Iron carbonyl phosphine derivatives

Bis(phosphine) derivatives of pentacarbonyliron are starting materials for the synthesis of several organometallic iron complexes. " Iron carbonyl phosphine complexes have attracted attention because of their relevance to photochemical catalysis of olefin hydrosilation. Though Fe(CO)3(PR3)2 complexes are used widely in organotransition metal chemistry, an efficient preparation of these compounds has not been reported. Clifford and Mukherjee describe two methods for the synthesis of tricarbonyl-bis(triphenyphosphine)iron(0). They report that direct reaction between Fe3(CO)j2 and triphenylphosphine in THF solvent gives a mixture of Fe(CO)3[P(C6Hs)3]2 (27%) and Fe(CO)4[P(C5H5)3] (34%). The second... 

Bis(phosphine) derivatives of pentacarbonyliron are starting materials for the synthesis of several organometallic iron complexes.Iron carbonyl phosphine complexes have attracted attention because of their relevance to... 

Dodecacarbonyltriiron (Fe3(CO)j2) is an important starting material in preparative iron carbonyl chemistry. Many of its reactions lead to rupture of the iron triangle to give mononuclear iron carbonyl derivatives. Thus the major products from the reactions of Fe3(CO)i2 with tertiary phosphines R3P [e.g., R = C0H5... 

Irradiation of (methyl acrylate)iron tetracarbonyl in the presence of excess methyl acrylate at 20° forms a ferracyclopentane product. Thermal reaction of the metallocyclopentane with carbon monoxide or triphenyl-phosphine affords a cyclopentanone derivative (Grevels et al., 1974). Similar ferracyclopentane complexes may be involved as intermediates in the well-known cyclopentanone formation from iron carbonyls and strained olefins (for example, Grandjean et al., 1974 Mantzaris and Weissberger, 1974). 

The substituted iron carbonyls Fe(CO)4PPh3 and Fe(CO)3(PPh3)2 have also been examined as photocatalysts for hydrosilation however, the qualitative reactivity features were found to be similar to those of Fe(CO)s [74]. In addition the polymer anchored derivatives Fe(CO)4(PPh2-poly) and Fe(CO)3(PPh2-poly)2 (where PPh2-poly is the polystyrene bound diphenyl phosphine) proved to be effective photocatalysts for lx)th hydrosilation and hydrogenation [74]. Photocatalysis of alkene hydrosilation is also effected by metal carbonyl clusters [61]. 

The tetrakis(trimethylphosphine) derivative Fe4C(CO)9(PMe3)4 has been characterized by H, 3 P, and, 3C NMR spectroscopy, and on the basis of the presence of two equally populated phosphine sites is assigned the symmetric structure, each iron atom bearing one phosphine ligand and two carbonyls (12). This was confirmed by X-ray diffraction (13). 

The most studied reaction involves the replacement of carbonyl groups by tertiary phosphines. This proceeds most readily in the case of cobalt derivatives, manganese compounds must usually be heated, and iron compounds require irradiation (except in the case of entry 13). 

Wilkinson (9) isolated the tetrakis(trihalogenophosphine)nickel compounds Ni(PX3)4 (X= F, Cl, Br), and Behrens (10) isolated the triphenylphosphine complex Ni[P(C6H5)3]4 via [Ni(CN)4]4. With iron pentacarbonyl, isonitriles and phosphines yield (11) mono- and disubstituted derivatives, Fe(CO)4L and Fe(CO)3L2, respectively, the latter being the well-known cyclization catalyst of Reppe (7). With the same ligands, carbonyls of the chromium group afforded pentacarbonyl derivatives M(CO)5L. However,... 

The olefin complexes of iron, nickel, rhodium, and iridium described in this chapter have found broad application in the synthesis of phosphine, phosphite, and carbonyl derivatives of these metals. In Chapter Two, the synthesis of another labile olefin complex, (ethylene)bis(tricyclohexylphosphine)nickel, is described as an initial step in synthesis of a complex of dinitrogen. 

The separation of the complex mixtures of selenido-carbonyl iron clusters, derived from the synthetic routes described above, can also be accomplished by high-performance liquid chromatography (HPLC). This technique (eventually coupled with mass-spectrometric detection ) is particularly convenient for the separation of organometallic species, owing to its superior speed and efficiency when compared with traditional column and thin layer chromatography. The order of elution of the iron clusters on silica is strongly dependent on the degree of phosphine substitution and on the cluster framework, which, in the first place, determines the polarity of the molecule. ... 

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