Combined experimental and theoretical rationalization on zinc(II) mediated unusual conversion of 18-membered Schiff-base macrocycle to 18-membered imine-amine macrocycle having imidazolidine side rings: investigation of their bio-relevant catalytic activities

2021 ◽  
Author(s):  
Tonmoy Chakraborty ◽  
Somali Mukherjee ◽  
Rumana Parveen ◽  
Arpita Chandra ◽  
Debabrata Samanta ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Condensation Reaction ◽  
Catalytic Activities

The 2:2 condensation reaction of 2,6-diformyl-4-isopropyl phenol and N'-(2-aminoethyl)ethane-1,2-diamine leads to a macrocycle Schiff base ligand (H2L) with N6O2 chromophore, which in presence of ZnX2 transformed into a new [2+2]...

scholarly journals Synthesis and Spectral Studies of 4,4′-(Hydrazine-1,2-diylidenedimethylylidene)-bis-(2- methoxyphenol) and Its Transition Metal Complexes with Promising Biological Activities

2020 ◽  
Vol 32 (7) ◽  
pp. 1768-1772
Author(s):  
Anita Rani ◽  
Manoj Kumar ◽  
Hardeep Singh Tuli ◽  
Zahoor Abbas ◽  
Vinit Prakash
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Schiff Base Ligand ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Analytical Techniques ◽  
Spectral Studies

The study describes the synthesis, characterization and biological activity of a novel Schiff base ligand and its transition metal complexes. The Schiff base ligand was obtained by a condensation reaction between 4-hydroxy-3-methoxybenzaldehyde (p-vanillin) and hydrazine hydrate using ethanol as solvent. A new series of Ni(II) and Fe(III) complexes were also derived by reaction of prepared Schiff base ligand with NiCl2 and FeCl3. Both the ligand and its metal complexes were characterized by solubility, melting point and elemental analysis. These compounds were further identified by analytical techniques, FTIR, NMR and mass spectrometry. The ligand and its transition metal complexes were also subjected to in vitro biological activities i.e. antimicrobial, antiangiogenic and DNA photo cleavage. For antimicrobial activity compounds were tested against two strains of bacteria and two strains of fungi. Different concentrations of prepared compounds were treated with fertilized chicken eggs and plasmid DNA to find out antiangiogenic and DNA photocleavage activity, respectively.

scholarly journals Synthesis, Characterization and Antibacterial Activity of Schiff Base, 4-Chloro-2-{(E)-[(4-Fluorophenyl)imino]methyl}phenol Metal (II) Complexes

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
F. K. Ommenya ◽  
E. A. Nyawade ◽  
D. M. Andala ◽  
J. Kinyua
Keyword(s):  
Antibacterial Activity ◽  
Schiff Base ◽  
Metal Complexes ◽  
Elemental Analysis ◽  
Schiff Base Ligand ◽  
Condensation Reaction ◽  
Molar Conductance ◽  
Diffusion Method ◽  
Elemental Analysis Data ◽  
Ft Ir

A new series of Mn (II), Co (II), Ni (II), Cu (II), and Zn (II) complexes of the Schiff base ligand, 4-chloro-2-{(E)-[(4-fluorophenyl)imino]methyl}phenol (C13H9ClFNO), was synthesized in a methanolic medium. The Schiff base was derived from the condensation reaction of 5-chlorosalicylaldehyde and 4-fluoroaniline at room temperature. Elemental analysis, FT-IR, UV-Vis, and NMR spectral data, molar conductance measurements, and melting points were used to characterize the Schiff base and the metal complexes. From the elemental analysis data, the metal complexes formed had the general formulae [M(L)2(H2O)2], where L = Schiff base ligand (C13H9ClFNO) and M = Mn, Co, Ni, Cu, and Zn. On the basis of FT-IR, electronic spectra, and NMR data, “O” and “N” donor atoms of the Schiff base ligand participated in coordination with the metal (II) ions, and thus, a six coordinated octahedral geometry for all these complexes was proposed. Molar conductance studies on the complexes indicated they were nonelectrolytic in nature. The Schiff base ligand and its metal (II) complexes were tested in vitro to evaluate their bactericidal activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus typhi) using the disc diffusion method. The antibacterial evaluation results revealed that the metal (II) complexes exhibited higher antibacterial activity than the free Schiff base ligand.

scholarly journals Metal Complexes of Macrocyclic Schiff-Base Ligand: Preparation, Characterisation, and Biological Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Riyadh M. Ahmed ◽  
Enaam I. Yousif ◽  
Hasan A. Hasan ◽  
Mohamad J. Al-Jeboori
Keyword(s):  
Biological Activity ◽  
Schiff Base ◽  
Metal Complexes ◽  
Schiff Base Ligand ◽  
Condensation Reaction ◽  
Free Ligand ◽  
Inhibition Zone ◽  
Square Planar ◽  
Planar Geometries ◽  
Macrocyclic Schiff Base

