Bulky, Solid…but still Topochemical!

Significance

The topochemical reaction converting butadiyne into polydiacetylene elegantly yields pure, well-defined conjugated polymers in the crystalline or gel state. These reactions have been almost exclusively performed with flexible alkyl chains at both ends of the butadiyne moiety to allow for the necessary structural changes to occur within the crystal lattice during the polymerization process. Bulky aryl groups reluctant to undergo significant conformational changes in solid-state crystals usually nullify the progress of this ­reaction. However, here the authors report the efficient preparation of a polydiacetylene (P1) from diarylbutadiyne 1 in both gel and solid states using UV irradiation.