Other Iron Compounds

FIGURE 16-8 Lactotransferrin. (Reproduced with permission from S. J. Lippard and J. M. Berg, Principles of Bioinorganic Chemistry, University Science Books, Mill Valley, CA, 1994, p. 144.) 

FIGURE 16-9 Ferrichromes, Ferrioxamines, and Catechol Siderochromes. (a) Ferrichrome A. 

Malaman. B. Roques. A. Courtois, and J, Protas, Acta Cryst., 1976, B32, 1348. 

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A number of researchers, ° ° particularly in Japan, have been pursuing the oxides of iron as potential cathode materials for lithium cells. However, materials of the type LiFeOz have shown little ability for lithium removal. A number of other iron compounds have been studied over the years, including FeOCl, ° FePS3, ° KFeSz, and FeSz, but none showed much reversibility. Although metal phosphates have been studied for more than 20 years since the discovery of fast ion transport in NASICON, it is only recently that they have been considered as cathodes or anodes " of lithium batteries. 

Other Iron Compounds of Biological Interest.—The valency of iron in a range of ferredoxin extracts has been determined by ESCA. The structure of the Fe—S complex in a bacterial ferredoxin has been determined. The iron and sulphur atoms occupy alternate corners of a cube and four more sulphur atoms project from the iron atoms.Admission of oxygen to a neutral solution of Fe and excess penicillamine gives a red bis-complex, which is relatively stable in aqueous solution at room temperature. Quantitative... 

In the laboratory, the metal is traditionally added as pure ferrous salts, but at a larger scale, the use of these salts becomes prohibitively expensive, and normally Fe(NH4)2(S04)2, which contains 20% of active iron, is used. Other iron compounds have been employed, including solids such as goethite, which has been used, for example, for TCE destruction [63]. 

Calculation of Mossbauer parameters in iron oxides (and other iron compounds)... 

Other iron compounds for intravenous use Saccharated iron oxide is strongly alkaline and hypertonic if injected outside the vein it can cause marked local reactions. Significant serum hypophosphatemia has on occasion been observed during treatment, accompanied by reduced renal tubular reabsorption of phosphate. The mechanism of these changes, which were reversible after stopping the iron injections, has not been clarified (13). 

An interesting problem is presented by the fact that in myoglobin and hemoglobin the ferrous state of iron atoms is more stable than in other iron compounds. The answer is connected with the presence of the histidine residue shown in the preceding drawing and again (from a different view) in the adjacent drawing. 

Iron compounds in the blood absorb oxygen from the air and transport it to the tissues, where it is stored by other iron compounds. 

Under some conditions the film will contain inclusions of other iron compounds, such as hydroxides or phosphates, and as mentioned earlier may also have an overlay of precipitated or deposited compounds. 

An established interaction of clinical importance. Avoid ferrous sulfate and other iron compounds while taking cefdinir. It is not yet known how far apart these drugs must be separated to avoid this interaction, but 3 hours improves the situation considerably even if it does not totally solve it. There is no information to suggest that other eephalosporins interact in this way. 

Ferrous fumarate, gluconate, sulfate and other iron compounds can reduce the absorption of ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, norfloxacin, ofloxacin and sparfloxacin from the gut. Serum levels of the antibacterial may become sub-therapeutic as a result. Limited evidence suggests that fleroxacin is not affected and lomefloxacin is only minimally affected. Glemi-floxacin does not appear to interact when given 2 hours before or 3 hours after ferrous sulfate. No interaction appears to occur with iron-ovotransferrin. Zinc appears to interact like iron. 

An established and elinieally important interaetion. For maximal absorption give the iron at least 2 hours after the penicillamine. This should reduce their admixture in the gut. Do not withdraw iron suddenly from patients stabilised on penicillamine because the marked increase in absorption that follows may precipitate penicillamine toxicity. The toxic effects of penicillamine seem to be dependent on the size of the dose and possibly also related to the rate at which the dosage is increased. Only ferrous sulfate and fumarate have been studied but other iron compounds would be expected to interact similarly. 

Information is limited to these reports but it appears to be a elinieally important interaetion. Monitor the effeets of eoneurrent use and separate the doses of ferrous sulfate and levothyroxine by 2 hours or more on the assumption that reduced absorption accounts for this interaction. Monitor well. The same precautions would seem appropriate with any other iron compound. 

Iron oxide and other iron compounds were deposited on the sea bed. After many years, crustal changes and land deformations occurred repeatedly. As a result iron ore appeared on land. 

The reactivity of compounds of type (M) have been investigated in detail by Geoffroy et al. [174]. Although several products, including carbamates, could be obtained under proper conditions, this type of compound is relatively inert with respect to other iron compounds of the class here discussed [236] and is not likely to be an intermediate in any reaction promoted by Fe3(CO)i2. Thus we will not discuss the reactivity of compounds (M) any more. 

Iron(II) sulfate heptahydrate is a blue-green, crystalline compound used to prepare other iron compounds. What is the formula of iron(II) sulfate heptahydrate ... 

The conventional ceramics, brick, earthenware, and porcelains, are made from clay. Clay is a complex material, but its main component is a mineral called kaolinite. Pure kaolinite is a nice white powdery mineral. Such white clay is called China clay. Clay is often colored though, because it contains small quantities of colored material such as iron oxide (Fe Oj) that gives a brownish color. Other iron compounds present give grayish colors. All iron compounds turn into iron oxide (Fe Oj) when fired, and hence the earthenware made from grayish clay usually ends up with a brownish color. Ordinary clays contain in addition other minerals such as quartz, soda mica (paragonite), and potash mica (muscovite). 

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