Addition of H(+) to a synthetic (mu-1,2-peroxo)diiron(III) model complex results in protonation of a carboxylate rather than the peroxo ligand. This conclusion is based on spectroscopic evidence from UV-vis, (57)Fe Mossbauer, resonance Raman, infrared, and (1)H/(19)F NMR studies. These results suggest a similar role for protons in the dioxygen activation reactions in soluble methane monooxygena...

The monomeric iron(II) amido derivatives Fe{N(H)Ar*}(2) (1), Ar* = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Pr(i)(3))(2), and Fe{N(H)Ar(#)}(2) (2), Ar(#) = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Me(3))(2), were synthesized and studied in order to determine the effects of geometric changes on their unusual magnetic properties. The compounds, which are the first stable homoleptic primary amides of iron(II), were obtai...

Low temperature electron paramagnetic resonance absorption spectra of randomly oriented preparations of cytochrome c peroxidase, ferrimyoglobin, ferrimyoglobin-azide, and ferrimyoglobin-fluoride are measured in various physical states. In general, the line width of resonance absorptions increases in relation to the physical state of preparation in the following order: concentrated solutions < w...

Iron-sulfur clusters are ubiquitous electron transfer cofactors in hydrogenases. Their types and redox properties are important for H(2) catalysis, but, recently, their role in a protection mechanism against oxidative inactivation has also been recognized for a [4Fe-3S] cluster in O(2)-tolerant group 1 [NiFe] hydrogenases. This cluster, which is uniquely coordinated by six cysteines, is situate...

Mossbauer spectra of a polycrystalline form of oxidized chloro-S, 10, 15,20-tetra(mesityl)porphyrinatoiron(lIl) [Fe(TMP)Cl], compound A, were recorded over a range of temperatures (4,2-195 K) and magnetic fields (0-6 T), These spectra of compound A exhibit magnetic features which are markedly different from those of the analogous protein complexes, horse radish peroxidase compound I (HRP-I) and...

The purpose of the present review is to provide an overview about the synthesis, characterization techniques involved and various physico-chemical properties of quinoxaline derivative metal complexes reported upto 2006 by several researchers. The synthesis of variety of metal complexes such as mono, bi and trimetallic complexes, homo bimetallic complexes, polynuclear, mixed metal and mixed liga...