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New Neutral Schiff Base and Its Metal Complexes Derived from Mannich Base, N-(1-Morpholinobenzyl)acetamideRaman, N.

100%

Raman N. , Ravichandran S.

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2005

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tom Vol. 79 / nr 7

1107-1114

EN

New neutral Schiff base complexes of Cu(II), Co(II), Ni(II) and Zn(II) derived from 4-aminoantipyrine and N-(1-morpholinobenzyl)acetamide (Mannich base) have been synthesized. The structural features of the complexes have been confirmed by microanalytical data, IR, UV-Vis., NMR, EPR, and CV techniques. Electronic absorption spectra of the complexes indicate an octahedral geometry around the metal ion. Their magnetic susceptibility measurements and low conductance data provide evidence for the monomeric and neutral natures of the complexes respectively. The electrochemical behaviour, the anodic and cathodic potential and the number of electrons transferred were calculated using cyclic voltammogram. The X-band EPR spectrum of copper complex in DMSO at 300 K and 77 K was recorded and its salient features are reported. The antimicrobial activity of the ligand and its complexes has been extensively studied on microorganisms such as Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa and the fungi Aspergillus niger and Rhizoctonia bataicola by well-diffusion technique using DMF as solvent. It has been found that all the complexes have higher activity than the free ligand and the standard.

2

Synthesis, structural Characterization, Cyclic Voltammetric and Antibecterial Studies of Tetraaza 13-Membered Macrocyclic Copper(II), NIckel(II), Cobalt(II) and Zinc(II) Complexes DErived from the Schiff Base 3-Salicylidene-2,4-di(imino-4'-antipyrinyl)pe

100%

Raman N. , Thangaraja C.

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2005

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tom Vol. 79 / nr 7

1123-1134

EN

Atetraaza macrocyclic Schiff base (L), synthesized from the Schiff base 3-salicylidene- 2,4-di(imino-4_-antipyrinyl)pentane (3SDAP) and o-phenylenediamine, acts as a tetradentate ligand to form cationic solid complexes with Cu(II), Ni(II), Co(II) and Zn(II) metal salts in ethanol. All the synthesized complexes were characterized by microanalytical data, magnetic susceptibility measurements, IR, UV-Vis, 1H-NMR, 13C-NMR, ESR and mass spectral techniques. The IR and UV-Vis spectral data and magnetic susceptibility values of the complexes suggest that the [CuL]Cl2, [NiL]Cl2, [CoL]Cl2 and [ZnL]Cl2 complexes exhibit square-planar geometry. The electrolytic behaviour and monomeric nature of the chelates were confirmed from their molar conductance data and magnetic susceptibility values respectively. Cyclic voltammetric data of copper complex in DMSO reveal that the unusual oxidation states such as Cu(I) and Cu(0) are stabilized by the ligand system. The cyclic voltammogram of the nickel(II) complex was also recorded in DMSO solution and the salient features are reported. The X-band ESR spectra of the copper complex in DMSO solution at 300 K and 77 K were recorded and their spin Hamiltonian parameters were calculated. The in vitro biological screening effects of the investigated compounds were tested against some microorganisms. The metal complexes have higher activity than the free ligand and the standard.

3

Synthesis, Structural Characterization, Redox and Antimicrobial Studies of Schiff Base Copper(II), Nickel(II), Cobalt(II), Manganese(ii), Zinc(II) and Oxovanadium(ii) Complexes derived from benzil and 2-Aminobenzyl Alcohol

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Raman N. , Kulandaisamy A. , Jeyasubramanian K.

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2002

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tom Vol. 76 / nr 8

1085-1094

EN

Neutral complexes of Cu(II), Ni(II), Co(II), Mn(II), VO(II) and Zn(II) have been synthesized from the Schiff base derived from benzil and 2-aminobenzyl alcohol. The structural features have been arrived from their microanalytical, IR, UV-Vis, 1H NMR, Mass and ESR spectral data. All of the complexes exhibit square-planar geometry except the Mn(II) and VO(II) complexes. The Mn(II) chelate shows an octahedral environment and the VO(II) chelate exists in a square-pyramidal geometry. The monomeric and non-electrolytic nature of the complexes is evidenced by their magnetic susceptibility and low conductance data. The cyclic voltammogram of copper complex in acetonitrile solution shows two quasi reversible peaks for the Cu(II)/Cu(III) and Cu(II)/Cu(I) couples. The X-band ESR spectra of the Cu(II) and VO(II) complexes in DMSO at 300 and 77 K were recorded and their salient features are reported. The biological activity of the metal chelates against the bacteria Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa and Shigella flexneri are also reported. Most of the complexes have higher activity than that of the free Schiff base and the control.

4

Studies on DNA Cleavage and Antimicrobial Screening of Transition Metal(II) Complexes Derived from Tetradentate Schiff Base

80%

Raman N. , Dhaveethu Raja J. , Sakthivel A.

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tom Vol. 81, nr 12

2059-2067

EN

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 (H2L) derived from 4-aminoantipyrine, 3-hydroxy-4-nitrobenzaldehyde and 2-aminophenol. The structural features have been arrived from their elemental analyses, magnetic susceptibility, molar conductance, mass, IR, UV-Vis, 1H NMR and ESR spectral studies. The data show that the 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 behavior of copper and vanadyl complexes has been studied by cyclic voltammetry. The minimum inhibitory concentration (MIC) values of the in vestigated compounds indicate that the complexes have higher antimicrobial activity than the free ligand. The nuclease activity of the above metal complexes shows that only copper and nickel complexes cleave DNA through redox chemistry.