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Journal ArticleDOI

Mixed-ligand complex formation equilibria of Cu II with biguanide in presence of glycine as the auxiliary ligand

01 Sep 2006-Journal of Chemical Sciences (Springer India)-Vol. 118, Iss: 5, pp 411-418
TL;DR: In this article, the authors studied the mixed ligand complex formation of CuII with biguanide (Bg) and glycine (HG) and indicated the formation of the complexes: Cu(Bg)-2+, Cu(Cg)-1, Cg-2H), Cu(G)-2H) and G-1.
Abstract: Equilibrium study on the mixed ligand complex formation of CuII with biguanide(Bg) and glycine (HG), indicated the formation of the complexes: Cu(Bg)2+, Cu(Bg) 2 2+ , Cu(Bg-H)(Bg)+, Cu(Bg-H)2, Cu(Bg)(OH)+, Cu(Bg-H)(OH); Cu(G)+, Cu(G)(OH), Cu(G)2; Cu(G)(Bg)+, Cu(G)(Bg-H); (G)Cu(Bg)Cu(G)2+, (G)Cu(Bg-H)Cu(G)+, and (G)Cu(Bg-2H)Cu(G). From the deprotonation constants of coordinated biguanide (Bg) in the complexes Cu(Bg)(OH)+, Cu(Bg-H)(Bg)+ and Cu(G)(Bg)+, the Lewis basicities of the coordinated ligand species (Bg-H)-, OH- and glycinate (G-) were found to be of the order: (Bg-H)-≫ OH- > G-. Bridging (N1-N4, N2-N5) tetradentate mode of coordination by biguanide species Bg, (Bg-H)- and (Bg2H)2- was indicated from the occurrence of biguanide-bridged dinuclear mixed ligand complexes (G)Cu(Bg)Cu(G)2+, (G)Cu(Bg-H)Cu(G)+, (G)Cu(Bg-2H)Cu(G) in the complexation equilibria.

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TL;DR: The results clearly show that the copper binding energies cannot alone be the cause of the biochemical differentiation between Metf and PDI, and conclude that other factors such as pKa values and hydrophilicity of the compounds play a crucial role in their cellular activity.
Abstract: Metformin (Metf), the most commonly used type 2 diabetes drug, is known to affect the cellular housekeeping of copper. Recently, we discovered that the structurally closely related propanediimidamide (PDI) shows a cellular behavior different from that of Metf. Here we investigate the binding of these compounds to copper, to compare their binding strength. Furthermore, we take a closer look at the electronic properties of these compounds and their copper complexes such as molecular orbital interactions and electrostatic potential surfaces. Our results clearly show that the copper binding energies cannot alone be the cause of the biochemical differentiation between Metf and PDI. We conclude that other factors such as pKa values and hydrophilicity of the compounds play a crucial role in their cellular activity. Metf in contrast to PDI can occur as an anion in aqueous medium at moderate pH, forming much stronger complexes particularly with CuII ions, suggesting that biguanides but not PDI may induce easy oxid...

48 citations

Journal ArticleDOI
TL;DR: Results of a quantitative investigation of interactions between metformin and L-cysteine-copper complexes suggest that met formin could interact with biological copper, which plays a key role in mitochondrial function.

24 citations

Journal Article
TL;DR: The mixed ligand complexes of Mn(II),FeFe(II ), Co(II,Ni(II) and Cd (II) with 1-nitroso-2-naphthol (NNPhH) and amino acid L-phenylalanine (C 9 H 10 NO 2 ) were synthesized and characterized by Melting points, Solubility, Molar conductivity as mentioned in this paper.
Abstract: The mixed ligand complexes of Mn(II),Fe(II ), Co(II),Ni(II),Cu(II), Zn(II) and Cd (II) with 1-nitroso-2-naphthol (C 10 H 7 NO 2 ), symbolized (NNPhH)] and amino acid L-phenylalanine ( C 9 H 10 NO 2 ) , symbolized ( phe H), were synthesized and characterized by: Melting points, Solubility, Molar conductivity. determination the percentage of the metal in the complexes by flame(AAS), Molecular weight determined by Rast’s Camphor method, susceptibility measurements, Spectroscopic Method [FT-IR and UV-Vis], And Program [Chem office– CS .Chem.– 3D pro 2006] was used for draw compounds . The results showed that the deprotonated two ligands acts as a bidentate ligand , ( phe - ) was coordinated to the metal ions through the oxygen of the carboxylic group and the nitrogen of the amine and the 1-nitroso-2-naphthol ligand was coordinated to the metal ions through the oxygen and nitrogen atoms. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicate octahedral geometry for all the complexes. Key words: phenyl alanine , amino acid) Complexes , 1-nitroso-2-naphthol ,mixed ligands and Antibacterial Activities

10 citations

Journal ArticleDOI
TL;DR: In this paper, the ternary interactions of some phenoxyacetic acids derived from a herbicide, with the heavy metals present in soil in trace amounts has been realized by potentiometric measurements.
Abstract: The study of the ternary interactions of some phenoxyacetic acids derived from a herbicide, with the heavy metals present in soil in trace amounts has been realized by potentiometric measurements. The stability constants of the ternary complexes have been calculated at 25°C and ionic strength 0.1(NaNO3). The experimental results have confirmed the presence of one ternary hydroxide species MH−1(2,4-D)(2,4-MCPA) for Cu(II), Pb(II) and Zn(II) on one hand and MH−2(2,4-D)(2,4-MCPA) for Hg(II) on the other. The order of stability constants has been found to be: Cu(II)>Hg(II)>Pb(N)>Zn(N)>Cd(N). Finally, a quantum approach has been achieved by the semi-empirical AM1 method for the mercuric complex.

2 citations

References
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TL;DR: Twenty-one mixed-ligand complexes of cobalt(II) and Cobalt(III) have been screened for their antimicrobial, insect sterilizing and ovicidal activities and two complexes showed 50% inhibition of the conidial germination of Helminthosporium oryzae andAlternaria triticina, indicating their potential for use against human and plant pathogenic microbes.
Abstract: Twenty-one mixed-ligand complexes of cobalt(II) and cobalt(III) have been screened for their antimicrobial, insect sterilizing and ovicidal activities. Three of these cobalt(III) complexes exhibit broad antimicrobial spectra, including against human bacterial pathogens, dermatophytes and plant pathogenic fungi, while one exhibits feeble activity against a human pathogenic bacterium. These results have been compared with the activity of the corresponding cobalt(II) complexes, which have been found to be inactive, while the free ligands show reduced activity compared with the cobalt(III) complexes. Change in biological activity induced by a particular complex appears to be dependent on the composition of the first co-ordination sphere. Two of these complexes showed 50% inhibition of the conidial germination ofHelminthosporium oryzae andAlternaria triticina. These results indicate their potential for use against human and plant pathogenic microbes. Minimum inhibitory concentrations of the cobalt(III) complexes were determined. Three of these cobalt(III) complexes have been tested for insect sterilizing and ovicidal activities onDysdercus koenigi F. Positive sterilizing and ovicidal actions of [Co(BSOP)(NH3)2]NO3 (where BSOP—H2 is the Schiff base derived from salicylaldehyde and orthophenylenediamine) were obtained. Possible mechanism(s) of all these activities are discussed qualitatively.

10 citations