"Front Matter". In: Organosilanes in Radical Chemistry - Index of

Silylated Fullerenes 201
electron transfer mechanism (Reactions 8.17 and 8.18) [36]. The electron
transfer has been revealed by following the decay of 3 C 60 or, alternatively, the
rise of the radical anion of C60 and the radical cation of polysilane, which both
absorb in the near-IR region. The kET for the latter reaction is
2:0 10 8 M 1 s 1 in benzene–acetonitrile (2:1) and depends on the polarity of
the medium.
3 C*60
C 60
hν (532 nm)
3C* 60
(8.17)
+
Ph
Si
kET 3C60 +
Ph
Si
(8.18)
Me n Me n
The photochemical addition of some cyclic oligosilanes to C60 has also been
found interesting. Scheme 8.8 shows some examples of such a transformation.
Irradiation (l > 300 nm) of a toluene solution of disilirane 36 with C60 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 C60 is demonstrated, indicating the role of C60
as sensitizer [38]. The photoinduced reactions of disilirane 36 with higher
fullerenes such as C70, C 76(D2), C78(C2v)and C84(D2) have also been reported
[39,40].
R 2 Si
SiR 2
37, 82%
R
Si Si
R R
36
R
C 60
R Si Si
R R
38
Ph Ph
Ph Si Si
Ph Si Si
Ph Ph
40
Ph
Ph
R
R 2Si
39, 61%
R 2
Si
Ph
Ph
Si
Ph Si
Ph Si Si Ph H
PhPh
Scheme 8.8 Photochemical (l > 300 nm) addition of cyclic oligosilanes to C60
41, 87%