Cr Metal Complexes Research Articles

ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF SOME TRANSITION METAL COMPLEXES OF TWO LIGANDS DERIVED FROM AMINO ACIDS AND 2 – IMINO – 1 – METHYLIMIDAZOLIDIN – 4 – ONE

Plant extracts are most of the time used for antioxidant and antimicrobial studies. The Present study was designed to evaluate the activity of metal complexes as antioxidant and against some selected bacterial and fungal isolates. The new metal complexes of Cr (III) and Zn (II) containing ligands derived from Tyrosine, Leucine and 2 – imino – 1 – methylimidazolidin – 4 - one were selected. The test compounds were evaluated for their possible antioxidant activity through free radical scavenging activity via using 1,1 – diphenyl – 2 – picryl – hydrazyl (DPPH) method. All the complexes exhibited good to moderate activity with Cr (III) complex (CrL1) and (CrL2) as the best radical scavengers having the % inhibition value of 67.74 and 65.33 respectively. The complexes were also screened for their antimicrobial activities against two bacterial isolates and one fungal isolate (Streptococcus pneumoniae, Klebsiella pneumoniae and Aspergillus niger). The result showed that all the compounds have the moderate activity against the tested organisms.

Evaluation of antibacterial activity of macrocyclic metal complexes derived from dihydrazone and diketone

Synthesis of macrocyclic metal complexes of Cr(III) and Fe(III) by the condensation of benzil dihydrazone with 1H-indole-2, 3-dione.The metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility, thermal analysis, ESR, infrared, 1H NMR and UV-visible spectroscopy. On the bases of these studies, a fivecoordinate square pyramidal geometry is proposed for all the metal complexes. In vitro antibacterial activity of macrocyclic metal complexes exhibited good results.

Synthesis, Characterization, Antifeeding and Insect Growth-Regulating Activities of Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) Complexes with N-Acetylacetonyl-3-Aminocoumarin

Metal complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) have been synthesized using N-acetylacetonyl-3-aminocoumarin as chelating agent. The ligand behaves as a monobasic tridentate ONO donor towards Ni(II) and as monobasic bidentate ON donor towards other cations. All the complexes have been proposed to have octahedral geometry on the basis of analytical, thermal conductivity, spectral and magnetic data. The complexes have been screened against Spodoptera litura; F (Lepidoptera: noctuiidae) for antifeeding and insect growth-regulating activities The results show appreciable antifeeding and insect growth-regulating activities associated with metal complexation at higher and lower doses respectively. Keywords: Metal complexes; N-Acetylacetonyl-3-aminocoumarin; Antifeeding activity; Insect growth-regulating activity. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: http://dx.doi.org/10.3329/jsr.v2i3.4673 J. Sci. Res. 2 (3), 525-537 (2010)

Ligational, analytical and biological applications on oxalyl bis(3,4-dihydroxybenzylidene) hydrazone

The molecular modeling and parameters have been calculated to confirm the geometry of oxalyl bis(3,4-dihydroxybenzylidene) hydrazone, H 6L. The metal complexes of Cr 3+, VO 2+, ZrO 2+, HfO 2+, UO 2 2+ and MoO 2 2+ with H 6L have been prepared and characterized by partial elemental analysis, spectral studies (electronic; IR), thermal analysis and magnetic measurements. The data suggest the formation of polymer complexes with a unit [Cr(H 4L)(H 2O) 3Cl]·H 2O, [VO(H 4L)(H 2O) 2], [Hf(H 4L)(H 2O)]·H 2O [UO 2(H 4L)(H 2O) 2]·2H 2O [MoO 2(H 4L)] and [(ZrO) 2(H 2L)-(C 2H 5OH) 2]. The ligand behaves as a dibasic bidentate in all complexes except ZrO 2+ which acts as a tetrabasic tetradentate with the two ZrO 2+ ions. An octahedral geometry was proposed for the Cr 3+, HfO 2+, MoO 2 2+and UO 2 2+ complexes and square pyramid for VO 2+. The Cr 3+ is necessary to degrade the DNA of eukaryotic subject completely; the other complexes have little effect. H 6L was found suitable as a new reagent for the separation and preconcentration of ZrO 2+ ions from different water samples using flotation technique with satisfactory results.

