Tetracarbonyl diiron

Similarly, the reaction of dicyclopentadienyl-tetracarbonyl-diiron with 1-phenylphos-pholes yields phosphaferrocenes, although in lower yields ... 

Cyclopentadienyl iron(II) dicarbonyl dimer [di(cyclopentadienyl)tetracarbonyl-diiron), (C5HsFe)2(CO)4]... 

Diaryl thioketones are converted by diiron enneacarbonyl into products of orthometallation.141 Oxidative or photochemically induced deligation of these complexes provides an unusual and valuable synthetic entry into compounds in the uncommon isobenzothiophene category142,151 (Scheme 84). Moreover, the photochemical procedure provides the novel complex, (tetracyanoethylene)tetracarbonyl iron. The orthometallated complexes (68) can also be used to prepare isobenzofurans (see Section IV,B,5). 

The binary metal carbonyls are named by giving the name of the metal followed by the name carbonyl, with the number of carbonyl groups indicated by the appropriate prefix. For example, Ni(CO)4 is nickel tetracarbonyl, whereas Cr(CO)6 is chromium hexacarbonyl. If more than one metal atom is present, the number is indicated by a prefix. Thus, Co2(CO)8 is dicobalt octacarbonyl, and Fe2(CO)9 has the name diiron nonacarbonyl. 

The rearrangement occurs via the intermediate formation of 3-vinylcyclobutencs, which may be isolated, e.g. after treatment of the dichloro compounds with (nonacarbonyl)diiron, (nonacarbonyl)dicobalt or ethene[bis(triphenylphosphane)]nickel at room temperature.83 The straightforward method, however, seems to include both dechlorination and rearrangement, both reactions being promoted by (tetracarbonyl)nickel. 

Although nickel tetracarbonyl, iron pentacarbonyl, and diiron enneacarbonyl were already prepared in the 1890s, more than three decades passed before the chemistry of transition metal carbonyls took off. Undoubtedly, some parts of the chemical community had recognized that compounds such as Ni(CO)4 and Fe(CO)5 deserved special attention, in particular due to the use of Ni(CO)4 for the production of pure metallic nickel. However, since the structure of those compounds was unknown, transition metal carbonyls remained, more or less, a curiosity. 

First, cis- and trans-2-phenylmethylenecyclopropanes-3-d were shown to give trimethyl-enemethane complexes with the deuterium at a location consistent only with disrotatory ring-opening (Figure 41). Second, reaction of 2,2-diphenylmethylenecyclopropane with a variety of iron carbonyl reagents allowed isolation of the methylenecyclopropane iron tetracarbonyl complex. This compound could be shown to give the trimethylenemethane complex on reaction with trimethylamine-N-oxide or diiron nonacarbonyl, both of which... 

Tricarbonyliron complexes of cyclobutadienes. Roberts et al. have reported a useful synthesis of (2) by reaction of (1) with sodium tetracarbonyl-ferrate in THF. Use of diiron nonacarbonyl leads to (2) in lower yields. The... 

The use of sonolytic activation of Fe2(CO)9 in an inert solvent has proved to be a general process in the synthesis of a large number of (Ti-allyl)tricarbonyliron lactone complexes and provides an alternative route to those already established in the literature. Diiron nonacarbonyl failed to react with alkenyl epoxide (over a period of up to two weeks) in the absence of ultrasonication. Sonication may aid the breakdown of the diiron nonacarbonyl allowing generation of the highly reactive, coordinatively unsaturated tetracarbonyl iron species which after initial complexation to the double bond of the alkenyl epoxide can form the lactone complex. other pathways cannot, however, be ruled out. 

The starting materials for these complexes are dicarbonyl(cyclopentadienyl)-iron chloride (Fischer and Moser, 1970) and the dicarbonylcyclopentadienyl-iron anion [as the sodium salt (Green and Nagy. 1963)], both obtainable from tetracarbonyl (di-Tr-cyclopentadienyl)diiron which is available commercially. The reaction is carried out in tetrahydrofuran (THF). Equation (1) demonstrates the ease of manipulation of these substances in the preparation of an olefin complex from an epoxide. The tetrafluoroborate salt precipitates from ether. This reaction is also useful as a means of reducing expoxides stereospecifically to olefins with retention of configuration. The olefin is readily liberated from the complex by treatment with sodium iodide in acetone at room temperature for 15 min (Giering et ai, 1972). 

C4 3H4 oP2Pt, Cycloheptynebis(triphenylphosphine)platinum(O), 41B, 932 Cft4 32 6204, (10,10 -Biazulenyl)diiron tetracarbonyl, 42B, 687 C4 4H4 2Cl206P2Rh2, Di-M chloro-bis(triphenyl phosphite)(cyclo-octa-1,5-diene)dirhodium(I), 35B, 583... 

A 4% sodium amalgam is prepared from the careful addition of sodium (3 g, 130 mmol), in small portions, to mercury (650 g, 3.25 mol), which is rapidly stirred. The amalgam is allowed to return to room temperature over 1 h, and then a tetrahydro-furan (100 mL) solution of tetracarbonyl(dicyclopentadienyl)diiron (10.62 g, 30 mmol) is added in one portion and is efficiently stirred for 2 h. The amber tetrahydrofuran solution of sodium dicarbonyl(cyclopentadienyl)ferrate is separated from the amalgam and transferred to a new flask via syringe. This solution is cooled to 0 °C and l-bromo-2,2-di-methoxypropane (llg, 60 mmol) in tetrahydrofuran (10 mL) is added dropwise over 30 min. The yellow-brown solution is stirred at 0 °C for a further 30 min and then at room temperature for 3 h. The solvent is removed, and the residue is extracted with pentane (ca. 

A solution of sodium dicarbonyl(cyclopentadienyl)ferrate prepared from the dicarbonyl(T] -cyclopentadienyl)iron dimer [Cp(CO)2pe]2 (4.11 g, 11.6 mmol) and sodium amalgam (2%, 35.3 g) in tetrahydrofuran (80 mL) is added slowly at -78 °C to a solution of 4-bromo-2//-chromene-3-carbaldehyde (5.5 g, 23 mmol) in tetrahydrohiran (70 mL). The mixture is stirred at -78 °C for 1 h and then allowed to warm to room temperature over a period of 1 h. The solvent is evaporated in vacuo, and the residue is dissolved in diethyl ether/acetone (1 1) and subsequently purified by column chromatography on silica gel. With petroleum ether/diethyl ether (2 1) tetracarbonyl(dicyclopentadienyl)diiron is separated, whereas with diethyl ether/acetone (1 1) the alkenyl-Fp complex is obtained. The solvent is evaporated and the yellow-brown solid is dissolved in dichloromethane (200 mL), dried (magnesium sulfate), and the solution concentrated in vacuo to yield the q -alkenyl-Fp complex as a yellow-brown, amorphous solid 6.9 g (89%). ... 

By the addition of diiron nonacarbonyl, complex [(PhosN)Sn]2 is transformed to an iron tetracarbonyl adduct in which two stannavinylidenes arranged in a head-to-tail manner are subtended, one of which being coordinated to the iron atom by the mean of its lone pair (Eq. (6)). 

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