1,3-Butadiynes, topochemical polymerization

More recent developments exploit the energy content of readily accessible cycloalkynes based on phenyl-alkynyl structural motives, albeit not always with fullerene formation in mind. For example, the strained dehydrobenzoannulene 4 [19] could be converted by light, heat (145 °C), or pressure (20000 psi) in a topochemical polymerization reaction typical for butadiynes to a deeply coloured polymer. A similar thermochemical behaviour (strongly exothermic transformation around 200 °C) was observed for compounds 5 and 6 [20]. However, none of the systems 4-6 shows any tendency to produce spherical forms of carbon under the conditions investigated. 

Scheme 11-4 Topochemically controlled solid-state polymerization pattern of 1,3-butadiynes.

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