Synthesis, spectral characterization, redox and antimicrobial activity of Schiff base transition metal(II) complexes derived from 4-aminoantipyrine and 3-salicylideneacetylacetone

Abstract

A novel tetradentate N 2 O 2 type Schiff base, synthesized from 1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one(4-aminoantipyrine) and 3-salicylidene-acetylacetone, forms stable complexes with transition metal ions such as Cu II , Ni II , Co II and Zn II in ethanol. Microanalytical data, magnetic susceptibility, IR, UV-Vis., 1 H-NMR, ESR and Mass spectral techniques were used to confirm the structures. Electronic absorption spectra of the complexes suggest a square-planar geometry around the central metal ion. These complexes show higher conductance values, supporting their electrolytic nature. The monomeric nature of the complexes was confirmed from their magnetic susceptibility values. Cyclic voltammogram of the copper(II) and nickel(II) complexes in DMSO solution at 300 K were recorded and the results are discussed. The X-band ESR spectra of the copper complex were recorded and the molecular orbital coefficient values were calculated from the spectra. The in vitro antimicrobial activities of the investigated compounds were tested against bacteria such as Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis and Escherichia coli and fungi like Aspergillus niger and Rhizoctonia bataicola. Most of the metal chelates show higher antimicrobial activity for the above microorganisms than that of the free ligand.

Expression of Concern: One‐Step Synthesis of Biaryls under Mild Conditions

“…The FTIR, [44] UV/Vis, and 1 H NMR spectroscopy, [45] mass spectrometry, and elemental analysis results confirm the tetrahedral geometry of the synthesized complex. The FTIR, [44] UV/Vis, and 1 H NMR spectroscopy, [45] mass spectrometry, and elemental analysis results confirm the tetrahedral geometry of the synthesized complex.…”

Copper(II) Complexes with Ligands Derived from 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one: Synthesis and Biological Activity

“…The antimicrobial activity of the Schiff bases of antipyrine and their complexes have been discussed previously [9][10][11][12][13][14][15][16].…”

Electron Spin Resonance Spectral Characterization and DNA Binding Studies of Metal Complexes with Heterocyclic Ligands Derived from 4 -Aminoantipyrine and 5-Chlorosalicylaldehyde / 3-Ethoxysalicylaldehyde

“…There have been many reports concerning the applications of ESR to square -planar or distorted octahedral complexes of Cu(II) and of the interpretations of the ESR parameters in terms of covalency of the metal-ligand bonding 9 . The Cu(II) complexes exhibited well resolved anisotropic signals in the parallel and perpendicular regions as shown in Figures 1 and 2.…”