Iron carbonyl, Fe

Many metal carbonyls are available commercially. However, in some cases, the CVD investigator may find it more expedient (and sometimes cheaper) to produce them in-house. This is particularly true of the only two carbonyls that can be obtained by the direct reaction of the metal with CO (and consequently easy to synthesize), i.e., nickel carbonyl, Ni(CO)4, and iron carbonyl, Fe(CO)5. 

Reactions of PhC=CC=CPh with iron carbonyls [Fe(CO)s, Fe2(CO)9, or Fe3(CO)i2] give isomers of complexes Fe(CO)4 (diyne)2 (265), Fe2(CO)6 (diyne)2 (266), and Fe2(CO)7 (diyne)2 (267), to which structures analogous to those found for similar products obtained from C2Ph2 were ascribed all three isomers of the second complex were formed. The reactions of hexa-2,4-diyne and Fe(CO)s have been described in more detail. UV irradiation of mixtures of the two... 

Olefins readily displace CO groups from the iron carbonyls, Fe(CO)5, Fe2(CO)9, and Fe3(CO)12, to form complexes in which a C C bond of the olefin takes the place of each displaced CO group, and by donating its ir-electrons preserves the formal inert gas electron configuration of the iron atom in the complex. Acrylonitrile is the only reported example of a monoolefin complexing with iron in this way, but many complexes of iron with polyolefins are known. 

Exclusive formation of silylstyrenes 76 is achieved when the reactions of styrene and 4-substituted styrenes with HSiEt3 are catalyzed by Fe3(CO)i2 or Fe2(CO)9100. Other iron-triad metal carbonyl clusters, Ru3(CO)i2 and Os3(CO)i2, are also highly active catalysts, but a trace amount of hydrosilylation product 77 is detected in the Ru-catalyzed reactions and the Os-catalyzed reactions are accompanied by 3-12% of 77 (equation 31)100. Mononuclear iron carbonyl, Fe(CO)5, is found to be inactive in this reaction100. 

Other examples concern the interaction between iron carbonyles and potassium alkylthiolates that is accompanied by disproportionation. The anion radicals Fe2(CO)g, Fe3(CO)fi, Fe4(CO)i3, and Fe(CO)2 are formed (Belousov et al. 1987). The interaction of iron carbonyls Fe(CO)5, Fe2(CO)9, and Fe3(CO)i2 with (CH3)3NO occurs according to a one-electron redox-disproportionation scheme, giving rise to iron carbonyl anion radicals Fe2(CO)s Fe3(CO)n, l e3(CO)i2, and Fe4(CO)ii (Belousov Belousova 1999). 

Completely different behavior toward liquid NH3 is shown by the three iron carbonyls Fe(CO)s, Fe3(CO)9, and Fes(CO),2 (98, 99) and the two cobalt carbonyls Co2(CO)8 and Co4(CO)i3 (100). Between -21 and 0°C, Fe(CO)5 and liquid NH3 give a homogeneous, pale-yellow solution from which Fe(CO)5 may be recovered on evaporating off the NH3. The solution contains the carbamoyl complex NHJfOC Fe—CONHJ which cannot be isolated and which is formed by nucleophilic attack of an NH3 molecule on a CO ligand, followed by proton release (101). At 20°C after 14 days of reaction, (NHJ FefCOlJ and CO(NH2)2 are obtained (99) ... 

The simpler iron carbonyls, Fe(CO)5 and Fe2(CO)9, can also deoxygenate nitrobenzenes to anilines in an aqueous base-organic solvent system. With these carbonyls, however, a phase-transfer catalyst is not only unnecessary, its presence results in reduced product yields Furthermore, the nitro compound must be present to induce attack of hydroxide ion on Fe(CO)s t0 give HFe(CO)4 [and possibly HFe2(CO)8 ] (77). Such a phenomenon was also noted by Pettit and co-workers (23) in their excellent work on the use of water gas shift reaction conditions for the Fe(CO)5-cat-alyzed deoxygenation of nitrobenzenes. 

The first syntheses of carbonyl clusters containing an interstitial nitrogen atom involved the use of NO" " [Eqs. (45) and (46)] (3). In the case of rhodium, the major product was suggested to be [Rli6(CO)i4(NO)], but no further data have been reported on this. The reaction of NO with the mixture of iron carbonyls, Fe(CO)s and [Fe2(CO)8] , yielded two clusters... 

Iron bromide (FeBrg) Iron bromide (FeBrg) Iron bromide (FeBrg) Iron bromide (FeBrg) Iron bromide ((FeBrg)g) Iron carbonyl (Fe(CO)g)... 

Available forms (2) Powdered iron. Derived (a) by treatment of ore or scrap with hydrochloric acid to give ferrous chloride solution, which is then purified by filtration, vacuum crystallized, and dehydrated to ferrous chloride dehydrate powder this is reduced at 800C to metallic iron (briquettes or powder) of 99.5% purity (b) by thermal decomposition of iron carbonyl [Fe(C05)] at 250C (99.6-99.9% pure) (c) by hydrogen reduction of high-purity ferric oxide or... 

The neutral iron carbonyls, [Fe(CO)s, Fe2(CO)9, and Fe3(CO)i2] in reactions with aqueous alkali undergo reductions ... 

By far most of the organometallic chemistry of iron discussed in this article relies on Just a handful of commercially available precursors or complexes prepared directly from them. There are three commercially available iron carbonyls Fe(CO)s (1, iron pentacarbonyl), Fe2(CO)g (2,... 

Figure 8-56. TEM of a single iron nanocigar in a graphitic cell synthesized in the RF-CCP discharge at pressure 110 Pa (iron carbonyl Fe(CO)5 is a precursor of ferromagnetic iron core decomposition of carbon monoxide leads to individual encapsulation of the ferromagnetic iron core in a carbon/graphite matrix).

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