Ferrocenyl complexes

An iinportanl advance in this synthesis of allylsilanes involved the use of optically active palladium ferrocenyl complexes as catalysts to provide optically active allylsilanes with good enantiomeric excesses being obtained for (/. (-allylsilanes and less good enantiomeric excesses for (Z)-allylsilanes26,27. 

The asymmetric hydrogenation of C=N (Eqn. (23)), in contrast with C=0 and C=C bonds, is much less developed. Hexahydrowoquinoline was used as its phosphoric acid salt. Iridium-ferrocenyl complexes were found to be sati.sfactory. After optimisiation, Meyer et al. (1997) were able to realize an enantioselectivity of 89% ee. 

Cp(PMe3)2RuC=CH and the corresponding vinyl compound react with 1 to give the expected hydrozirconated complexes [225, 226]. Hydrozirconation reactions were also observed with the vinyl and acetylenic ferrocenyl complexes [227]. In marked contrast, the iron complex Cp (dppe)Fe-C=CH reacts anomalously with Schwartz s reagent to form acetylide Cj-bridged heterodinuclear complexes (Scheme 8-31) [228]. 

P)GeFc2 compounds, suggesting delocalization of electron density from the porphyrin to the ferrocenyl group. The conclusion is that the stability of Ge—C bonds is higher in the ferrocenyl complexes than in the alkyl complexes165. 

An extension of this methodology, by hexafunctionalization of the arene group in 13 using ferrocenylbutyl iodide 14 under basic conditions, gave the hexafluoro-phosphate salt of the heptanuclear Fe(Il) complex cation 15 in 65% yield. Photolysis of 15, under similar conditions which converted 8 into 9, led to isolation of the neutral ferrocenyl complex 16 by selective decomplexation of the central... 

Table VII contains data for a series of ferrocenyl complexes for which lj. (3 values only are extant in the absence of reported dipole moments, only an internal comparison is possible. The results are resonance enhanced and, as the applicability of the two-level correction is questionable (see...

Molecular NLO Results for Ferrocenyl Complexes for Which /x -j8 Values Have Been Reported"... 

The standard method of synthesis involves the reaction of suitable transition metal halides with Fc-Li [49, 113, 171 — 180, 189, 190], although HgFcj has also been used as ferrocenyl transfer reagent [181 — 183]. A different approach to ferrocenyl complexes proceeds via thermal or photo-induced decarbonylation of the corresponding ferrocenoyl compounds [178,184]. All three routes have been applied to prepare the half-sandwich/sandwich complex CpFe(CO)2-Fc, which contains two different iron centers (Scheme 5-24). It is surprising that Fc-SnMej has rarely been used [185] for ferrocenyl transfer. 

Scheme 5-26. Half-sandwich cyclopentadienyl tungsten-ferrocenyl complexes [177].

Chemical or electrochemical oxidation of a-ferrocenyl complexes generally leads to the corresponding a-ferrocenium cations in a reversible electron transfer process. Oxidation of Mn(CO)s-Fc by iodine produces a black salt [Mn(CO)5-Fc ]2(l ),... 

Table 7-2. Half-wave potentials (m. SCE) for the sequential oxidation of the chromium-ferrocenyl complexes (> -C5H5)Fe[( C5H4- R (> -C6H5)Cr(CO)3] shown in Scheme 7-1...

Scheme 7-10 shows a series of ketophosphine-rhenium-ferrocenyl complexes of known redox behavior. 

Figure 7-27 illustrates the redox fingerprints of all the ruthenium-ferrocenyl complexes in acetonitrile solution [9, 93]. 

A somewhat related family of cobalt-ferrocenyl complexes is shown in Scheme 7-18 [117]. 

Another cobalt-ferrocenyl complex, whose electrochemistry has been studied, is shown in Scheme 7-20 [119]. 

The open or locked polyamine-ferrocenyl complexes of nickel(ii), illustrated in Scheme 7-29, have been prepared recently [145 — 147]. 

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