Iron cyclopentadienyl containing

Enantiopure 2-formyl-3,4-dimethylphosphaferrocene has been prepared by column chromatography of the aminals from reaction with (i ),(i )-l,2-di(iV-methylamino)cyclohexane. Chiral pinene-fused cyclopentadienyl-containing phosphaferrocenes have also been prepared directly from the iron tricarbonyl complex PCp Q CO)2 z /-butyl-phosphole, where PCp = pinene-fused cyclopentadiene. A crystal structure of the product phosphaferrocene is shown as... 

Ferrocene Figure 2-47) provides a prime ex.ample of multi-haptic bonds, i.e, a situation where the electrons that coordinate the cyclopentadienyl rings with the iron atom arc contained in molecular orbitals delocalised over the iron atom and the 10 carbon atoms of the cyclopentadienyl rings [82. ... 

Kiindig EP, Saudan CM, Viton F (2001) Chiral cyclopentadienyl-iron and -ruthenium Lewis acids containing the electron-poor BIPHOP-F ligand a comparison as catalysts in an asymmetric Diels-Alder reaction. Adv Synth Catal 343 51-56... 

Another complex involving the formation of a cyclopentadienyl unit is obtained from the interaction of ethyl or propyl acetylene with Fe3(CO)i2 117). The products contain the complexes Fe3(CO)7(HC2R)4 (R = Et, re-Pr), and the crystal structure of the ethyl derivative indicates the presence of the substituted 1,2,3-triethylcyclopentadienyl group bonded to one iron center with an ethylallyl group cr- and n-bonded to the three metal centers. The formation of adducts of this type must involve the fission of the C=C bond of the acetylene. 

The classic (if not classical) metal sandwich species bis(cyclopentadienyl)iron has the formula [(CH)5]2Fe (CpaFe) and the semisystematic name ferrocene, and so the related magnesium-containing species [(CHfsJaMg (CpaMg) is often accompanied by the name magnesocene. We commence our discussion with this species. 

Similar results have been obtained by Ismailov et al. (240) in Y-type zeolites containing iron impurities (Section IV,C,3). The formation of 02 on the ferrocene/porous Vycor glass system has been observed by Vanderspurt et al. (120) with a g tensor of 2.0300, 2.0100, 2.0020 and a superhyperfine sextet centered on each g component. These results were interpreted in terms of 02 adsorbed on the cyclopentadienyl ring of ferrocene and, assuming an ionic model, the g2Z value of 2.0300 is broadly consistent with a +3 charge at the adsorption site. 

Such units, together with methyl derivatives of ferrocene and cyclopentadienyl (r 6-arene)-iron(II), [FeCp(r 6-arene)]+, have been extensively used as dendrimer peripheral units, but examples of dendrimers containing metallocene residues both as a core and as terminal units and as a core are also reported.5a,b 17... 

Heterometal alkoxide precursors, for ceramics, 12, 60-61 Heterometal chalcogenides, synthesis, 12, 62 Heterometal cubanes, as metal-organic precursor, 12, 39 Heterometallic alkenes, with platinum, 8, 639 Heterometallic alkynes, with platinum, models, 8, 650 Heterometallic clusters as heterogeneous catalyst precursors, 12, 767 in homogeneous catalysis, 12, 761 with Ni—M and Ni-C cr-bonded complexes, 8, 115 Heterometallic complexes with arene chromium carbonyls, 5, 259 bridged chromium isonitriles, 5, 274 with cyclopentadienyl hydride niobium moieties, 5, 72 with ruthenium—osmium, overview, 6, 1045—1116 with tungsten carbonyls, 5, 702 Heterometallic dimers, palladium complexes, 8, 210 Heterometallic iron-containing compounds cluster compounds, 6, 331 dinuclear compounds, 6, 319 overview, 6, 319-352... 

As far as the metal center is concerned, the stereospecificity of the S02 insertion was demonstrated with diastereoisomeric Fe compounds that contain chiral centers on the metal and either in the substituted cyclopentadienyl ring21) or in the alkyl side-chain21,22). The stereochemistry of the S02 insertion with respect to the metal atom was studied with the optically active iron compounds 8a and 8b23 Liquid S02 inserts into the Fe—C bond of 8a and 8b with retention of configuration23) [Eq. (7)]. The similarity in the chiroptical properties of 8a and 9a as well as 8b and 9b was used for the assignment of relative configurations23). 

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