Iron-toluene complex

FeCls reacts with Li[C(SiMe3)3], in toluene at 55-60 °C, to give the red violet iron(II) complex [Fe C(SiMc3)3 2]. This is monomeric, with linear C—Fe—C and an Fe—C bond distance of 2.05... 

Cyclobutadiene-iron tricarbonyl is a pale, yellow solid, m.p. 26°C., which exhibits a single, sharp NMR absorption at r 6.09. In common with other diene-iron tricarbonyl complexes, the material displays appreciable thermal stability, as well as a pronounced resistance to further replacement of the CO ligands several hours treatment with triphenylphosphine in refluxing toluene leaves the complex unaffected. 

The iron vapor-toluene reaction has evoked interest because of the lability of the proposed bis(arene)iron complex to ligand subsitu-tion and to loss of both toluene molecules to free the metal atom. In the latter case the toluene molecules may be usefully regarded as metal atom carriers which can be used to direct the latent reactivity of the atom in subsequent solution phase chemistry. In this way the metal atom experiment can benefit from the convenience and additional versatility afforded by bench-top chemical manipulations. These results are relevant to a reported preparation of a dehydroxy-lated silica-supported Fischer-Tropsch catalyst from a static reactor codeposition of Fe and toluene.(46) In the liquid phase, iron atoms "bottled" in this way have also been utilized in an exceedingly mild method for making minute catalytically active superparamagnetic clusters on the surface and within the cavities of a dehydrated sodium zeolite Y.(38) Using the rotary reactor, preformed solutions of solvated iron atoms (as the toluene complex) are cannulated below their decomposition temperature out of the flask to a cold slurry of the support in toluene. Diffusion of intact... 

The degree of steric encumbrance is illustrated by the rates of metallation and oxidation of the various isomers. The adjacent cis-linked isomer 248c has one face unhindered and is easily metallated. In contrast the other isomers, where both faces are hindered, undergo iron insertion reluctantly. While not preventing ligation of nitrogenous bases or diatomic molecules, the chains do inhibit irreversible oxidation at room temperature. For the four-coordinate iron(II) cross trans-linked isomer 248a the t a for oxidation to the hematin derivative Fe (P)OH is 1.5-10.5 minutes compared to 7-54 seconds for oxidation of the less hindered isomers to the p-oxo complex. Similarly, in toluene at 25 °C under O2 (1 atm), t]/2 for oxidation of the six-coordinate iron(II) complex is 11-25 min for the cross trans-linked isomer compared to 1.5-12 min for the other two isomers ... 

The state of aggregation of the solute may depend upon the solvent and so lead to solvent dependent spectral changes. In solutions of Fe ions there has been uncertainty whether the species present were monomeric, dimeric or larger aggregates. In strongly co-ordinating solvents iron(III) complexes seem to be monomeric, except in the presence of alkali. Dimeiisation in such poorly co-ordinating solvents as ether, benzene, or toluene may result from the presence of traces of moisture. Scrupulously dry solutions of ferric chloride and TV-substituted salicylaldimine complexes of iron(III) in these and similar solvents are monomeric, but traces of moisture cause the latter at least to dimerise. ... 

Carbon monoxide hydrogenation catalysts have been obtained by thermal decomposition of intrazeolite iron bis(toluene) complexes [258],... 

Figure 1. SEM images of a typical nascent PE film produced by ethylene polymerization over flat silica with anchored bis(imino)pyridyl iron(II) complex. Polymerization occurred at room temperature in toluene with 2 bar ethylene pressure for 24 h. The polymer film is broken into islands, which are connected by stress fibers, (a) and (b) Top view images, (c) side view of the polymer film.

Consecutive substitution of all chlorine atoms in cyanuric chloride 20 with diethylamine, dipyridylamine, and dia2a-18-crown-6 resulted in a new ligand 45, which forms spin-cross-over iron(ll) complexes. Due to the low nucleo-phdicity of dipyridylamine, substitution of the second chloride proceeds selectively even after 3 days refluxing in acetonitrile. The third substitution in the reaction of 46 with the diazacrown can be achieved only after 4 days refluxing in acetonitrile/toluene mixture to give 45 in 17% overall yield (13DT16494). 

Iron carbonyl fragments have been incorporated into many heterometallic borane and carborane compounds. Those compounds are covered in Chapter 3.05 and will not be discussed here. Simple boryl adducts have been reported from the reaction of Na2Fe(CO)4 and ClBCat" (Cat = catecholate or a Bu-substituted derivative. Equation (8)). The same products can be obtained upon irradiating Fe(CO)s and Cat B-BCat" in toluene at 0°C. Reaction of the diboryl 6 with 1 equiv. of lithium bis(trimethylsilyl)amide in toluene solvent leads to removal of one boryl unit and the formation of an anionic iron boryl complex (Equation (9)). The anionic species can also be obtained by stoichiometric addition of the ClBCat complex to Na2Fe(CO)4. Reaction of [Fe(CO)4 B(3,5-/-Bu2-Cat) ] with ClSnMes gives the stannylated derivative Fe(CO)4 B(3,5-/-Bu2-Cat) (SnMe3). 

Iron carbonyl complexes containing tin(ll) ligands could also be obtained starting from arene iron complexes by displacement of the arene (Equations (49) and (50))4 Reactions of (arene)Fe(SnR2)(ethene) or bis bis(2- /t-butyl-4,5,6-trimethylphenyl) Sn Fe( -toluene) with carbon monoxide led to the substitution of the ethene and toluene ligands (Equation (49))4 The complex bis bis(2- /ir-butyl-4,5,6-trimethylphenyl) Sn Fe( j -toluene) was synthesized and reacted with 1 atm of carbon monoxide (Equation (50)). Attempts to synthesize the product in which only the toluene is substituted were unsuccessful. 

New 77 -iron tricarbonyl complexes of 2,3-dihydropyrrole were formed by the thermolysis of iron 7V-methyl-7V-allylaminocarbene complexes in toluene at 100 °G. Attempts to prepare 19 by direct complexation of independently prepared l-methyl-2-phenyl-4,5-dihydropyrrole with Fe(GO)s or Fe2(GO)9 were unsuccessful. 

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