Trinuclear iron complex

The black trinuclear iron complex Fe3(CO)8(Ph2C2)2> one of two isomers obtained by the reaction of excess tolane with dodecacarbonyl iron, contains not only a heterocyclic iron atom similar to that first observed by Hock and Mills (36) but also has two iron atoms lying symmetrically on either side of the heterocyclic ring (42) in a manner similar to that suggested by the author on theoretical grounds (20) (Fig. 9). 

This technique was used to resolve trinuclear iron complexes by using sephadex SP-C25 as the stationary phase and an aqueous solution of (+)-tartratoantimonate (111) as eluant.t °° ... 

Barton et al. used zinc (Zn) as a reductant. They isolated a trinuclear iron complex, Fe"Fe 20(OAc)6(py)i,s, from a reaction system containing iron powder, carboxylic acids, and H2S in aqueous pyridine under 1 atm O2 and found that it oxidized alkanes in the presence of Zn, pyridine, and acetic acid under 1 atm (Gif system). Later, the Gif type oxygenations were performed mostly by using monoiron salts, e.g. FeCl2 4H20 or FeCI,i 6H20. Barton et al reported a number of experiments for application of this system to the more complicated compounds such as steroids " and for clarification of mechanism, specially participation of the radical and nonradical processes. Intermediate formation of Fe -... 

Thermal ST occurs in the trinuclear iron(II) complex [Fe3(iptrz)6(H20)6](Trifl)6 (with iptrz = 4-isopropyl-1,2,4-triazole and Trifl = trifluoromethanesulfonate) only at the... 

A multiple-path mechanism has been elaborated for dissociation of the mono- and binuclear tris(hydroxamato)-iron(III) complexes with dihydroxamate ligands in aqueous solution. " Iron removal by edta from mono-, bi-, and trinuclear complexes with model desferrioxamine-related siderophores containing one, two, or three tris-hydroxamate units generally follows first-order kinetics though biphasic kinetics were reported for iron removal from one of the binuclear complexes. The kinetic results were interpreted in terms of discrete intrastrand ferrioxamine-type structures for the di-iron and tri-iron complexes of (288). " Reactivities for dissociation, by dissociative activation mechanisms, of a selection of bidentate and hexadentate hydroxamates have been compared with those of oxinates and salicylates. ... 

In 1993, Murai s group examined the effectiveness of the iron-triad carbonyl complexes Fe(CO)5, Fe2(CO)9 and Fe3(CO)12 as catalysts for the reaction of styrene with triethylsilane [47]. Whereas Fe(CO)5 showed no catalytic activity, Fe2(CO)9 and Fe3(CO)12 formed selectively P-silylstyrene 57a and ethylbenzene 58. Interestingly, Fe3(CO)12 is the catalyst that exhibited the highest selectivity. This trinuclear iron carbonyl catalyst was also successfully applied in the reaction of different para-substituted styrenes with Et3SiH giving only the (E)-P-triethylstyrenes in 66-70% yield (Scheme 4.23). 

Scheme 78. Trinuclear iron derivative of an alkoxy(l-alkynyl)carbene complex.

Doubly bridged trinuclear clusters may be oxidized or reduced, but the stability of the one-electron product depends on the identity of the bridging group and on the terminal ligands bonded to the metals. The iron complex [Fe3(CO)2(/u-S)(/Li-SR)Cp3], the structure of which has not been fully defined, oxidizes reversibly in two one-electron steps. The monocation was synthesized by iodine oxidation of the neutral species but apparently decomposes to [ Fe(CO)( i-SR)Cp 2] (Section III,E) 148). 

Scheme 7-11 shows the molecular assemblies of a few dinuclear and trinuclear iron(ii) clathrochelate complexes linked to a ferrocenylboronic or a l,l -ferrocenyl-diboronic fragment, which have been recently prepared [82]. 

According to the X-ray crystallographic analysis, 30 is present in the crystal as a neutral, trinuclear, iron chelate complex (Figure 19, right 3D-4). The core of... 

Scheme 3 Formation and schematic representation of /t3-oxo-centered mixed-valent iron complex [Fe30L 3] 30 and octanuclear bicapped bis[trinuclear- <3-oxo-centered) zinc complex [Zn802L (i] 31.

The spectra of five trinuclear iron(III) carboxylate complexes of the type [Fe3(RC02)6(OH)2]X.xH20 are consistent with high-spin iron(III) in a dis-... 

In contrast to iron and manganese, the number of trinuclear cobalt complexes is comparatively small. The reaction of [Co2(CO)s] with 2-propane thiolate or with C3H7SSC3H7 in methanol under solvothermal conditions afforded the electroneutral complex (Co3(SC3H7)s(CO)4], which contains a triangle of cobalt atoms. Its structure is shown in Fig. 16. 

Davies SC, Evans DJ et al (2002) Mononuclear, binuclear, trinuclear and tetranuclear iron complexes of the N(CH2CH2S)3 (NS3) ligand with nitrosyl co-ligands. J Chem Soc Dalton Trans 2473-2482... 

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