Iron complexes reductive dimerization

However, in acetonitrile with the ratio PhS Fe 5 1, the mononuclear tetrahedral iron complex [Fe(SPh)4]2 is formed first, which reacts with sulfur to form the iron(III) dimer [Fe SPh),]2-according to equations (67) and (68). No further reaction takes place, but addition of methanol facilitates the reductive elimination of PhSSPh from the dimer to give the 2Fen2FenI cubane complex as in equation (69). Although this series of reactions has been written for PhS-, it appears similar reactions take place with alkyl as well as aryl thiolates. 

Treatment of 2,2,4,4-tetramethyl-3-thietanone with diiron nonacarbonyl gives the binuclear iron complex 381. 2,2-Dimethyl-3-thietanone undergoes oxidative dimerization to 382 on treatment with potassium ferricyanide. Methylene-3-thietanones such as 359 add chlorine from thionyl chloride to the carbon-carbon double bond. 2,2,4,4-tetramethyl-3-thietanone is converted to the 3-thione in 14% yield by treatment with hydrogen sulfide-hydrogen chloride. Electrochemical reduction of the thione produces radical anions. 

The generation of the precursors for cyclopentadienyl-silanol-functionalized iron complexes involves the formation of the corresponding iron anion in a first step [6]. 2a is obtained by reductive cleavage of the methoxysilyl-cyclopentadienyl-substituted iron dimer 1 with sodium amalgam in THF (Scheme 1). This reaction is restricted to alkoxysilyl-cyclopentadienyl-fiinctionalized iron anions because of the limited access to the corresponding Si-H-functionalized iron dimers. 

The 1,3-butadiene cyclo-dimerization reaction can be performed by iron complexes, prepared in situ by the reduction of [Fe2(NO)4Gl2l with metallic zinc, dissolved in [G4GiIm][BF4] or [G4GiIm][PF6] ILs (Scheme 30). The linear dimerization of 1,3-butadiene can also be performed with Pd(ii) salts (chloride or acetate)/PPh3 catalyst precursor dissolved in [G4GiIm]BF4 or [G4GiIm]PF6 to produce 1,3,6-octatriene (Scheme 31). ... 

Treating pentacarbonyliron with dicyclopentadiene affords the dicarbonyl (ri -cyclopentadienyl)iron dimer [Cp(CO)2pe]2. Reduction of the latter with sodium amalgam provides the nucleophilic dicarbonyl(r -cyclopentadienyl)iron anion [Cp(CO)2Fe]. Allylic halides or tosylates can be reacted with this Fe(0) complex to afford ri -allyl-Fp-iron complexes (Fp = Fe(CO)2Cp, Scheme... 

The commercially available (tj5-cyclopentadienyl)iron dicarbonyl dimer 1 is the source of the carbonyl(//5-cyclopentadienyl)iron(L) moiety. Reductive or oxidative cleavage of 1 provides reactive monomeric species that may be converted into iron-acyl complexes as described in the following sections (see also Houben-Weyl, Vol. 13/9a, p208). 

Batch, Dance and Holm have prepared a number of iron-bis-dithiolene chelates for which magnetic susceptibility measurements indicate spin exchange in dimeric units in the solid (79). In addition polarographic data strongly suggest that the dimeric units are retained in dichloromethane solution. Starting with the neutral complex, two one-electron reductions are observed, followed by a two-electron reduction. Presumably these steps correspond to... 

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