Spectroscopic study of molecular structures of novel Schiff base derived from o-phthaldehyde and 2-aminophenol and its coordination compounds together with their biological activity

New Schiff base (H 2L) ligand is prepared via condensation of o-phthaldehyde and 2-aminophenol. The metal complexes of Cr(III), Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with the ligand are prepared in good yield from the reaction of the ligand with the corresponding metal salts. They are characterized based on elemental analyses, IR, solid reflectance, magnetic moment, electron spin resonance (ESR), molar conductance, 1H NMR and thermal analysis (TGA). From the elemental analyses data, the complexes are proposed to have the general formulae [M(L)(H 2O) n]· yH 2O (where M = Mn(II) ( n = 0, y = 1), Fe(II) ( n = y = 0), Co(II) ( n = 2, y = 0), Ni(II) ( n = y = 2), Cu(II) ( n = 0, y = 2) and Zn(II) ( n = y = 0), and [MCl(L)(H 2O)]· yH 2O (where M = Cr(III) and Fe(III), y = 1–2). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that H 2L is coordinated to the metal ions in a bi-negatively tetradentate manner with ONNO donor sites of the azomethine N and deprotonated phenolic-OH. This is supported by the 1H NMR and ESR data. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral (Cr(III), Fe(III), Co(II) and Ni(II) complexes), tetrahedral (Mn(II), Fe(II) and Zn(II) complexes) and square planar (Cu(II) complex). The thermal behaviour of these chelates is studied and the activation thermodynamic parameters, such as, E*, Δ H*, Δ S* and Δ G* are calculated from the DrTGA curves using Coats-Redfern method. The parent Schiff base and its eight metal complexes are assayed against two fungal and two bacterial species. With respect to antifungal activity, the parent Schiff base and four metal complexes inhibited the growth of the tested fungi at different rates. Ni(II) complex is the most inhibitory metal complex, followed by Cr(III) complex, parent Schiff base then Co(II) complex. With regard to bacteria, only two of the tested metal complexes (Mn(II) and Fe(II)) weakly inhibit the growth of the two tested bacteria.

Synthesis, characterization and biological activity of (E1, E2) N1 ,N2 - bis[1-(3,4- dihydroxyphenyl)ethylidene]oxalohydrazide complexes: New method for ZrO2+ separation

The bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated to confirm the geometry of (E 1 , E 2 ) N 1 ,N 2 - bis[1-(3,4-dihydroxyphenyl)ethylidene]oxalohydrazide, H 6 DPOH. The metal complexes of Cr 3+ , VO 2+ , ZrO 2+ , HfO 2+ , UO 2 2+ and MoO 2 2+ with H 6 DPOH have been prepared and characterized by partial elemental analysis, spectral studies (electronic; IR), thermal analysis and magnetic measurements. The data suggest the formation of [Cr(H 4 DPOH)(H 2 O) 3 Cl]H 2 O, [VO(H 4 DPOH)(H 2 O) 2 ], [Hf(H 4 DPOH)(H 2 O)]H 2 O [UO 2 (H 4 DPOH)(H 2 O) 2 ] 2 H 2 O [MoO 2 (H 4 DPOH)] and [(ZrO) 2 (H 2 DPOH)(C 2 H 5 OH) 2 ]. H6DPOH behaves as a dibasic bidentate in all complexes except ZrO 2+ which acts as a tetrabasic tetradentate for the two ZrO 2+ ions. An octahedral geometry was proposed for the Cr 3+ , HfO 2+ , MoO 2 2+ and UO 2 2+ complexes and square pyramid for VO 2+ . The Cr(III) or VO 2+ complexes are necessary to degrade the DNA of Eukaryotic subject completely; the other complexes have little effect. H 6 DPOH was found applicable as a new reagent for the separation and preconcentration of ZrO 2+ ions from different water samples using flotation technique with satisfactory results.