20074-52-6Relevant academic research and scientific papers
Effects of Temperature and Wavelength on the Primary Process in the Photo-oxidation of Iron(II) Ion
Logan, S. R.
, p. 615 - 617 (1990)
Experiments at 253.7 and 228.8 nm, each over a range of ca. 45 K, demonstrate that the primary quantum yield of photo-oxidation in deoxygenated acidic iron(II) solutions increases only very slightly with temperature, but that at the lower wavelength it is ca. 1.36 times greater.It is suggested that the excitation process involves the transfer of an electron to a shallow trap among the neighbouring solvent molecules, such that recombination of the electron with its geminate iron(III) ion is highly probable.It appears that temperature has little effect on the quantum yield because electron escape and recombination both depend on temperature to very similar extents and that the use of a higher-energy photon increases the quantum yield because then more and more distant traps are accessible for electron transfer.
Drosophila multicopper oxidase 3 is a potential ferroxidase involved in iron homeostasis
Wang, Xudong,Yin, Sai,Yang, Zhihao,Zhou, Bing
, p. 1826 - 1834 (2018/05/16)
Multicopper oxidases (MCOs) are a specific group of enzymes that contain multiple copper centers through which different substrates are oxidized. Main members of MCO family include ferroxidases, ascorbate oxidases, and laccases. MCO type of ferroxidases is key to iron transport across the plasma membrane. In Drosophila, there are four potential multicopper oxidases, MCO1–4. No convincing evidence has been presented so far to indicate any of these, or even any insect multicopper oxidase, to be a ferroxidase. Here we show Drosophila MCO3 (dMCO3) is highly likely a bona fide ferroxidase. In vitro activity assay with insect-cell-expressed dMCO3 demonstrated it has potent ferroxidase activity. Meanwhile, the ascorbate oxidase and laccase activities of dMCO3 are much less significant. dMCO3 expression in vivo, albeit at low levels, appears mostly extracellular, reminiscent of mammalian ceruloplasmin in the serum. A null dMCO3 mutant, generated by CRISPR/Cas9 technology, showed disrupted iron homeostasis, evidenced by increased iron level and reduced metal importer Mvl expression. Notably, dMCO3-null flies phenotypically are largely normal at normal or iron stressed-conditions. We speculate the likely existence of a similar iron efflux apparatus as the mammalian ferroportin/ferroxidase in Drosophila. However, its importance to fly iron homeostasis is greatly minimized, which is instead dominated by another iron efflux avenue mediated by the ZIP13-ferritin axis along the ER/Golgi secretion pathway.
Oxidation of phosphorus centers by ferrate(VI): Spectral observation of an intermediate
Hightower, Shaun M.,Lorenz, Bret B.,Bernard, Jonathan G.,Johnson, Michael D.
, p. 6626 - 6632 (2012/07/28)
The kinetics and mechanism for the oxidation of phosphite, hypophosphite, phenylphosphite, and trimethylphosphite by ferrate(VI) are reported. Hypophosphite is rapidly oxidized to phosphite which is slowly oxidized to phosphate, trimethylphosphite is oxidized to trimethylphosphate, and phenylphosphite is oxidized phenylphosphate. 18O induced shifts of the 31P NMR signals support oxygen transfer from ferrate(VI) to the phosphorus center during the oxidation process. Deuteration of the hydridic hydrogens in hypophosphite and phosphite resulted in significant kinetic isotope effects on the reaction rates. It is proposed that ferrate(VI) acts as a two-electron oxidant in conjunction with oxide transfer coupled with phosphorus hydrogen bond breaking for phosphite and hypophosphite and simple oxygen transfer for trimethylphosphite and phenylphosphite.
Characterisation of chemically lithiated heat-treated electrolytic manganese dioxide
Dose, Wesley M.,Lehr, Joshua,Donne, Scott W.
, p. 1827 - 1834 (2012/06/30)
Heat treated manganese dioxide is partially lithiated using butyl-lithium to determine the changes in crystal structure, chemical composition and morphology upon reduction, as a means of simulating its discharge behaviour in a non-aqueous battery cathode. As reduction proceeds, and lithium ions are inserted into the heat treated electrolytic manganese dioxide (EMD) structure, the material undergoes a phase transition to LiMn2O4. This new phase is further reduced to Li2Mn2O4. Reduction initially results in a 56% decrease in the surface area of the material; however, at higher degrees of reduction a slight increase in this value is observed, as a consequence of the strain placed on the lattice through continued lithium insertion.
Solvent extraction of some trace metals and iron with N-octyl-N,N- bis(dihexylphosphinylmethyl)amine
Cherkasov,Garifzyanov,Bazanova,Leont'eva
, p. 2080 - 2087 (2012/03/12)
The processes were studied of the solvent extraction of the ions of triply-charged trace elements including scandium, indium, gallium, and yttrium, as well as iron, with N-octyl-N,N-bis(dihexylphosphinylmethyl)amine solution in toluene, chloroform or methylene chloride from hydrochloric, nitric or perchloric acids aqueous solutions. The metals extraction dependence on the acid concentration showed that the best results were reached using perchloric acid. The calculation of partition coefficients of metals allowed us to reveal a high selectivity of the scandium extraction. The prospects of using the investigated bisphosphinylamine in the technology of extraction, concentration and separation of the trace metals ions was concluded. Pleiades Publishing, Ltd., 2011.
