Addition of Disiliranes

When endohedral metallofullerenes which are fullerenes with metal(s) inside the hollow spherical cage are employed, the addition of disilirane to La Cg2 and Gd Cg2 (Eq. 19) occurs in both thermal and photochemical ways [268, 269]. 

Akasaka T, Nagase S, Kobayashi K, Suzuki T K, Kikuohi K, Aohiba Y, Yamamato K, Funasaka FI and Takahashi T 1995 Synthesis of the first adduots of the dimetallofullerene La2 Cgg and Se2 Cg by addition of a disilirane Angew. Chem. Int. Edn. Engl. 34 2139... 

The photochemical addition of some cyclic oligosilanes to Ceo has also been found interesting. Scheme 8.8 shows some examples of such a transformation. Irradiation (X > 300 nm) of a toluene solution of disilirane 36 with Ceo afforded the fullerene derivative 37 in a 82% yield [37]. The reaction mechanism is still unknown. When toluene is replaced by benzonitrile the bis-silylated product of the solvent was obtained in good yields. In these experiments a photoinduced electron transfer between 36 and Ceo is demonstrated, indicating the role of Ceo as sensitizer [38]. The photoinduced reactions of disilirane 36 with higher fullerenes such as C70, Cv8(C2v)and CuiDi) have also been reported... 

Irradiation of a toluene solution of l,l,2,2-tetramesityl-l,2-disilirane 116 resulted in the formation of the [6,6]-closed l,l,3,3-tetramesityl-l,3-disilolane 117 with Cs symmetry (Scheme 49) [274a], The reaction is surpressed by addition of DABCO and 1,2,4,5-tetramethoxybenzene and completely inhibited by addition of rubrene. As rubrene is known to be an effective triplet quencher, there is... 

In this brief overview of C70-addition patterns, it may also be mentioned that photochemical addition of l,l,2,2-tetramesityl-l,2-disilirane afforded a C2-symmetric adduct for which the unusual addition across the equatorial,... 

Akasaka, T., Nagase, S., Kobayashi, K. et al. (1995) Synthesis of the first adducts of the dimetallofullerenes La2C80 and SC2C84 by addition of a disilirane. Angewandte Chemie International Edition, 34, 2139-2141. 

Stable disilacyclopropanes (disiliranes) are obtainable by means of the addition of dimesitylsilylene to l,l-dimesityl-3,3-bis(TMS)-l-silapropadiene (320a) and 1,1-dimesityl-3-phenyl-3-TMS-l-silapropadiene (320b), respectively, to yield the corresponding l,l,2,2-tetramesityl-3-[bis(TMS)methylene]-(321a) and l,l,2,2-tetramesityl-3-[phenyl-(TMS)-methylene]l,2-disilacyclopropane (-disilirane) (321b) (equation 146)170. 

Addition to the fourth and least curved 6-6 bond C(20)-C(21) lying on the equator of the Cyg spheroid (Fig. 6) seems unlikely, although it was suggested for the product of the photochemically induced l,l,2,2-tetramesityl-l,2-disilirane addition [127]. This bond type is completely surrounded by hexagons and can be considered as biphenyl-like, as suggested by the above considerations as well as structural data showing it to be the longest in Cyg [122,126] (Fig. 6). 

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