Synthesis, Characterization and Electrochemistry of the Novel Dawson-Type Tungstophosphate [H4PW18O62]7- and First Transition Metal Ions Derivatives.

ChemInform ◽  
2004 ◽  
Vol 35 (16) ◽  
Author(s):  
Israel-Martyr Mbomekalle ◽  
Bineta Keita ◽  
Yu Wei Lu ◽  
Louis Nadjo ◽  
Roland Contant ◽  
...  
2004 ◽  
Vol 2004 (2) ◽  
pp. 276-285 ◽  
Author(s):  
Israel-Martyr Mbomekalle ◽  
Bineta Keita ◽  
Yu Wei Lu ◽  
Louis Nadjo ◽  
Roland Contant ◽  
...  

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Wojciech Szczepanik ◽  
Marzena Kucharczyk-Klamińska ◽  
Piotr Stefanowicz ◽  
Anna Staszewska ◽  
Zbigniew Szewczuk ◽  
...  

Three model dipeptides containing 3-(2,3-di(pyridin-2-yl)quinoxalin-6-yl)alanine, 3-(dipyrido[3,2-a:2,3-c]phenazin-11-yl)alanine, and 3-(2,3-diphenylquinoxalin-6-yl)alanine were studied with respect to their ability to bind selected transition metal ions, such as Cu(II), Fe(II), Ni(II), Co(II), Mn(II), and Cr(III). It was found that only Cu(II) and Fe(II) ions could form stable complex species with the studied compounds. The ability to form the complexes correlated well with DNA damage experiments. Only the ferrous and cupric complexes are capable of generating both single- and double-strand scissions. However, double-strand breakages appear to be dominating lesions in the presence of hydrogen peroxide, especially for copper(II) containing systems. The quantity of breakage products in the presence ofN-(3-(dipyrido[3,2-a:2,3-c]phenazine-11-yl)alanyl)glycine complexes was the highest as compared to the complexes of the remaining compounds. Moreover, this ligand was the only one that cleaved DNA in the absence of either Cu(II) or Fe(II) ions.


Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.


Author(s):  
Mohammed Al-Amery1 ◽  
Ashraf Saad Rasheed ◽  
Dina A. Najeeb

Five new mixed ligand metal complexes have been synthesized by the reaction of divalent transition metal ions (Hg, Ni, Zn, Cu and Cd) with 2-(naphthalen-l-ylamino)-2-phenylacetonitrile (L1 ) and 1,10-phenanthroline (L2). The coordination likelihood of the two ligands toward metal ions has been suggested in the light of elemental analysis, UV-Vis spectra, FTIR, 1H-NMR, flam atomic absorption, molar conductance and magnetic studies. Results data suggest that the octahedral geometry for all the prepared complexes. Antibacterial examination of synthesized complexes in vitro was performed against four bacterias. Firstly, Gram-negative bacteria namely, Pseudomonas aerugin and Escherichia. Secondly, Gram-positive bacteria namely, Bacillus subtilis, Staphylococcuaurouss. Results data exhibit that the synthesized complexes exhibited more biological activity than tetracycline pharmaceutical.


Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.


Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne

Bond-length distributions are examined for thirty-three configurations of the metalloid ions and fifty-six configurations of the post-transition-metal ions bonded to oxygen. Lone-pair stereoactivity is discussed.


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