Perfluorophenyl-Phenyl Interactions in the Crystallization and Topochemical Polymerization of Triacetylene Monomers

A series of symmetrically and unsymmetrically substituted octa-2,4,6-triyne-1,8-diol derivatives with benzoyl, 4-dodecyloxybenzoyl, as well as perfluorobenzoyl substituents were prepared and investigated with respect to their crystal structures and topochemical polymerizability. Single-crystal structures for several of these triacetylene monomers have been obtained and proved that the perfluoro-phenyl-phenyl interactions played a decisive role in the molecular packing. As a consequence of the geometric requirements imposed by the perfluoro-phenyl-phenyl interactions, packing parameters appropriate for a topochemical triacetylene polymerization in the sense of either a 1,6- or a 1,4-polyaddition along different crystallographic axes were observed in two cases, and UV irradiation led to successful polymerization. Raman as well as solid-state C-13 NMR spectra of the obtained polymers revealed that the polymerization had predominantly proceeded in the form of a 1,4-polyaddition.