Iron atom, sandwiched

O Ferrocene is the common name given to a unique compound that consists of one iron atom sandwiched between two rings containing hydrogen and carbon. This orange, crystalline solid is added to fuel oil to improve combustion efficiency and eliminate smoke. As well, it is used as an industrial catalyst and a high-temperature lubricant. 

Reaction of iron atoms with cycloheptatriene to form [Fe( r) -C7H7)-(t7 -C7H9)] was confirmed by another group 15) these workers determined the crystal structure of the species, demonstrating a sandwich structure with the open faces of the two 7j -systems skewed to each other. The temperature-dependent NMR spectrum of this species (16) indicated two types of fiuxional behavior in solution. Evidence for a 1,-2-shift mechanism of the l-5-i7-cycloheptatrienyl moiety in the structure shown. 

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-... 

The strueture of the di-iron eomplex [Fe2(p, t, t -BH6)(PEt3)g] (127) contains a boron atom in the oetahedral environment of 6 equiv. hydrides capped on the opposite faeets by two iron atoms.Thus, neglecting the second iron center, the geometry is very reminiseent of the complex 125. DFT calculations supplemented by an AIM study eonfirmed the presence of six H-B interactions and direct Fe B bonds. The strueture was eonsidered as containing a boron trication B " sandwiched between two anions [Fe(H)3(PEt3)3] . 

Ferrocene has a structure in which the iron atoms is sandwiched between two C5H5 organic rings. It has... 

Terminology useful for sandwich compounds includes "bread" for the outer layers (cyclopentadienyl rings in formula (29) and "meat" for the "sandwiched atom or group of atoms [the iron atom in (29)]. By the use of this sandwich nomenclature, the decision as to whether Figure 8 or 10 is the chemically correct one has been sidestepped. Furthermore, there is a straight-forward expansion of such a nomenclature to both "open" (also called "half ) and also to "multiple" (also called "Dagwood") sandwiches ... 

In XXXIII iron is sandwiched between the phospholyl and phospholium rings. The role of the benzoyl group is to hinder attack of the second phosphorus atom. 

At low temperature and pressure, a gas phase reaction can occur between iron atoms and toluene. The product, a rather unstable sandwich compound, reacts with ethylene to give compound X. Compound X decomposes at room temperature to liberate ethylene at —20° it reacts with P(OCH3)3 to give Fe(toluene)[P(OCH3)3]2. Suggest a structure for compound X. (Reference U. Zenneck and W. Frank, Angew. Chem., Int. Ed., 1986,25, 831.)... 

The solid (m.p. 173 ) is remarkably stable, and is unaffected by NaOH and HCl even at the boiling point. The complex is diamagnetic, has zero dipole moment, and all its CH bonds are alike It has a sandwich structure with the iron atom lying between two pentagons (Wilkinson, Rosenblum,... 

Compound 48 and the ferrocenyl-gold""" and ruthenocenyl-gold " compounds 49 provide interesting examples of a hypercarbon atom that is not only part of an aromatic cyclopentadienyl ring system, in which it is bonded to two other carbon atoms, but also bonds simultaneously to the sandwiched iron atom and (by a 3c-2e bond) to the two coinage atoms. The related dication 50 has also been isolated. " ... 

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. 

The B9Hio 0(C2Hj)2 adduct reacts with acetylene to form ° nido-5,6-C2BgHi2-Reaction of B5H9 with alkynes in the presence of thermally generated iron atoms yields as the major product the ferracarborane sandwich complex, ... 

To achieve electrical conductivity the metal atoms have to be in different oxidations states [90]. Since the discovery of the Cruetz-Taube complex 181 [164] the delocalization of electrons in various sandwich complexes has been examined [165, 166]. As was shown, the unpaired electron in the bis(fulvalene)bis(iron) ion 182 is completely delocalized and regarded as an ion of class III the two iron atoms exist in a mixed valence state (Fig 47) [166,167]. The ion 183 belongs to class II, because a considerable energy barrier in the interaction of the two metal centers was established (Fig. 47) [166,167], The ion 184 is not suitable for the design of a polymer, because the unpaired electron is completely localized at one of the chromium atoms, so that one of them carries a positive charge, while the other remains uncharged (Fig. 47) [166, 168]. 

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