Reactions of Iron m

The oxidations of JV-alkylphenothiazines (PTZ) by Fe + and [Fe(CN)e] have been reported. The reactions are of considerable interest since they give rise to cation radicals which are long lived in aqueous acidic media, e.g. (4), where 

Rate and thermodynamic data are presented in Table 1. Correlation of the data with the Marcus theory has enabled estimates to be made for the reduction potentials and the intrinsic parameters of the cation radicals which are formed in the rate-limiting reaction. A similar procedure has been adopted in an analysis of the outer-sphere oxidation of ascorbic acid by a series of one-electron acceptor metal complexes. In this case, however, reactions of both HgA and HA are 

Catalysis by metal complexes of the oxidation of various organic substrates by alkaline hexacyanoferrate(iii) has been the subject of several papers. In the mechanism of oxidation of alcohols catalysed by a complex is formed 

---

The rate constants for the formation of FeCl + from Fe and Cl have been measured as a function of solvent composition in water-methanol mixtures. As with most complexation reactions of iron(m), the apparent rate constant Arobs is dependent on pH, indicating the existence of two parallel pathways (Scheme 1). Both... 

L = NHa, NHaMe, NHaEt, NHaPr, or ien, X = Cl or Br) it has been shown that, whereas the forward reactions involve the reaction of iron(m)-halide complexes, the reverse reaction when studied in at least a thirty-fold excess of reductant exhibits second-order kinetics, with the rate law... 

The kinetics and mechanism of the reaction of iron(m) with thiocyanate have received further attention. ... 

Fe—Fe bond can be assigned structures 201 or 202 based on spectral data. The other product of this reaction is 193 (R = r-Bu), however, it is produced in minor amounts. Complexes 199 (R = R = r-Bu, R = Ph, R = r-Bu) were obtained. Reaction of 146 (M = Mo, R = Ph, R = R = Ft, R = r" = Me) with (benzyli-deneacetone)iron carbonyl gives rise to the bimetallic complex 200 (M = Mo), which reacts further with the free phosphole to form the bimetallic heteronuclear sandwich 203. The preferable coordination of the molybdenum atom to the dienic system of the second phosphole nucleus is rather unusual. The molybdenum atom is believed to have a greater tendency to coordinate via the trivalent phosphorus atom than via the dienic system. 

Imidazo[2,l- ][l,7]naphthyridines can be prepared by reaction of the ketonaphthyridinium salt 300 with ammonium acetate and iron(m) chloride at high temperature (Equation 102) <2001AJC105>. Reaction of the />m-fused [2,7]naphthyridine 301 with benzylamine or 2-phenylethylamine in the presence of silica gel gives a pentacyclic imidazonaphthyridine 302 (Equation 103) <2001H(54)721>. 

The [4+ 4]-homolog of the [4 + 2]-Alder-ene reaction (Equation (48)) is thermally forbidden. However, in the presence of iron(m) 2,4-pentanedioate (Fe(acac)3) and 2,2 -bipyridine (bipy) ligand, Takacs57 found that triene 77 cyclizes to form cyclopentane 78 (Equation (49)), constituting an unprecedented formal [4 + 4]-ene cycloisomerization. The proposed mechanism for this transformation involves oxidative cyclization followed by /3-hydride elimination and reductive elimination to yield the cyclized product (Scheme 18). 

An astonishing recent discovery is that there are bacteria living deep in the Earth s crust. Colonies of anaerobic bacteria have been isolated from boreholes 1,500 m deep in basaltic rock formations. The bacteria use H2 as electron donor, which may originate from fermentation of organic matter, or from a purely inorganic reaction of iron of the Earth s core with water (Stevens and McKinley 1995 Anderson et al. 1998). 

Galvez, N. Barr6n,V. Torrent,. J. (1999 a) Effect of phosphate on the crystallization of hematite, goethite, and lepidocrodte from ferrihydrite. Clays Clay Miner. 47 304-311 Gancedo, J.R. Grada, M. Marco, J.F. Pala-dos, J. (1988) Comparative Mossbauer and SEM study of the corrosion reaction of iron and weathering steel in SO2 polluted atmospheres. Hyperfine Interactions 41 637-640... 

We can now make sensible guesses as to the order of rate constant for water replacement from coordination complexes of the metals tabulated. (With the formation of fused rings these relationships may no longer apply. Consider, for example, the slow reactions of metal ions with porphyrine derivatives (20) or with tetrasulfonated phthalocyanine, where the rate determining step in the incorporation of metal ion is the dissociation of the pyrrole N-H bond (164).) The reason for many earlier (mostly qualitative) observations on the behavior of complex ions can now be understood. The relative reaction rates of cations with the anion of thenoyltrifluoroacetone (113) and metal-aqua water exchange data from NMR studies (69) are much as expected. The rapid exchange of CN " with Hg(CN)4 2 or Zn(CN)4-2 or the very slow Hg(CN)+, Hg+2 isotopic exchange can be understood, when the dissociative rate constants are estimated. Reactions of the type M+a + L b = ML+(a "b) can be justifiably assumed rapid in the proposed mechanisms for the redox reactions of iron(III) with iodide (47) or thiosulfate (93) ions or when copper(II) reacts with cyanide ions (9). Finally relations between kinetic and thermodynamic parameters are shown by a variety of complex ions since the dissociation rate constant dominates the thermodynamic stability constant of the complex (127). A recently observed linear relation between the rate constant for dissociation of nickel complexes with a variety of pyridine bases and the acidity constant of the base arises from the constancy of the formation rate constant for these complexes (87). 

