Chemistry Reference
In-Depth Information
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( P )-(12,8)-[4]CC
Molar ratio: 22%
Isolated yield: 19%
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( M )-(12,8)-[4]CC
Molar ratio: 22%
Isolated yield: 19%
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( P )-(11,9)-[4]CC
Molar ratio: 19%
Isolated yield: 15%
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( M )-(11,9)-[4]CC
Molar ratio: 19%
Isolated yield: 14%
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(10,10)-[4]CC AABB
Molar ratio: 13%
Isolated yield: 11%
(10,10)-[4]CC ABAB
Molar ratio: 5%
Isolated yield: 4%
Fig. 40 Isomers of [4]CC [ 44 ]
crystallized for X-ray diffraction studies. Nakamura found that this molecule had
remarkable bond consistency. While fullerene exhibits bond length alternation, the
20
-electrons in the cis -annulene equator appeared to be fully delocalized with
bond lengths of 1.40 and 1.43 ˚ . The outer double bonds are much shorter,
conforming more to a Kekul ´ structure than a graphitic model and may be
explained by the geometric constraint of the fullerene skeleton. NCIS calculations
also confirmed the aromaticity of this novel structure [ 68 ]. For the first time, this
synthesis validated the idea that discrete, double-stranded aromatic belts can be
systematically constructed with organic synthesis. These modified fullerene
structures were found to be fluorescent with a quantum yield of
π
ϕ ¼
0.18 and a
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