Iron sandwich complexes

When the iron sandwich complex bears an arene substituent with at least one benzylic hydrogen, the acidity of the latter is enhanced by the 7t-complexation to the 12e fragment FeCp+. The pKa of the conjugate acid of superoxide radical... 

Mixed arene-2,5-dihydro-l,2,5-thiadiborole-iron complexes have been synthesized by a novel route thermally unstable bis(arene)iron sandwich complexes, prepared by cocondensation of iron atoms with arene, react in the temperature range of -100 to -60°C with free Et2C2B2Mc2S to form reactive intermediates that decom-... 

It has been shown that boratabenzenes can provide the framework for a new family of stable, 19-electron iron-sandwich complexes. For example, treatment of (C6Me6)FeCp with MeBBr2 leads to insertion to furnish the corresponding r 6-boratabenzene adduct (Scheme 18).33 The structures, EPR spectra, and reactivity of these boratabenzene complexes are very similar to their well-studied (arene)Fe(cyclopentadienyl) precursors. The unpaired electron resides in an antibonding orbital that is largely metal based. 

Figure 14. Hexaarm star-shaped iron sandwich complexes.

Dabirmanesh, Q. and Roberts, R.M.G., The synthesis of iron sandwich complexes by microwave dielectric heating using a simple solid C02-cooled apparatus in an unmodified commercial microwave Oven, /. Organomet. Chem., 1993, 460, C28. 

An improvement was reported by Pertici s group by applying an iron sandwich complex which is able to cyclotrimerize terminal and internal alkynes in good to excellent yields (Scheme 9.33) [91]. 

Dendritic Cationic Aminoarene Iron-sandwich Complexes... 

Dendritic Cationic Aminoarene Iron-sandwich Complexes Selectively Recognize Chloride and Bromide Anions... 

Fig. 5.10 Iron sandwich complexes, which are structurally related to ferrocene but contain either one or two planar heterocyclic five-membered rings (with the names of the principal investigators and the date of discovery)...

In Figure 6, an iron sandwich complex with f -coordination of the azaborolyl rings is shown. The iron atom is located exactly above and below the centers of the rings, so reaching the ideal 18-electron configuration. 

Bis(l,2-azaborolyl)iron sandwich complexes, like the isoelectronic ferrocene compounds, are thermodynamically very stable, but, owing to the presence of the boron and nitrogen atoms, they are in any case sensitive to acids and bases. 

Scheme 11.14 Synthesis of 24-iron-sandwich complexes starting from durene.

MW-mediated synthesis of [(77-arene)(CO)3Mn][PF6] salts was also reported, and a bis-complexed triphenylphosphine iron sandwich complex was obtained from the AlCk-catalyzed ligand-exchange reaction between... 

The sandwiched complexes discussed here show that by thermodynamically and kinetically stabilizing intermediate iron oxidation states such as Fe(II), low-oxidation states such as Fe(I) and even Fe(0) become accessible and find useful applications. Conversely, Fe(III) and even Fe(IV) state may also be accessible. The story of iron sandwiched complexes continues with a discussion of the classical ferrocene and congeners in Sect. 17.3.1. 

Dihydro-lH-l,2-azaboroles derive from cyclopentadiene by the isoelectronic replacement of a C=C group by a BN moiety ". The neutral rings react in xs boiling Fe(CO)j without any other solvent to form red-brown iron-dihydro-1,2-azaborolyldi-carbonyl dimers as their cis and transisomers in 56% yield, or with CojfCOg in petroleum ether at 60-80°C to the half-sandwich complex (dihydro-1,2-azaborolyl)Co(CO)2 (40%). The CO group can easily be substituted by olefins ... 

Ferrocene and Half Sandwich Complexes as Catalysts with Iron Participation... 

Catalysis by Iron in Half Sandwich Complexes 2.1 Fe(O)- and Fe(I)-Catalysts... 

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