Transition metal complexes ferrocenyl

Transition Metal Complexes with Ferrocenyl and l,l -Ferrocenediyl Ligands... 

Fig. 5-10. Transition metal complexes containing one a-ferrocenyl ligand.

It is interesting to note that an increasing number of ring-substituted ferrocenyl ligands are being used in transition metal complexes. The substituents may simply reduce the electron-donating power of the electron-rich a-ferrocenyl unit, as in T-chloro- [199, 200], 2-chloro- [183], and 2,T-dichloro- [190] ferrocenyl compounds (Scheme 5-27). 

It is surprising that transition metal complexes containing ferrocenyl thio-late ligands (FcS) have not been studied in detail so far. The only examples are gold complexes such as (Fc-S)Au(PPh3) [86], [(FcS)Au2(PPh3)2](BF4) [86, 183], [(Ph3PAu-S)fc-S-]2 (Scheme 5-18) [90], and [(FcS)Au(nBu)2]3 [86],... 

Scheme5-39. Ferrocenyl thiolate and l,l -ferrocenylene dithiolate derivatives of half-sandwich transition metal complexes.

Chloro(methoxy)- and chloro(phenoxy)carbenes, which are generated from the diazirine precursors, behave as ambiphiles in additions to alkenes, exhibiting high reactivities toward both electron-poor and electron-rich olefins. Methoxy(phenyl)- and ferrocenyl(methoxy)methylenes have been transferred in a stereospecific manner from transition metal complexes of these species to electron-deficient alkenes. Irradiation of benzocyclobutanedione with UV light induces a rearrangement of the cyclic a-diketone to 17, which has been trapped by alkenes in good yields " . Thermolysis of 18 gives rise to nucleophilic dimethoxycarbene, which has been intercepted by electron-deficient olefins or by styrene derivatives. 

Elwahy AHM, Abbas AA, Kassab RM (2002) Unexpected synthesis of novel condensed heteromacrocycles. S5mthesis 2 260-264. doi 10.1055/s-2002-19809 Ertas I, Gok Y, Kantekin H, Ocak U (2007) The synthesis and characterization of (E, )-dioxime and its transition metal complexes containing 12-membered macrocycles linked to ferrocenyl-methyl groups. J Coord Chem 60(23) 2509-2517. doi 10.1080/... 

Hayashi T, Hayashizaki K, Kiyoi T, Ito Y. Asymmetric synthesis catalyzed by chiral ferrocenylphosphine-transition-metal complexes. 6. Practical asymmetric synthesis of 1,1 -binaphthyls via asymmetric cross-coupling with a chiral [(alkoxyalkyl)ferrocenyl] monophosphine/nickel catalyst. J. Am. Chem. Soc. 1988 110(24) 8153-8156. 

Other spectroscopic techniques that have been used in the study of dppf complexes are XPS, UPS [43] and UV/VIS spectroscopy. XPS provides useful complementary information on the differentiation of pendant and coordinated phosphines [42,80]. Caution needs to be exercised, however, as P(2p) core binding energy is not very sensitive towards changes in the ligand coordination mode or the oxidation state of the metal [42]. The electronic absorption spectra of dppf and MCl2(dppf-P, P ) complexes (M = Co, Ni, Pd, Pt, Zn, Cd, Hg) exhibit an easily detected band at 405—465 nm, attributed to a transition in the ferrocenyl moiety [43]. The presence of any iron-to-metal bonding is usually indicated by an intense ct - a transition [21], as evident in the electronic spectrum of [Pd(dppf-P,P )(PPh3)][BF4]2, 3 [40]. 

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. 

Half-sandwich complexes of the group 6 and 8 transition metals carrying one a-ferrocenyl ligand are presented in Table 5-3. 

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