Iron(III)-NTA (nitrilotriacetic acid) solution shows high activity for oxidative degradation of 2'-deoxyribose in the presence of hydrogen peroxide, whereas its activity of Fe(III)-TFD A (2-aminomethyltetrahydrofuran-N,N-diacetic acid) is negligible under the same experimental conditions; however the latter solution exhibits abnormally higher reactivity for oxygenation reaction at 8-position of...

The Fe(iii)-binding constant of vosaroxin, an anticancer quinolone derivative, has been determined spectrophotometrically and compared with the analogous Fe(iii) complex formed with doxorubicin. The in vivo metabolic stability and iron coordination properties of the quinolones compared to the anthracylines may provide significant benefit to cardiovascular safety. The mechanism of action of both...

Redox-inactive metal ions that function as Lewis acids play pivotal roles in modulating reactivities of oxygen-containing metal complexes in a variety of biological and biomimetic reactions, including dioxygen activation/formation and functionalization of organic substrates. Mononuclear nonheme iron(III)-peroxo species are invoked as active oxygen intermediates in the catalytic cycles of dioxyg...

The iron mining regions of Brazil contain thousands of “iron ore caves” (IOCs) that form within Fe(III)-rich deposits. The mechanisms by which these IOCs form remain unclear, but the reductive dissolution of Fe(III) (hydr)oxides by Fe(III) reducing bacteria (FeRB) could provide a microbiological mechanism for their formation. We evaluated the susceptibility of Fe(III) deposits associated with t...

Aerobic organisms are faced with a dilemma. Environmental iron is found primarily in the relatively inert Fe(III) form, whereas the more metabolically active ferrous form is a strong pro-oxidant. This conundrum is solved by the redox cycling of iron between Fe(III) and Fe(II) at every step in the iron metabolic pathway. As a transition metal ion, iron can be "metabolized" only by this redox cyc...

Iron oxide catalysts supported on nanostructured silica SBA-15 were synthesized with various iron loadings using two different precursors. Structural characterization of the as-prepared Fe x O y /SBA-15 samples was performed by nitrogen physisorption, X-ray diffraction, DR-UV-Vis spectroscopy, and Mössbauer spectroscopy. An increasing size of the resulting iron species correlated with an increa...

Microbial degradation of organic matter, like any oxidation process, requires an oxidizing agent. The role of the latter may be played by oxygen (the most common electron acceptor). However, under microaerobic conditions (ground water, subsurface soil) the supply of oxygen is limited, which, in its turn, may limit the biodegradation rate. An alternative possibility is the use of other electron ...

We have investigated the reaction products of several iron(III) compounds with hydrogen peroxide, and have found that hydrogen peroxide promotes the formation of an oxo-bridged iron(III) species in the presence of methanol (electron donor), and carboxyl groups of the ligand systems play a role to give the tetranuclear iron(III) compound containing a bent Fe-O-Fe unit (O: oxo oxygen atom). Based...

To identify possible iron sources for bacteroids in planta, soybean (Glycine max L. Merr.) symbiosomes (consisting of the bacteroid-containing peribacteroid space enclosed by the peribacteroid membrane [PBM]) and bacteroids were assayed for the ability to transport iron supplied as various ferric [Fe(III)]-chelates. Iron presented as a number of Fe(III)-chelates was transported at much higher r...

Fe(III) oxides hydrated to various extents are the most abundant iron species in soil. Their extremely low solubility makes them almost unavailable to living organisms. To cope with iron deficiency, many microorganisms synthesize and secrete siderophores [1–5], which are low-molecular-weight compounds that specifically chelate Fe(III) to form stable complexes, into the soil (association constan...