Davison, J. B., and Bellama, J. M., Inorg. Chim. Acta 14, 263 (1975) (Reaction of iron carbonyls with bis-5,8-trimethylsilyl-l,3,6-cyclooctatriene). 

For example, if a dilute solution of acidified potassium manganate(vn) (pale purple) is added to a solution of iron(n) sulfate, a colour change takes place as the reaction occurs (Figure 3.19). The iron(n) sulfate (pale green) changes to pale yellow, showing the presence of iron(m) ions. 

Iron metaniobates(iv) with structures of the natural minerals, ilmenite and pseudo-brookite have been prepared by direct reaction of the oxides under vacuum at 1000—1100°C. The compounds are stable in air up to 500°C, but are oxidized at higher temperatures.326 a-Sr3Fe07 x has been found to be isostructural with Sr3Ti07.327 Synthesis and thermal decomposition of iron(m) normal selenite mono-or tri-hydrate, Fe203,3Se02,xH20 (x = 1 or 3) have been reported.328... 

Among comparative kinetic studies, the kinetic advantage method has been used systematically in several cases. It has been developed for the first time for investigating the ET versus SN2 problem in the reaction of iron(i) and cobalt(n) porphyrins with primary butyl halides (Lexa et al., 1981), yielding the corresponding a-butyl-iron(m) and cobalt(m) complexes according to the overall reaction (142). 

On the other hand, polytellurides only seem to oxidize metals to the +1 or +11 state. Reaction of equimolar amounts of Te4 with M(CO)6 results in disubstitution of CO forming a cu-complex (CO)4MTe4 (M = Cr (45), W (47)47). If an excess of metal carbonyl is used in the presence of poly-telluride anion, multinuclear products can be isolated and metal-metal bonds can also form, leading to clusters. Careful manipulation of reaction conditions and choice of the polychalcogenide anion used makes possible partial oxidation of the metal centers and cluster formation. The reaction of iron carbonyls with polytelluride anions can lead to a wide array of cluster compounds, the identities of which are controlled by the stoichiometries and compositions of the starting telluride anions. For instance, reaction of [Fe(CO)5] with Te2 leads to the formation of [Fe3(CO)9(ju.3-Te)]2 (48),48 whereas its reaction with increasing amounts... 

A time resolution of approximately 10 ps is possible with the CFMIO method, although at such short times the mixing and chemical reaction take place simultaneously and the analysis becomes more complicated. Nonetheless, the method was used successfully in a study of the reactions of iron(III) and ruthenium(III) polypyridine complexes with several transition metal cyano compounds [3], but each experiment required approximately 300 mL of solution. The measured rate constants for electron transfer exceeded 3 x 10 M s . ... 

Free carbenes can also be avoided by using transition-metal-carbene complexes L M=CRR (L = a ligand, M = a metal), which add the group CRR to double bonds.An example is the reaction of iron carbene 215. ... 

This complex can also be prepared by the ligand exchange reaction of (T M-phenyl-3-buten-2-one)(tricarbonyl)iron with 1,4-butadiene as described below [82]. 

WEL/SAL] Wells, C. F., Salam, M. A., Complex formation between iron(Il) and inorganic anions. Part II. The effect of oxyanions on the reaction of iron(II) with hydrogen peroxide, J. Chem. Soc. A, (1968), 308-315. Cited on pages 332, 505. 

FIGURE 8.20 Proposed oxidation products of theaflavin with iron. (From O Coinceanainn, M., Bonnely, S., Baderschneider, B., and Hynes, M. J. 2004. Reaction of iron(III) with theaflavin Complexation and oxidative products. J. Inorg. Biol. 98 657-63. With permission.)... 

Schwab, G. M. Philnis, J. "Reactions of Iron Pyrite Its Thermal Decomposition, Reduction by Hydrogen, and Air Oxidation," J. Amer. Chem. Soc. 1947, 69, 2588. 

The uncharged Fe(OH)3 (H20)3 species does not repel other iron(m)-water ions and is therefore less water soluble than the charged ions. It can lose four water molecules and precipitate as FeOOH. FeOOH is more stable than Fe(OH)3. These hydrolysis reactions of iron and especially of aluminium are primary factors in the production and control of soil acidity. 

Knoevenagel and Polack733 have given directions for the preparation of aromatic sulfinic anhydrides by the action of acetic anhydride on a suspension of the dry sulfinic acid in a little acetic acid. The reaction is catalysed by sulfuric acid or a 0.1% solution of iron(m) chloride in glacial acetic acid or acetic anhydride. Benzene-, / -toluene-, / -xylene-, pseudocumene-, mesitylene-, and / -bromo- and / -iodo-benzene-sulfinic anhydride have been obtained in this way. 

Moisture must be completely excluded because sodamide readily becomes coated with sodium hydroxide it is thus advisable to prepare the reagent shortly before use by reaction of sodium with anhydrous liquid ammonia192 in the presence of iron(m) chloride or nitrate.190 2-Butyn-l-ol (7) is then obtained in 80% from 3-chloro-2-buten-l-ol (6) by way of its sodium salt, the original starting material being l,3-dichloro-2-butene 193... 

D. Solomon, P. Peretz, and M. Faraggi, Chemical Properties of Water-Soluble Porphyrins. 2. The Reaction of Iron(III) Tetrakis(4-N-methylpyridyl)porphyrin with the Superoxide Radical Dioxygen Couple, J. Phys. Chem., 86 (1982) 1842. 

---