Iridium fullerenes

With the discovery of Ceo and other fullerenes see Carbon Fullerenes), it was not long before investigations into the possible reactions of fullerenes and iridium complexes were undertaken. Quite a variety of exohedral iridium fullerene compounds have been characterized including complexes of... 

Ir Mossbauer spectra of several iridium fullerene derivatives have been recorded and used in combination with theoretical methods to assess the donor-acceptor properties of the polycarbon molecules." " " ... 

Organometallic compounds, 14 550-551 25 71. See also Organometallics carbides contrasted, 4 648 as initiators, 14 256-257 iridium, 19 649-650 molybdenum(III), 17 27 osmium, 19 642-643 palladium, 19 652 platinum, 19 656-657 reaction with carbonyl groups, 10 505-506 rhodium, 19 645-646 ruthenium, 19 639 sodium in manufacture of, 22 777 titanium(IV), 25 105-120 Organometallic fullerene derivatives,... 

A similar situation is encountered in reactions with transition metal complexes where the fullerenes behave much like large olefins. For example, the addition of Vaska-type iridium complexes, such as Ir(CO)Cl(PR3)2, to fullerenes which has proven to be an effective way of obtaining materials that are suitable for crystallographic studies 88... 

Vaska-type iridium compounds Ir(CO)Cl(PR3)2 bind readily and reversibly to fullerenes via the iridium atom. Flexible, aromatic substituents on both phosphorus atoms then may accommodate interactions with the convex exterior of Ceo- As a result linear fullerene chains precipitate as black crystallites (Figure 5.37). 

The reactivity of Qo comparable to that of electron deficient conjugated olefins is nicely reflected by reactions with transition metal complexes. A variety of single crystal structures and spectroscopic studies show that the complexation of transition metals to the fullerene core proceeds in a dihapto manner or as hydrometalation reactions rather than in rf- or ] -binding mode. This was elegantly demonstrated by the reaction of Cgg with ruthenium complexes (Scheme 8) [144]. A variety of iridium complexes ( ] -Cgo)Ir(CO)Cl(PR R R )2 were synthesized by allowing Cgg to react with different Vaska-type complexes Ir(CO)Cl(PR R R )2 [145]. ] -Complex formation was also observed upon reaction of Cgo with other Ir [146] as well as Rh [147] complexes. Hydro-metallation was obtained with Cp2Zr(H)Cl [140]. 

Chiral functionalization patterns also occur in the iridium complexes [144] CO crystallized from a solution containing the two C70O isomers 1 and 7 (Fig. 5) [102,103]. In both complexes, the transition metal and the epoxy bridge are located not only within the same hemisphere of the fullerene, but they are bound to... 

The X-ray crystal structure of [(C6o) Ir2Cl2(r -COD)2)2]. where the two iridium moieties were found to coordinate to the same six-membered ring of the fullerene species, has been determined . ... 

Yanagisawa, M., Tashiro, K., Yamasaki, M. and Aida, T. Hosting fullerenes by dynamic bond formation with an iridium porphyrin cyclic dimer A chemical friction for rotary guest motions. J. Am. Chem. Soc. 129, 11912-11913, 2007. 

A series of Ceo complexes of the type [Rh(acac)(T 2-C6o)(pyridine)2] have been reported and the X-ray crystal structure with 3,S-dimethylpyridine has been determined. The formation and structural characterisation of the fullerene epoxide complex [Ir(r -C6oO)(CO)Cl(PPh3)2] has been described. The synthesis of [Ir(li2.C6o)(CO)(H)(PPh3)2] has been reported. Multiple additions of Vaska-type iridium complexes to have been shown to result in preferential crystallisation of the "para" double addition products C6o) If(CO)Cl(PR3)2 2l (R = Me, Et). The X-ray crystal structure of [ (112-C84)(CO)Cl(PKi3)2l has been reported . 

Since the publication of GOMG (1995) (Vol 7, Ghapter 3.3.1.1), the coordination chemistry of fullerene and its derivatives has continued to be investigated mainly by Balch and Olmstead. A review summarizing the research in this field has been published in 1998. Iridium has continued to be central in developing this chemistry and several new iridium complexes have been described involving either fullerene or some of its derivatives. 

Dendrimers containing phosphines have been used to prepare the Vaska s-type complexes frans-[Ir(GO)Cl PPh2(G-I) 2] and /ra r-[Ir(CO)CI PPh2(G-2) 2]- These reversibly coordinate fullerenes in PhCl." Fullerene derivatives of iridium hydrides have been described by Usatov ef reaction of both... 

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