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Fig. 12 Insertion of 2-carbon
fragment into C60. Reprinted
with permission from [
77
].
Copyright 2003 American
Chemical Society
Scheme 16 One-pot synthesis of C
62
analogue 55. Reprinted with permission from [
77
]. Copy-
right 2003 American Chemical Society
Unfortunately, insolubility prevented some NMR studies and X-ray analysis. How-
ever, DFT and NICS calculations of 54a indicated that the central ring has greater
diatropic character than the triangular [7]phenylene with linear arms.
There is also interest in incorporating rings of different sizes into the standard
C
60
skeleton, in the hope of creating new functional materials. Rubin and coworkers
proposed a conceptual approach for inserting a two-carbon fragment into fullerene
to generate C
62
in 2000 (Fig.
12
)[
78
]. Attempts to isolate the parent hydrocarbon
C
62
were not successful, likely due to its predicted high reactivity. Therefore the
authors turned to a related system that allowed them to access diaryl-C
62
55 [
77
].
The one-pot reaction, commencing with the Diels-Alder reaction of diaryltetrazine
