When Fe2+ ions are added to rat-liver microsomes, lipid peroxidation begins after a short lag period. Fe2+-dependent peroxidation in the first few minutes of the incubation can be increased by adding Fe3+, ascorbic acid or Pb2+ ions; these stimulations are not additive. By contrast, Pb2+ ions inhibit peroxidation of microsomes in the presence of Fe3+/ascorbate or Fe3+-ADP/NADPH. In liposomes ma...

There is current interest in the bioinorganic chemistry of gallium owing to the extensive use of the element in medicine both as a therapeutic and diagnostic agent [1]. After numerous studies of simple gallium(III) salts [2, 3] recent investigations have focussed on coordination compounds of gallium halides with bio-relevant ligands including also many of the common nitrogen heterocycles [3, 4]...

Iron imbalance/accumulation has been implicated in oxidative injury associated with many degenerative diseases such as hereditary hemochromatosis, beta-thalassemia, and Friedreich's ataxia. Mitochondria are particularly sensitive to iron-induced oxidative stress - high loads of iron cause extensive lipid peroxidation and membrane permeabilization in isolated mitochondria. Here we detected and c...

The anticancer drug adriamycin binds iron and these complexes cycle to reduce molecular oxygen (Zweier, J. L. (1984) J. Biol. Chem. 259, 6056-6058). Optical absorption, EPR, and Mössbauer spectroscopic data are correlated with polarographic O2 consumption and chemical Fe2+ extraction measurements in order to characterize each step in this cycle. Fe3+ binds to adriamycin at physiologic pH formin...

A novel cyclophane consisting of methylene-bridged imidazolium- and pyrazole-moieties (calix[4]imidazolium[2]pyrazole) and two of its applications are presented. First, supramolecular recognition of an acetonitrile molecule by hydrogen bonding in the solid state is examined. Second, the capability to act as a ligand precursor is shown by the synthesis and characterisation of the respective dinu...

An oxo-bridged diruthenium(III) complex containing pyrazolato and pyrazole ligands is stable against ascorbic-acid reduction, induces apoptosis (60%, 48 h) against HeLa cells at 10 microM level and exhibits promising anti-angiogenic activity at its sub-cytotoxic concentrations. Other mononuclear ruthenium(III) complexes containing pyrazole ligands [Ru(pz)(4)X(2)](+) exhibit dual anti-angiogenic...

Spectroelectrochemical sensing a metal in two different oxidation states, both of which are weakly absorbing in the visible wavelength range, was demonstrated with ferrous and ferric ion. The sensor consisted of an indium tin oxide optically transparent electrode (ITO OTE) coated with a thin film of Nafion preloaded with the ligand 2,2'-bipyridine (bipy). Fe2+ in the sample partitioned into the...

The reaction of Co(NO(3))(2)·3H(2)O with pyridine-2,6-dicarboxylic acid and 3,5-dimethyl-1H-pyrazole in a 1:1:3 molar ratio affords the title complex, [Co(C(7)H(3)NO(4))(C(5)H(8)N(2))(3)]·H(2)O. The Co(II) atom is coordinated by one pyridine-2,6-dicarboxyl-ate chelating ligand and three 3,5-dimethyl-1H-pyrazole ligands in a distorted octa-hedral geometry. Hydrogen-bonding interactions involving...

The title compound, [NiCl 2 (C 4 H 6 N ) ]·2CH 3 CN, is a mononuclear octahedral Ni II pyrazole-based complex. Two acetonitrile molecules are linked to the complex by N—H...N hydrogen bonds. atom octahedrally coordinated four atoms of 4-methyl-1 -pyrazole ligands, forming equatorial plane. axial positions occupied two Cl atoms. CN was synthesized reaction with nickel(II) chloride hexahydrate in...

The first 2-pyridylmethyl pendant armed structurally reinforced cyclam ligand has been synthesized and successfully complexed to Mn2+, Fe2+, and Cu2+ cations. X-ray crystal structures were obtained for the diprotonated ligand and its Cu2+ complex demonstrating pentadentate binding of the ligand with trans-II configuration of the side-bridged cyclam ring, leaving a potential labile binding site ...