DMSO. The presence of the two coordinated water molecules in these complexes was indicated by IR spectra and thermogravimetric analysis of the complexes. From the analytical and spectral data the stoichiometry of these complexes have been found to be [M(L1)(L2)(H2O)2] {where M = Co(II) , Ni(II), Cu(II) and Zn(II)}. It is found that Co(II), Ni(II), Cu(II) and Zn(II) complexes exhibited octahedral geometry. The antimicrobial activities of ligands and their mixed ligand complexes were screened by disc diffusion method. It is found that the metal complexes have higher antimicrobial activity than the free ligand.


2011 ◽  
Vol 40 (37) ◽  
pp. 9404 ◽  
Author(s):  
Roman Buchtík ◽  
Zdeněk Trávníček ◽  
Ján Vančo ◽  
Radovan Herchel ◽  
Zdeněk Dvořák

2011 ◽  
Vol 46 (9) ◽  
pp. 4537-4547 ◽  
Author(s):  
Verasuntharam M. Manikandamathavan ◽  
Royapuram P. Parameswari ◽  
Thomas Weyhermüller ◽  
Hannah R. Vasanthi ◽  
Balachandran Unni Nair

2021 ◽  
Vol 9 (09) ◽  
pp. 900-909
Author(s):  
Anupama Srivastava ◽  
◽  
Shilpi Srivastava ◽  
Om. P. Pandey ◽  
Soumitra K. Sengupta ◽  
...  

Titanium(IV) complexes of type[(η5-C5H5)2TiCl(L)] have been synthesized by the reactions of bis(cyclopentadienyl)titanium(IV)dichloride with Schiff bases (LH) derived by the condensation of 5-(substituted aryl)-2-hydrazino-1,3,4-oxadiazole and indoline-2,3-dione in tetrahydrofuranin the presence oftriethylamine. All these complexes are soluble in PhNO2, DMF and DMSO.The complexes were characterized by elemental analyses, electrical conductance, magnetic susceptibility, UV-Vis, IR, 1H NMR, 13C NMR, XRD and SEM spectral techniques. Low molar conductance values indicate that they are non-electrolytes. The spectral data indicate5-coordinate geometry for the complexes.XRD pattern indicate that the complexes have monoclinic crystal system and particle sizes were found 49.36 nm (nano-size). In vitro antifungal activity of synthesized compounds was evaluated against fungi Aspergillusniger, Aspergillusflavus,ColletotrichumfalcatumandIn vitro antibacterial activity was determined by screening the compounds against gram negative (P. aeruginosa, S.typhi) and gram positive (S. aureus and B.subtilis) bacterial strains using minimum inhibition concentration method (MIC) by serial dilution technique. The titanocene(IV) complexes have higher antimicrobial effect than the parent Schiff bases.


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.


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