Iron complexes formamide

Scheme 14 Catalytic hydrogenation of CO2 to formamide and formic acid by iron complex 29 (in situ generated)...

Methanol can be converted to a dye after oxidation to formaldehyde and subsequent reaction with chromatropic acid [148-25-4]. The dye formed can be deterruined photometrically. However, gc methods are more convenient. Ammonium formate [540-69-2] is converted thermally to formic acid and ammonia. The latter is trapped by formaldehyde, which makes it possible to titrate the residual acid by conventional methods. The water content can be determined by standard Kad Eischer titration. In order to determine iron, it has to be reduced to the iron(II) form and converted to its bipyridyl complex. This compound is red and can be determined photometrically. Contamination with iron and impurities with polymeric hydrocyanic acid are mainly responsible for the color number of the merchandized formamide (<20 APHA). Hydrocyanic acid is detected by converting it to a blue dye that is analyzed and deterruined photometrically. 

When labeled potassium cyanide reacted with the complex in an aqueous methanol solution, the bromide was rapidly replaced and the labeled cyanide ion entered slowly into the coordination complex. When the reaction was conducted at higher temperatures in ethylene glycol dimethyl ether as the solvent, the label was distributed among the benzyl isonitrile, benzyl formamide, and the polymer resulting from benzyl isonitrile and the iron isonitrile complexes. 

Nitrogenase, which catalyzes the reduction of N2 to two molecules of NH3, has a different molybdenum -iron cofactor (FeMo-co). It can be obtained by acid denaturation of the very oxygen-labile iron-molybdenum protein of nitrogenase followed by extraction with d i methyl formamide.655,656 The coenzyme is a complex Fe-S-Mo cluster also containing homocitrate with a composition MoFe7S9-homocitrate (see Fig. 24-3). Nitrogenase and this coenzyme are considered further in Chapter 24. 

First, 1 2 metal complexes of (mainly mono-) azo dyes, without sulfonic or carboxylic acid groups, and trivalent metals (see Section 3.11). The metals are preferably chromium and cobalt nickel, manganese, iron, or aluminum are of lesser importance. Diazo components are mainly chloro- and nitroaminophenols or amino-phenol sulfonamides coupling components are (3-naphthol, resorcinol, and 1-phe-nyl-3-methyl-5-pyrazolone. Formation of a complex from an azo dye and a metal salt generally takes place in the presence of organic solvents, such as alcohols, pyridine, or formamide. An example is C.I. Solvent Red 8, 12715 [33270-70-1] (1). 

Coupling of the lithium salts of allylic sulfones 9 by oxidation with iron(II) chloride dimethyl-formamide complex and Cope rearrangement of the 1,6-disulfones affords vicinal sulfones exclusively with threo configuration. In the case of 9c, a mixture of geometrical isomers of lie is obtained999. 

From conductivity measurements it may be assumed that in dilute methanolic and formamide solutions of iron(II) chloride all of the coordination sites of the iron are occupied by solvent molecules, whereas in ethylene glycol, dimethylformamide and pyridine the chloride ion also is to be found in the inner coordination sphere. If it is assumed that the equilibria prevailing in the solution are also frozen in during the rapid freezing of the solutions, and that new complex ions are not formed during... 

Dispersions can also be floccnlated by the addition of electrolytes, giving rise to systems containing large cations along with layers (or chains). Such systems cannot be prepared otherwise by direct intercalation. Intercalation compounds of TaS with complex aluminium oxycations and an iron sulphur cluster have been prepared in water-A -methyl-formamide solution [37]. 

For M = Ru, formamides and amines were the principal products. Substitution of Fe3(CO)i2 for Ru3(CO)i2 results in the formation of carbamate esters (ArNHCOOMe) as the major products, with ureas as the main by-products. Without the metal carbonyl, nitroarenes are recovered imchanged from the reaction mixture. An imido-alcoxycarbonyl complex was suggested as an intermediate in the reaction and the difference between iron and ruthenium was proposed to be due to the different facility of this intermediate to undergo protonation and reductive elimination to give carbamate, or insertion of CO into the M-N bond, followed by hydrogenation, affording formamide (Scheme 13) ... 

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