Triiron dodecacarbonyl

Triiron dodecacarbonyl has been obtained by three different methods the action of heat on the iron carbonyl Fe2(CO)9, oxidation of the anion HFe(CO)4 by various oxidizing agents, and treatment of iron pentacarbonyl with triethylamine followed by acidification of the reaction mixture. The method described below is based on the oxidation of the anion HFe(C0)4 with manganese dioxide. 

The reaction is carried out in a well-ventilated hood using a 2-1. three-necked flask fitted with a stirrer, nitrogen inlet, 

The suspension of manganese dioxide thus obtained is added to the buffered HFe(CO)4 solution. Heat is evolved, and the mixture becomes dark red in color. The oxidation process is allowed to proceed for 1 to 2 hours with stirring of the mixture and the excess of manganese dioxide is then decomposed by gradual addition of a solution of 40 g. of iron(II) sulfate 7-hydrate dissolved in 250 ml. of dilute sulfuric acid (about 2 N). The mixture, still red in color, is then treated with 300 ml. of 1 1 sulfuric acid. Stirring is continued until the black precipitate of triiron dodecacarbonyl is present in only a weakly colored, usually very pale green, supernatant solution. The product is then filtered and washed successively with 400 ml. of hot dilute ( 2 N) sulfuric acid, 200 ml. of 95% ethanol, and 150 ml. 

Triiron dodecacarbonyl is a precursor to a great variety of organoiron compounds. In this respect, it is frequently a superior reagent to iron pentacarbonyl.  

Publishing Corporation, New York, 1960. A review of the chemistry of this and other metal carbonyls. 

Triiron dodecacarbonyl can be used with advantage in place of iron pentacarbonyl in many syntheses because it often reacts under milder conditions and is easier to handle. The compound was originally prepared by treating the solution obtained by dissolving iron pentacarbonyl in 

Caution. The preparation should he performed in an efficient hood because iron pentacarbonyl is highly toxic. 

240 ml. of air-free water is placed in a 1-1. nitrogen-filled three-necked flask equipped with a stirrer and a reflux condenser. Then, 110 ml. (160 g. 0.82 mol) of iron pentacarbonyl and 83 ml. (60 g. 0.59 mol) of triethylamine are added, and the mixture is stirred and heated at 80° under nitrogen for 10 hours or overnight, whichever is more convenient. It is important that the proper temperature be maintained, because below 75° the reaction is incomplete and above 90° decomposition of the iron complex occurs. 

The triethylammonium hydrogen undecacarbonyltri-ferrate, [Et3NH][HFe3(CO)n], formed in this reaction is a deep red oil at 80° but solidifies when the mixture is cooled. The air-stable solid is washed several times with water and then dissolved in about 600 ml. of methanol. 

Inorganic Syntheses, Volume VIII Edited by Henry F. Holtzclaw, Jr. Copyright 1966 by McGraw-Hill Book Company, Inc. 

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Syntheses in Solvent Systems. Very few examples of syntheses of metal carbonyls in aqueous solution are reported. An exception is the preparation of Co2(CO)g from CoSO (66% yield) or C0CI2 (56% yield) and CO at 9.6—11 MPa (95—110 atm) in aqueous ammonia at 120°C for 16—18 h (101). Triiron dodecacarbonyl is prepared almost exclusively in aqueous solution. Quantitative yields of Fe2(CO)22 have been obtained by oxidising alkaline solutions of carbonyl ferrates with manganese dioxide (102—104). 

Triiron dodecacarbonyl Iron dodecacarbonyl- (8) Iron, di-p,-decacarbonyltri-, triangulo- (9) (17685-52-8)... 

The green triiron dodecacarbonyl is first eluted with ca. 3 1. of hexane, and the product is then eluted with 31. of 2 l(v/v) ether-hexane. The ether-hexane eluate is dried with anhydrous magnesium sulfate and evaporated. Distillation of the residual oil through a 15-cm. Vigreux column at reduced pressure affords a small forerun amounting to 1ml. or less and 17.9-20.0 g. (57-63%) of methyl 7-oxoheptanoate, b.p. 65-80° (0.1mm.), 1.4388 (Note 17). 

Triiron dodecacarbonyl, 16 63 Triiron tetroxide, 14 542 Triisobutylaluminum, 2 345t Triisobutylaluminum... 

Other than this system, metallated polysilanes contain the metal in low-valent oxidation states. Such systems have been reported by two groups. In 1995, an alternative functionalization route starting from poly[methyl(H)silylene] or poly[methyl(H)silylene-fo-methylphenylsilylene], 37, was reported, in which the polysilane Si-H moiety was hydro-silated using 1,3,5-hexatriene, affording the diene-modified polymer 67, which was metal functionalized using triiron dodecacarbonyl to give the iron tricarbonyl-polysilane coordination complex, 68.177... 

Activated mercaptans undergo desulfurization to hydrocarbons using cobalt carbonyl or triiron dodecacarbonyl as the metal complex, and basic phase transfer conditions (5 ). Acidic phase transfer catalysis has been little investigated, the first example in organometallic chemistry being reported in 1983 (reduction of diarylethylenes)( ). When acidic phase transfer conditions (sodium 4-dodecylcenzenesulfo-nate as the phase transfer catalyst) were used for the desulfurization of mercaptans [Fe3(CO)] 2 the metal complex],... 

Bis(trimethylsilyl)acetylene reacts with iron pentacarbonyl or with triiron dodecacarbonyl 73, 123) and with cyclopentadienylmanganese... 