Redox reactions of K3[Fe(CN)6] during mechanochemically stimulated phase transitions of AlOOH
St??er, Reinhard,Feist, Michael,Patzwaldt, Kerstin,Menzel, Michael,Emmerling, Franziska
, p. 794 - 799 (2011/10/03)
Thermally induced redox reactions of K3[Fe(CN)6] (1) were investigated for a broad temperature range by thermal methods and structure analytical methods (ESR and M??bauer spectroscopy, X-ray Powder diffraction and XANES). Based on the influence of the mechanically activated and transforming matrices 2 and 3, redox processes can be tuned to form doped Al2O3 systems which contain either isolated Fe3 centres or redox active phases and precursors like (Al1-xFe x)2O3 (4), (Al3-xFe x)O4 (5), Fe3O4, Fe 2O3 and Fe0. The phase Fe3C and the chemically reactive C-species were detected during the reaction of 1. The final composition of the doped products of α-Al2O3 is mainly influenced by the chemical nature of the Fe doping component, the applied temperature and time regime, and the composition of the gas phase (N 2, N2/O2 or N2/H2). From the solid state chemistry point of view it is interesting that the transforming matrix (2 and 3) possesses both oxidative and protective properties and that the incorporation of the Fe species can be performed systematically.
X-ray crystallographic and photophysical properties of rhodamine-based chemosensor for Fe3+
Zhang, Lizhu,Fan, Jiangli,Peng, Xiaojun
, p. 398 - 402 (2009/07/18)
A fluorescent sensor for Fe3+, 2-[3′,6′-bis(ethylamino)-2′,7′-dimethyl-3-oxospiro[1H-isoindole-1,9′-[9H]xanthen]-2-((2-aminoethyl) methyl)]phenol, has been synthesized and characterized by 1H NMR, 13C NMR and X-ray crystal
The special features of the kinetics of oxidation of divalent iron during sulfuric acid leaching of pyrrhotine with the participation of nitrous acid
Markovich
, p. 25 - 28 (2009/04/14)
The kinetics of oxidation of divalent iron ions with molecular oxygen during pyrrhotine leaching in sulfuric acid solutions with the participation of nitrous acid as an activator was studied. The oxidation of Fe2+ to Fe3+ only occurr
Reactivity of ferrate(V) (FeV O43 -) with aminopolycarboxylates in alkaline medium: A premix pulse radiolysis
Noorhasan, Nadine N.,Sharma, Virender K.,Cabelli, Diane
, p. 1041 - 1046 (2008/10/09)
A premix pulse radiolysis technique was used to study the reaction between Fe(V) and APCs. Fe(V) reactions with glycine, IDA, NTA, EDTA and DTPA were measured at pH 12.5. Spectral results showed that Fe(V) is reduced to Fe(III); therefore, the reaction of Fe(V) with APCs proceeds via a concerted two-electron oxidation, which converts Fe(V) to Fe(III). The rate law for the oxidation of these APCs by Fe(V) is first-order with respect to each reactant at this pH. Fe(V) reactivity with APCs at pH 12.5 was found to increase in the order of tertiary 2 M-1 s-1 to 1.4 × 104 M-1 s-1. Both EDTA and DTPA reacted faster than NTA with Fe(V) and Fe(VI). The order of reactivity of amines with Fe(V) suggests that FeO43 - attacks at the nitrogen atom sites of the APCs, which leads to large differences in the rate constants. In addition, Fe(V) is approximately three- to five-orders of magnitude more reactive than Fe(VI). The reaction of Fe(V) with EDTA was studied as a function of pH (9.0-12.5). The rate constants increased as the pH decreased. The speciation of EDTA and Fe(V) were used to fit the data.
Iron(II) sulfate oxidation with oxygen on a Pt/C catalyst: A kinetic study
Okhlopkova,Kuznetsova
, p. 34 - 42 (2009/01/31)
The kinetics of iron(II) sulfate oxidation with molecular oxygen on the 2% Pt/Sibunit catalyst was studied by a volumetric method at atmospheric pressure, T = 303 K, pH 0.33-2.4, [FeSO4] = 0.06-0.48 mol/l, and [Fe 2(SO4)3] = 0-0.36 mol/l in the absence of diffusion limitations. Relationships were established between the reaction rate and the concentrations of Fe2+, Fe3+, H+, and Cl- ions in the reaction solution. The kinetic isotope effect caused by the replacement of H2O with D2O and of H+ with D+ was measured. The dependence of Fe2+ and Fe 3+ adsorption on the catalyst pretreatment conditions was studied. A reaction scheme is suggested, which includes oxygen adsorption, the formation of a Fe(II) complex with surface oxygen, and the one-electron reduction of oxygen. The last step can proceed via two pathways, namely, electron transfer with H+ addition and hydrogen atom transfer from the coordination sphere of the iron(II) aqua complex. A kinetic equation providing a satisfactory fit to experimental data is set up. Numerical values are determined for the rate constants of the individual steps of the scheme suggested.