A new macrocyclic multidentate Schiff-base ligand Na4L consisting of two submacrocyclic units (10,21-bis-iminomethyl-3,6,14,17-tricyclo[17.3.1.18,12]tetracosa-1(23),2,6,8,10,12(24),13,17,19,21,-decaene-23,24-disodium) and its tetranuclear metal complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) are reported. Na4L was prepared via a template approach, which is based on the condensation reaction of sodium 2,4,6-triformyl phenolate with ethylenediamine in mole ratios of 2 : 3. The tetranuclear macrocyclic-based complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The mode of bonding and overall geometry of the compounds were determined through physicochemical and spectroscopic methods. These studies revealed tetrahedral geometries about Mn, Co, and Zn atoms. However, square planar geometries have been suggested for NiIIand CuIIcomplexes. Biological activity of the ligand and its metal complexes against Gram positive bacterial strainStaphylococcus aureusand Gram negative bacteriaEscherichia colirevealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand. However, these metal complexes do not exhibit any effects on the activity ofPseudomonas aeruginosabacteria. There is therefore no inhibition zone.

scholarly journals Synthesis, Characterization and Biological Evaluation of New Schiff Base Ligand derived from 3-hydroxy-benzaldehyde and p-toluidine and its Divalent Metal Ions

2020 ◽  
Vol 71 (4) ◽  
pp. 47-58
Author(s):  
Noreen Mazhar ◽  
Mehwish Aftab ◽  
Tariq Mahmud ◽  
Muhammadasim Raza Basra ◽  
Mansoor Akhtar ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Schiff Base ◽  
Metal Complexes ◽  
Schiff Base Ligand ◽  
Protein Denaturation ◽  
Condensation Reaction ◽  
Free Ligand ◽  
Biological Evaluation ◽  
Divalent Metal ◽  
Anti Inflammatory

A new Schiff base ligand (L) and its transition divalent metal complexes were prepared by the condensation reaction; Reaction was carried out at 70-80 oC by refluxing equimolar ratio of toluidine and aldehyde by continuous stirring for 5-6 hours. Synthesized ligand and Ni(II), Fe(II), Co(II), Mn(II) and Zn(II) bimetallic complexes were characterized by using FT-IR, UV-visible spectroscopy, AAS, Single crystal X-ray analysis, 1H-NMR, molar conductance. Compounds were screened against two fungus Candida glabrata and Candida albicans by agar tube dilution protocol. In vivo anti-inflammatory activity via induced paw edema method and in vitro results by heat induced protein denaturation method were checked. Synthesized compounds were also showed antioxidant activity by using DPPH (diphenylpicrylhydrazyl) and Trolox was used as standard. These studies show that ligand and almost all metal complexes are reactive towards biological assays against reported standard drugs. Zn-L indicates more activeness for antioxidant activity and free ligand while Co-L recognized as more effective anti-inflammatory drug.

Synthesis, structure and catalytic activities of nickel(II) complexes bearing N4 tetradentate Schiff base ligand

2018 ◽  
Vol 1160 ◽  
pp. 9-19 ◽  
Author(s):  
Saikat Sarkar ◽  
Sanat Kumar Nag ◽  
Asoke Prasun Chattopadhyay ◽  
Kamalendu Dey ◽  
Sk. Manirul Islam ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Catalytic Activities ◽  
Tetradentate Schiff Base

scholarly journals Synthesis, Characterization and Biological Evaluation of Schiff Base (N-4-(thiophene-2-yl-methyleneamino)-2,6-dimethylpyrimidine-4-yl)benzenesulfonamide and its Complexes with Cu(II), Ni(II), Co(II), Fe(II), Mn(II), Zn(II) Ions

2020 ◽  
Vol 71 (1) ◽  
pp. 206-212 ◽  
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver ◽  
Gabriel Bratu ◽  
...  
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Schiff Base Ligand ◽  
Condensation Reaction ◽  
Klebsiella Oxytoca ◽  
Biological Evaluation ◽  
Anti Inflammatory

Two step synthesis of Schiff base ligand and its transition metal complexes was done by condensation reaction. In first step, the drug and aldehyde in equimolar ratio were refluxed for one hour at pH 8-9 in order to get Schiff base ligand. In second step, ligand and metal salts were refluxed for 2 hour. The ligand and Cu(II), Ni(II), Co(II), Fe(II), Mn(II), Zn(II) complexes were characterized by using different instruments like FT-IR, 1H-NMR, 13C-NMR, Mass, Atomic absorption spectrometer, Elemental analyzer, UV-visible spectrophotometer, Evans balance, Conductivitymeter and Thermogravimeter. In vitro antibacterial, antifungal and anti-inflammatory activities were also studied. The synthesized ligand and transition metal complexes were tested against Escherichia coli, Enterobacter aerogenes, Staphylococcus aureus, Bacillus pumilus, Klebsiella oxytoca, Clostridium butyrium, Mucor and Aspergillus niger. These studies demonstrated the enhanced activity of metal complexes against reported bacterial and fungal strains when compared with free Schiff base ligand. The Cu(II) complex recognized as anti-inflammatory agent while the parent drug showed no activity.

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