Ferrous ion complexes

Barber et al. (61) have used FAB to study the antibiotics bleomycin A2 and B2 and their metal complexes. In particular, the ferrous sulfate complex of bleomycin A2 shows a pseudomolecular ion at mlz 1566, corresponding to the salt (A2 - H+ + FeS04) since the amide hydrogen of the histidine residue is lost on complexation. An ion at mlz 472 corresponds to the ferrous ion complexed to the surrounding ligands but lacking the disaccharide groups and the peptide chain. 

Phthalocyanine, ferrous ion complex, 86 Piperazine-containing crown macrocycles,... 

If the heat of adsorption of ethylene in ferrous-A zeohte is assumed to be approximately 40 kj mol it is possible to calculate, if jump diffusion occurs with an activation energy approximately half the heat of adsorption, that the hfe-time of an ethylene-ferrous ion complex is 2x 10 s. The Mossbauer event time is 9.8x 10 s during which time an ethylene molecule could make -5000 jumps at RT. 

ThioglycoHc acid can be identified by its in spectmm or by gas chromatography. Most of the by-products and self-esterification products are also detected by liquid chromatography, eg, thiodiglycolic acid, dithiodiglycolic acid, linear dimers, and polymers. Iron content can be assayed by the red sensitive complex of 1,10-phenanthroline [66-71-7] and ferrous ion of a mineralised sample. Ferric ion turns an aqueous ammonia solution deep red-violet. 

Bromide ndIodide. The spectrophotometric determination of trace bromide concentration is based on the bromide catalysis of iodine oxidation to iodate by permanganate in acidic solution. Iodide can also be measured spectrophotometricaHy by selective oxidation to iodine by potassium peroxymonosulfate (KHSO ). The iodine reacts with colorless leucocrystal violet to produce the highly colored leucocrystal violet dye. Greater than 200 mg/L of chloride interferes with the color development. Trace concentrations of iodide are determined by its abiUty to cataly2e ceric ion reduction by arsenous acid. The reduction reaction is stopped at a specific time by the addition of ferrous ammonium sulfate. The ferrous ion is oxidi2ed to ferric ion, which then reacts with thiocyanate to produce a deep red complex. 

SPECTROPHOTOMETRIC DETERMINATION OF HYDROXYUREA AS A COMPLEX WITH FERRIC CHLORIDE AFTER STABILIZATION BY FERROUS IONS... 

Heterocyclic compounds have in most cases been hydroxylated by modified forms of Fenton s reagent. For instance, EDTA or pyrophosphate have been added to the system to complex the ferrous ions. It has been shown in the reactions of bcnzenoid compounds, however, that addition of complexing agents does not affect the distribution of isomers obtained by Fenton s reagent,and therefore the hydroxyl radical must still be the hydroxylating species. 

This is a simplified treatment but it serves to illustrate the electrochemical nature of rusting and the essential parts played by moisture and oxygen. The kinetics of the process are influenced by a number of factors, which will be discussed later. Although the presence of oxygen is usually essential, severe corrosion may occur under anaerobic conditions in the presence of sulphate-reducing bacteria Desulphovibrio desulphuricans) which are present in soils and water. The anodic reaction is the same, i.e. the formation of ferrous ions. The cathodic reaction is complex but it results in the reduction of inorganic sulphates to sulphides and the eventual formation of rust and ferrous sulphide (FeS). 

Ferrous ion, iron(II), forms a complex with six cyanide ions, CN- the octahedral complex is called ferrocyanide. Ferric ion, iron(III), forms a complex with six cyanide ions the octahedral complex is called ferricyanide. Write the structural formulas for the ferrocyanide and the ferricyanide complex ions. 

Trace metals have to be removed, notably manganese, ferrous ions and zinc. This is often accomplished using the compound potassium hexacyanoferrate which predpitates or complexes the metals and, in excess, acts to inhibit growth and indirectly promotes dtric add production. The amount of potassium hexacyanoferrate required is variable depending on the nature of the ion content of the carbon source. 

If copper is present in the boiler FW (normally as the cupric ammonia complex ion), boiler surfaces are directly attacked by electrolytic reduction. In strongly alkaline conditions the ferrous ion is present as ferrous hydroxide [Fe(OH)2] ... 

Conceptual Flowsheet for the Extraction of Actinides from HLLW. Figure 5 shows a conceptual flowsheet for the extraction of all the actinides (U, Np, Pu, Am, and Cm) from HLLW using 0.4 M 0< >D[IB]CMP0 in DEB. The CMPO compound was selected for this process because of the high D m values attainable with a small concentration of extractant and because of the absence of macro-concentrations of uranyl ion. Distribution ratios relevant to the flowsheet are shown in previous tables, IV, V, VI, and VII and figures 1 and 2. One of the key features of the flowsheet is that plutonium is extracted from the feed solution and stripped from the organic phase without the addition of any nitric acid or use of ferrous sulfamate. However, oxalic acid is added to complex Zr and Mo (see Table IV). The presence of oxalic acid reduces any Np(VI) to Np(IV) (15). The presence of ferrous ion, which is... 

The acidity dependence is regarded as too slight to have any substantial bearing on the mechanism.) Cu(II) is a weak catalyst for the reduction. A mechanism involving attack of ferrous ion upon a Fe(II)-02 complex accounts for the kinetics, viz. 

The reductions by ferrous ion and mono- and bis-bipyridyl complexes of Fe(II) are also simple second-order with (for the Fe reaction at zero ionic strength ). 2 = TO X 10 exp(—12.1 X 10 /Rr) l.mole . sec . This reaction generates an intermediate capable of oxidising ethanol but the effect is suppressed by addition of Cl , Br and acrylonitrile, the latter being polymerised. 

The method is based on the oxidation of ferrous ions to ferric ions, which form a deep red complex with thiocyanate. 

The amount of ferrous ion produced is determined spectroscopically (at 510 nm) by formation of a highly colored complex with 1,10-phenanthroline. 

To examine the oxidation of Fe2+ to Fe3+, in the second experiment, 10 ml solution of 0.1 M ferrous ammonium sulphate was taken separately in four different beakers and sonicated for 15, 30, 45 and 60 min, before transferring the solution to a 25 ml volumetric flask and adding to it 10 ml of 0.01 M KSCN and making upto the mark with deionised water. The absorbance of these solutions was measured at 4-,iax 451 nm. Sonication of ferrous ammonium sulphate solutions oxidised ferrous ions to ferric ions, which in the presence of thiocyanate ions, produced an intense red coloured complex Fe(SCN)63, in proportions to the oxidation of ferrous ions to ferric ions, as could be seen in Fig. 10.1. 

The implications of these mechanistic studies for our understanding of environmental iron sequestration by siderophores is as follows. The hydroxyl containing aqua ferric ions will tend to form ferri-siderophore complexes more rapidly than the hexaaqua ion and ferrous ion will be sequestered more rapidly than the ferric ion. However, once in a siderophore binding site the ferrous ion will be air oxidized to the ferric ion, due to the negative redox potentials (see Section III.D). This also means that Fe dissolution from rocks will be influenced by mineral composition (other donors in the first coordination shell) as well as surface reductases in contact with the rock, and of course surface area (4,13). 

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