Diacetylene-dilution

Figure 60 The synthetic schemes for the diacetylene-diluted (a) alternating (97) (left) and (b) blocky poly( -carborane-disiloxane-diacetylene)s (98). (Adapted from ref. 127.)...

Figure 15.15 Structure of the elastomeric diacetylene-diluted silarylene-siloxane-diacetylene polymer reported by Homrighausen et al.

Cyclodimer 3 proved to be somewhat difficult to manipulate, thus contributing to the complexity of its characterization. The bowed diacetylenic linkages revealed in the X-ray data impart surprising physical characteristics to the molecule. The energy-rich hydrocarbon was sufficiently strained that it decomposed explosively upon grinding (i. e. preparing a Nujol mull) or when heated above 80°C. At room temperature, crystals blackened within a few days and apparently auto-polymerized, even when stored under vacuum in the dark. Only dilute solutions of 3 in benzene or pyridine were fairly stable over time, especially when stored cold under an inert atmosphere. 

The oxidative coupling of long-chain terminal diacetylenes carried out in very dilute solutions gives macrocyclic diacetylenes and polyacetylenes... 

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