Iron carbonyl derivatives

In 1980 we published a survey (1) of our major results in this area as of late 1979. These results include extensive work on binuclear CF N PF complexes of cobalt (2,3,4,5) and nickel (6). This paper summarizes our more recent results in this area with particular emphasis on binuclear complexes of chromium, molybdenum, and tungsten as well as some new results on iron carbonyl derivatives. 

Photolysis is a convenient route - to iron carbonyl derivatives using FefCO), and this route may be better than oxidative addition to Fej(CO),2. One illustration is the 1 1 reaction of FefCO), with (Me2GeH)20 under mercury lamp irradiation for 1 h. in pentane to produce ... 

A compound with the same stoichiometry, (Bu Sb=SbBu )[Cr(CO)5]3), has been obtained from Bu SbCl2 and the analogous chromium decacarbonyl anion in which the Sb—Sb distance is also short (2.720 A) , and there is a third example in the iron carbonyl derivative 97, where the separation is 2.774 279.280... 

The Dewar-benzene iron carbonyl derivative [97], like perfluorobicyclo[2,2,0]hexa-2,5-diene itself, undergoes Diels-Alder addition to give [98a and b], with the chemical shifts shown. (53) [98a] is also formed, although in low yield, by the reaction of the preformed Diels-Alder adduct [99] with Na[(7r-C5H5)Fe(CO)2], confirming the stereochemistry of the addition. 

Dodecacarbonyltriiron (Fe3(CO)j2) is an important starting material in preparative iron carbonyl chemistry. Many of its reactions lead to rupture of the iron triangle to give mononuclear iron carbonyl derivatives. Thus the major products from the reactions of Fe3(CO)i2 with tertiary phosphines R3P [e.g., R = C0H5... 

Reaction of various iron carbonyls with Lewis bases yields a rather bewildering variety of iron carbonyl anions depending on the base, the iron carbonyl derivative, and the reaction conditions. A comprehensive... 

Similar attempted cleavage reactions of the lead-iron derivative with cadmium(II) iodide, copper(II) chloride dihydrate, cobalt(II) chloride hexahydrate, bismuth(III) bromide, and K[Pbl3] failed to give any iron carbonyl derivatives of these metals 198). The black air-sensitive derivative of divalent lead [PbFe(CO)4] has been obtained on treatment of [HFe(CO)4] with basic lead(II) acetate 199). 

R. Greatrex, N.N. Greenwood, Mossbauer spectra, structure, and bonding in iron carbonyl derivatives. Discuss. Faraday Soc. 47, 126-135 (1969)... 

Several interesting and significant papers concerning ligated CO appeared in 1985. Quantitative aspects of the reaction of OH" and OMe" with M(C0)s and M3(C0)i2 (M = Fe, Ru or Os) have been reported and the implications with regard to the water gas shift reaction were noted.A full account of a method for computing the most favourable initial site for nucleophilic attack on a transition metal complex has been described and applied to reactions of cationic iron carbonyl derivatives. Nucleophilic attack by H2O, OH" and H" on dicationic Ir carbonyl complexes yields cationic hydroxycarbonyl and formyl... 

Iron Carbonyl Derivatives.—The first binary metal nitrosyl cation, [Fe2(NO) ] +, stable only below - 20 °C, has been isolated as its [PF g] salt from the reaction of [Fe(CO)2(NO)2] with [NO][PFe]. It probably possesses a symmetrical structure with terminal NO ligands and an Fe=Fe double bond. ... 

Iron Carbonyl Derivatives.— The primary amines RNH2 (R=Et, Bu , Bu Bu, or Cy) and the secondary amines, pyrollidine and piperidine, react with [Fe(CO)5] to initially give adducts containing at least two molecules of amine. They are believed to be of an ion-pair or ion-cluster type, and are probably involved as intermediates in substitution and disproportionation reactions of [Fe(CO)5]. The complex [Fe(CO)3(Bu N=CHCH=NBu )] contains a a, tr-bonded diazabutadiene and not a [Pg.188]

The use of iron carbonyl derivatives in organic synthesis is often limited by the difficulty of separation of the iron complexes from the desired product at the end of the reaction. In the synthesis of aldehydes from alkyl halides using tetra-carbonylhydridoferrate, [HFe(CO)4] , this problem has been overcome by attaching the iron complex to an ion-exchange resin [equation (9)]. The resin converts alkyl halides into the homologous aldehyde in over 90% yield, and at the end of the reaction the iron complex is retained on the polymer. Allyl chlorides fail to react, and secondary alkyl halides undergo elimination. 

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