Iron compounds Fe

Oxidation of the iron compound [Fe C(CH2)3 (CO)3] by Ce(IV) causes loss of trimethylenemethane which gives an adduct with tetracyanoethylene. The HCl addition, similarly to other electrophilic substitution reactions (e.g., acylation) ... 

Two compounds associated with particular industrial risks are iron(III) oxide, Fe202, and iron pentacarbonyl, Fe(CO). Chronic inhalation of iron(III) oxide leads to siderosis. Adequate ventilation and mechanical filter respirators should be provided to those exposed to the oxide. Iron pentacarbonyl is volatile and highly toxic. 

The abihty of iron to exist in two stable oxidation states, ie, the ferrous, Fe ", and ferric, Fe ", states in aqueous solutions, is important to the role of iron as a biocatalyst (79) (see Iron compounds). Although the cytochromes of the electron-transport chain contain porphyrins like hemoglobin and myoglobin, the iron ions therein are involved in oxidation—reduction reactions (78). Catalase is a tetramer containing four atoms of iron peroxidase is a monomer having one atom of iron. The iron in these enzymes also undergoes oxidation and reduction (80). 

This reaction is catalyzed by iron, and extensive research, including surface science experiments, has led to an understanding of many of the details (72). The adsorption of H2 on iron is fast, and the adsorption of N2 is slow and characterized by a substantial activation energy. N2 and H2 are both dis so datively adsorbed. Adsorption of N2 leads to reconstmction of the iron surface and formation of stmctures called iron nitrides that have depths of several atomic layers with compositions of approximately Fe N. There is a bulk compound Fe N, but it is thermodynamically unstable when the surface stmcture is stable. Adsorbed species such as the intermediates NH and NH2 have been identified spectroscopically. 

Vibrational spectra are often so complicated that assignment of a particular absorption to a given bond is difficult. One way to confirm that an assignment is correct is to carry out selective isotopic substitution. For example, we can replace a hydrogen atom with a deuterium atom. If an iron-hydride (Fe—H) stretch occurs at 1950 cm-1, at what energy will this stretch occur, approximately, for a compound that has deuterium in place of the hydrogen Refer to Major Technique 1, which follows these exercises. 

Like some other d-block metals, such as nickel, iron can form compounds in which its oxidation number is zero. For example, when iron is heated in carbon monoxide, it reacts to form iron pentacarbonyl, Fe(CO)5, a yellow molecular liquid that boils at 103°C. 

The reduced alkyl complexes are reoxidized by O2 to the iron(lll) alkyls. The corresponding diamagnetic phthalocyanine iron(ll) alkyl complexes, rFe(Pc)R), were prepared by two-electron reduction of Fe(Pc) by LiAIFl4 to give [Fe(Pc) (actually the Fe(I) phthalocyanine radical anion) followed by reaction with Mel, Etl or i-PrBr. The methyl compound, [Fe(Pc)CHi] was characterized by X-ray crystallography. ... 

In addition, several addition reactions have been reported for the iron complex [Fe(CNCH3)j] with hydrazine and with methylamine (99) the products (XVI) and (XVII), respectively, are described. A crystal structure study on the latter compound was carried out. 

Hemoproteins, such as hemoglobin and the cytochromes, contain heme. Heme is an iron-porphyrin compound (Fe -protoporphyrin IX) in... 

By far the most utilized Mossbauer isotope is Fe, particularly in (bio)inorganic chemistry. Most iron compounds are found in the oxidation states iron(ll) and iron (III), either with low-spin or high-spin electron configuration. The literature on the application of Fe Mossbauer spectroscopy in this field of research has been reviewed in several textbooks, which are referenced in Chap. 1. The present chapter is intended as a survey of the Mossbauer studies on iron compounds with less common, nevertheless increasingly interesting, valence and spin states. 

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