A new series of transition metal complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) have been synthesized from the Schiff base (L) derived from 4-aminoantipyrine, 3-hydroxy-4-nitrobenzaldehyde and o-phenylenediamine. Structural features were obtained from their elemental analyses, magnetic susceptibility, molar conductance, mass, IR, UV-Vis, 1H NMR and ESR spectral studies. The data show that these complexes have composition of ML type. The UV-Vis, magnetic susceptibility and ESR spectral data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The redox behaviour of copper and vanadyl complexes was studied by cyclic voltammetry. Antimicrobial screening tests gave good results in the presence of metal ion in the ligand system. The nuclease activity of the above metal complexes shows that Cu, Ni and Co complexes cleave DNA through redox chemistry whereas other complexes are not effective.

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Synthesis, spectral characterization of Schiff base transition metal complexes: DNA cleavage and antimicrobial activity studies

The survey highlights structural properties and biological studies of transition metal complexes derived from 4-aminoantipyrine. The most important results of extensive studies (syntheses, spectral, magnetic, redox, structural characteristics, antimicrobial and DNA cleavage) of the metal complexes with heterocyclic Schiff bases of 4-aminoantipyrine with some aldehydes and oximes are reviewed.

Transition metal complexes with Schiff-base ligands: 4-aminoantipyrine based derivatives–a review

Metal-based biologically active agents: Synthesis, characterization, antibacterial and antileukemia activity evaluation of Cu(II), V(IV) and Ni(II) complexes with antipyrine-derived compounds.

Neutral complexes of CuII have been synthesised from the Schiff bases derived from salicylidene-4-aminoantipyrine and PhNH2/substituted anilines. The structural features have been determined from their microanalytical, i.r., u.v.–vis., 1H-, 13C-n.m.r., mass and e.s.r. spectral data. All the complexes exhibit square-planar geometry. Their magnetic susceptibility measurements and low conductance data provide evidence for the monomeric and non-electrolytic natures of the complexes respectively. The electrochemical behaviour of the complexes in MeCN at 298 K was studied. The kinetic parameters were determined and are discussed. The X-band e.s.r. spectra of the complexes in DMSO at 300 and 77 K were recorded and their salient features are reported. The powder XRD diffraction patterns for all the complexes are found to be similar. The antimicrobial activity of the ligands and their copper complexes against the bacteria Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aerugenosa and Bacillus subtilis are also reported. The complexes have higher activities than those of the free Schiff bases. Moreover, they have higher activity than the control (ampicillin) except for Klebsiella pneumoniae and Pseudomonas aerugenosa.

Synthesis, structural characterisation and electrochemical and antibacterial studies of Schiff base copper complexes

Synthesis, characterization and antibacterial activity of some new complexes of Cu(II), Ni(II), VO(II), Mn(II) with Schiff base derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one

R.R. Premkumar

Papers

4-Aminoantipyrine schiff-base complexes of lanthanide and uranyl ions