Iron cluster groups

Figure 2. Logarithm of the scaled reactivities of iron clusters with hydrogen/deuterium from the Exxon (circles), Argonne (triangles and diamonds), and Rice (crosses) groups. The data are normalized to Feio °f the Argonne groups.

As [Fe(CO)s] readily reacts with alumina hydroxyl groups to provide the [HFe3(CO)ii] trinuclear immobilized iron cluster (Figure 9.5) with simultaneous... 

It is now clear that in addition to their widespread involvement in electron transfer pathways, iron-sulfur clusters function as catalytic centers in a wide variety of enzymes. The first example of such an enzyme is aconitase. It was at first thought that the role of the iron-sulfur group was regulatory, but it is now clear that in this enzyme the iron-sulfur group is part of the catalytic site. One of the iron atoms can coordinate water or hydroxyl and plays a key role in the isomerization catalyzed by the enzyme (Emptage et al., 1983). 

The reaction of [Fe3(CO)n]2- with Ph3PbCl in THF produced a unique iron cluster 115, which contains triangular Fe3 core and a terminal Ph3Pb group bonded to one of the Fe atoms, forming a linear Fe—Fe—Pb arrangement499. 

The iron cluster [Fe4S4(SPh)4] catalyzes the reduction of nitroarenes to arylamines. " A less hydridic nucleophile [HFe(CO)4] has also found application as a selective reducing agent for nitroarenes." Although [HFe(CO)4]"] is known to reduce aldehydes, ketones and acid halides," in THF solvent with tri-fluoroacetic acid, it selectively reduces nitrobenzenes to anilines in the presence of aldehyde and acid halide groups. 

The iron cluster [ (Tn5-C5H5)Fe( JL3-CO) 4], catalyzes the selective hydrogenation of alkynes to alkenes at 100-130 C and 6.8-68 atm of H2. Internal alkynes are slowly reduced to ds-alkenes, but nitro groups attached to aromatic rings and terminal carbon-carbon double bonds are also hydrogenated. ... 

Reaction of Fe(CO)5 with cyclo-(AsMe)5 yielded the dimer [Fe(CO)3]2[p, j -catena (MeAs)4] with a four-membered AsMe chain . The trinuclear iron cluster [Fe(CO)3]3[SbCH(SiMe3)2]2 contains an antimony ligand. The Sb atoms are bound to each other, secondly to the organo group and thirdly coordinated to three Fe atoms each . p3-SbR ligands are rare. However, recently a species of the type [HFe3(CO)9 (p3-SbBu )] [PPN] has been reported . 

Reactions of the iron cluster anion 40 with phenylarsenic dichloride" and dimethylar-senic chloride" , respectively, lead to 41 and 42. In the first case, one edge of the Fcj triangle opens and the PhAs group bonds to each of the three iron atoms (As—Fe 2.275,2.276,2.359, As—C 1.92 A), while in the second, the Me2As group inserts into one of the Fe—Fe bonds (As—Fe 2.382,2.373, As—C 1.983,1.968 A). 

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