The first carbidocarbonyl transition metal cluster to be recognized was Fe5C(CO),5 (1), which was isolated in very low yield from the reaction of triiron dodecacarbonyl with methylphenylacetylene and characterized by X-ray diffraction by Dahl and co-workers (2). The molecule (Fig. 1) comprises a square pyramidal Fe5 core with the carbide situated. 08 A below the center of a square face. Each iron atom bears three terminal carbonyls. Improved syntheses of 1 by protonation (5) or oxidation of [Fe6C(CO)l6]2-... 

A complex is formed, one in which triiron dodecacarbonyl is involved. 

Fe(NH3)6]Br2 When an excess of gaseous ammonia is passed through a freshly prepared solution of elemental iron in hydrobro-mic acid (40%), the bromide salt of the hexaammine iron(II) complex is deposited (86). The cation is also found in certain carbonyl ferrates, such as [Fe(NH3)6][Fe3(CO)u], which are obtained from the reaction of triiron dodecacarbonyl with ammonia in an autoclave (87). 

Tellurophene forms a charge-transfer complex with tetracyanoethylene in dichlorometh-ane3. Tellurophene4 and tetraphenyltellurophene5 reacted with triiron dodecacarbonyl in boiling benzene to produce tellurium-containing complexes of unknown structure. 

The first experiments which were carried out in the author s laboratory on organometallic phase-transfer catalysis were concerned with the reduction of nitrobenzenes (4) to anilines (5) by triiron dodecacarbonyl. Such a conversion was reported to occur in benzene containing methanol at reflux for 10-17 h, with the hydridoundecacarbonyltriferrate anion as the likely key intermediate (16). It was our expectation that the trinuclear iron hydride should be generated by phase-transfer catalysis and if so, effect reduction of nitro compounds (4) under exceedingly mild conditions. Indeed this was the case, as illustrated by the results shown in Table I (17). Not only is the reaction complete in 2 h or less using sodium hydroxide as the aqueous phase, benzene as the organic phase, and benzyltrieth-ylammonium chloride as the phase-transfer catalyst, but it occurs at room temperature and requires less metal carbonyl than when the reaction was... 

Diene iron tricarbonyl complexes are prepared by thermal or photochemical reaction of conjugated dienes with iron pen-tacarbonyl in the presence of TMANO, triiron dodecacarbonyl, ()]" -benzylidenacetone)iron tricarbonyl, diiron nonacarbonyl, or diiron nonacarbonyl absorbed on silica gel in the absence of solvent. The latter method is particnlarly usefiil for the preparation of complexes from polar electron-rich dienes and heterodienes. A reductive complexation of cycloheptatrienes using iron tricarbonyl and sodium borohydride to give cyclo-heptadiene iron tricarbonyl has been developed (Scheme 126). 

Whether a molecule is actually dynamically moving in the crystal or merely statistically disordered amonj several possible positions is a moot point as far as X-ray crystallc rapliy is concerned since the interaction lime of the X ray with the crystal is of the order of s. Taster than atomic movemenis. In the case oT triiron dodecacarbonyl we have olher evidence (see Chapter 15 Tor believing ihal ihe iron atoms are moving. But they need not—the disorder arises Troin the location of a molecule without a center of symmetry [Fe3(CO)i2] on a symmetry elemeni of the unit cell (the center of inversion)... 

Diiron enneacarbonyl, synthesis 46 Triiron dodecacarbonyl, synthesis 46 Tricarbonyl(cyclooctatetraene)iron, synthesis 47 Iron carbonyl complexes of triphenylphosphine, triphenyl-arsine, and triphenylstibine, synthesis 48 cis-Dinitrobis(ethylenediamine)cobalt(III) nitrite and nitrate, synthesis 60... 

The three reported preparations " of tricarbonyI(cyclo-octatetraene)iron involve the interaction of cycloocta-tetraene with iron pentacarbonyl. Although the yields arc good, considerable amounts of CgHg[Fe(CO)3]2 and CgHsFe2(CO)7 are often obtained as well. The reaction betw cen cyclooctatetraene and triiron dodecacarbonyl takes place more rapidly and gives a product of better purity. 

Two grams (0.007 mol) of triphenylphosphine is dissolved in 100 ml. of dioxane or tetrahydrofuran. One gram (0.0020 mol) of triiron dodecacarbonyl (synthesis 46) is added, and the mixture is stirred in an atmosphere of nitrogen at a temperature of about 70° for 45 minutes, or until the green color of the solution completely disappears. The mixture is then cooled to room temperature, filtered, and the browm residue washed with dioxane or tetrahydrofuran. The solvent is removed from the filtrate and washings by distillation vmder vacuum and the residue treated with 50 ml. of methanol or ethanol and cooled. A yellow crystalline product is obtained. The crystals are filtered, washed with two 10-ml. portions of petroleum ether, and sublimed under vacuum at 180°. The sublimate consists of [Fe (CO) 4- (C6Hs)3P ], which melts at 201 to 203° with decomposition. The residue from the sublimation is dissolved in a minimum amount of benzene, and the solution is filtered. The fil-... 

A mixture of fig. (0.0 Ifi mol) of triphenylarsine and 2 g. (0.004 mol) of triiron dodecacarbonyl (synthesis 4fi) is either refluxed in 150 ml. of tetrahydrofuran or heated at 80 to 90° in dioxane in an atmosphere of nitrogen for 45 minutes. The mixture is then cooled and filtered. The residue is rejected. It contains very little product, inasmuch as the arsine complexes are more soluble than the... 

Similar treatment of triiron dodecacarbonyl solutions with triphenylbismuthine and triphenylamine gives no isolable products. In the former case, the original green color of the solution is discharged in about 2 hours and an unidentifiable, brown, amorphous, uncrystallizable solid precipitates. In the latter case, a brown solid which contains no nitrogen is obtained. The triphenylamine is recovered unchanged. 

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