scholarly journals Polydentate Schiff Base Ligands and Their La(III) Complexes: Synthesis, Characterization, Antibacterial, Thermal, and Electrochemical Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Ali E. Şabik ◽  
Muharrem Karabörk ◽  
Gökhan Ceyhan ◽  
Mehmet Tümer ◽  
Metin Dığrak

We synthesized the Schiff base ligands H2L1–H2L4 and their La(III) complexes and characterized them by the analytical and spectroscopic methods. We investigated their electrochemical and antimicrobial activity properties. The electrochemical properties of the ligands H2L1–H2L4 and their La(III) complexes were studied at the different scan rates (100 and 200 mV), different pH ranges (), and in the different solvents. The electrooxidation of the Schiff base ligands involves a reversible transfer of two electrons and two protons in solutions of pH up to 5.5, in agreement with the one-step two-electron mechanism. In solutions of pH higher than 5.5, the process of electrooxidation reaction of the Schiff base ligands and their La(III) complexes follows an ECi mechanism. The antimicrobial activities of the ligands and their complexes were studied. The thermal properties of the metal complexes were studied under nitrogen atmosphere in the range of temperature 20–1000°C.

2012 ◽  
Vol 455-456 ◽  
pp. 740-745
Author(s):  
W. Zhong ◽  
Guo Qing Zhong ◽  
Y. Zhang ◽  
Q. Zhong

Three zinc (II) complexes of the amino acid Schiff base were synthesized by the one step reaction of amino acid with aldehyde, zinc acetate in solvent-free. The compositions and structures of the complexes were characterized by elemental analyses, FTIR, XRD, TG-DSC. The compositions of the complexes are ZnL•nH2O (L = sal-leu, sal-ala, van-leu; sal = salicylaldehyde; van = vanillic aldehyde; leu = leucine; ala = alanine). Infrared spectra of the complexes indicate that the Schiff base ligands are formed, zinc ion is coordinated to the Schiff base ligands as terdentate with O, O and N donors from carboxylic, phenolic and imino groups respectively, the coordination numbers of zinc ion is four. The possible pyrolysis reactions in the thermal decomposition process of the complexes, the experimental and calculated percentage mass loss are also given.


RSC Advances ◽  
2015 ◽  
Vol 5 (115) ◽  
pp. 95104-95117 ◽  
Author(s):  
S. Yousef Ebrahimipour ◽  
Iran Sheikhshoaie ◽  
Jesús Castro ◽  
Michal Dušek ◽  
Zeinab Tohidiyan ◽  
...  

Two new uranyl(vi) Schiff base complexes were synthesized and characterized by physicochemical and spectroscopic methods. The antimicrobial activities of these complexes were also investigated against microorganisms.


2021 ◽  
Vol 68 (4) ◽  
pp. 1008-1015
Author(s):  
Yong Yuan ◽  
Xi-Kun Lu ◽  
Gao-Qi Zhou ◽  
Xiao-Yang Qiu

Three new copper(II) complexes, [Cu(LH)2]Br2 (1), [Cu(LH)2]NCS2 (2), and [Cu(LH)2](NO3)2 (3), where LH is the zwitterionic form of 2-bromo-6-((2-(isopropylamino)ethylimino)methyl)phenol (HL), were synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy. The structures of the complexes were further confirmed by single crystal X-ray structure determination. All compounds are mononuclear copper(II) complexes. The Cu atoms in the complexes are coordinated by two imino N and two phenolate O atoms from two LH ligands, forming square planar coordination. The compounds were assayed for their antimicrobial activities.


2018 ◽  
Vol 11 (1) ◽  
pp. 32-36
Author(s):  
I.T. Siraj ◽  
M Sule

Complexes of Mn(II), Fe(II) and Co(II) containing N, N’-bis[o-anisaldehyde]p-phenylenediamine tetradentate Schiff base as primary ligand and glycine as secondary bidentate ligand have been synthesized by reflux in 1:1:1 mole ratio and characterized both analytically and spectroscopically. Molar conductance measurement (69.02 to 86.30Ω–1 cm2 mol–1) of the complexes indicated they are weak electrolyte and magnetic susceptibility measurement shows values in range of 4.53 to 5.59BM indicating their paramagnetism. The infrared data suggested that the Schiff base coordinated via the two nitrogen atoms of the azomethine groups (1628 to 1680 cm-1) and the oxygen atoms of the adjacent methoxy groups (1341 to 1389 cm-1), while glycine coordinated via the nitrogen atom of the amino group (3060-3324 cm-1) and the oxygen atom of the carboxylate anion. Based on the analytical and spectroscopic data the complexes may be assigned an octahedral geometries and molecular formulae of the form [M(L)Gly], where M = Mn, Fe and Co, L=Schiff base and Gly = glycine. The Schiff base and its mixed ligand complexes were screened for antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhi, Mucor inducus and Aspergillus fumigatus. The complexes exhibited enhanced antimicrobial activity (10mm to 18mm) at 60 µg/disc as compared to 10mm activity of the uncoordinated Schiff base at the same concentration.Keywords: Mixed ligand complex; Schiff base, Glycine, p-phenylenediamine, o-anisaldehyde


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