Cyclooctatetraene-iron carbonyl complexes

Diiron enneacarbonyl, synthesis 46 Triiron dodecacarbonyl, synthesis 46 Tricarbonyl(cyclooctatetraene)iron, synthesis 47 Iron carbonyl complexes of triphenylphosphine, triphenyl-arsine, and triphenylstibine, synthesis 48 cis-Dinitrobis(ethylenediamine)cobalt(III) nitrite and nitrate, synthesis 60... 

Cyclooctatetraene (COT) iron carbonyl complexes and ruthenium carbonyl complexes (Table 5) have raised a good deal of interest as flux-ional molecules which display temperature dependent NMR spectra e.g. COT-Fe(CO)3 shows only one sharp peak at room temperature, but a pattern conceivable with... 

Although a number of iron carbonyl complexes have been prepared with cyclic conjugated polyene systems such as cyclooctatetraene, linear conjugated polyene systems have been studied only up to 1,3,5-hexatriene,... 

B. Dickens, and W. N. Lipscomb, Molecular and Valence Structures of Complexes of Cyclooctatetraene with Iron Carbonyl, J. Chem. Phys. 37, 2084-2093 (1962). 

Cyclooctatetraene, as a ligand in transition-metal complexes (especially iron carbonyls), reacts with electrophiles to form t -bicylo[5.1. Ojoctadienyl complexes such as 7. Reviews concerning early examples of this reaction type are available. 

A third product of the iron carbonyl-cyclooctatriene reaction is a red complex of formula CgHioFe2(CO)g, which was initially formulated as C9Hi2Fe2(CO)e (61). This is derived from the 1,3,5-isomer and probably has a bis(7r-allyl) structure like the corresponding complexes with cyclo-heptatriene (Section II, A) and cyclooctatetraene (Section III, B) (46, 90). 

Reactions of diene-Fe(CO)3 complexes with other molecules capable of forming ligands with metals in low oxidation states can result in either displacement of the diene ligand or of one of the carbonyl groups. For example, the Fe(CO)3 complexes of with triphenylphosphine with liberation of the hydrocarbon ligands 34,19). Cyclooctatetraene-iron tricarbonyl gives cyclooctatetraene when treated with P 3 but with As 3 or Sb 3 the... 

A number of metal carbonyls and cyanides, particularly those of nickel and iron, form 7r-complexes with alkynes. These systems behave cat-alytically in the carbonylation of acetylene and in the formation of trimers (benzene) and tetramers (cyclooctatetraene). 

The use of NHC-iron species in a catalytic organometallic transformation leading to the formation of metal-metal bonds was brought to light in 2009 by Lavallo and Grubbs. When the non-carbonyl Fe" complex [Fe(cot)2] (cot = cyclooctatetraene) was treated with SIMes, a stoichiometric reaction ensued, and a high yield of crystalline compound 1 was obtained (Equation (7.1)). Use of bulkier SIPr resulted in a difibrent reaction path, which afforded the tri-iron cluster [Fc3(cot)3] (2) in a catalytic fashion (Equation (7.2)). 

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