Chemistry Reference
In-Depth Information
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SCHEME 5.1
Different stiff and rigid dendrimers
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pathway. For other dendrimers with extended cores or more flexible dendrons, a
combination of both approaches could be applied to achieve faster growth of higher
generation dendrimers, for example, G2-G4-G6 with a second-generation end
functionalized dendron.
Since some reviews on functional polyphenylene dendrimers have been pub-
lished [13-17,26], the aim here is to focus on more recent achievements, while briefly
introducing the whole concept to begin with.
5.2 SYNTHESIS
The synthesis of polyphenylene dendrimers is mainly based on two reactions with
nearly no side products and close to quantitative yields as the (i) growth step via
Diels-Alder cycloaddition between cyclopentadienones and ethynylenes and the
(ii) deprotection step via desilylation of triisopropyl-substituted alkynes [13,25].
The functionalized tetraphenyl-cyclopentadienones
containing two (A
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B) or four
triisopropylsilylethenyl (A
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B) groups were chosen as building blocks for the
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