Synthesis Of Ladder Polymers Composed of Two Polydiacetylenes Linked by Methylene Chains

Abstract Novel polydiacetylene (PDA) derivatives were prepared from the monomers that have two butadiyne parts linked by a methylene chain and their both ends were modified by butoxycarbonylmethyl urethane groups. Polymerization in solid state was performed by UV or γ-ray irradiation and characteristic excitonic absorption of PDA was observed at around 635 nm except for one compound (574 nm). From 13C NMR spectra measured using CP/MAS and from X-ray diffraction experiment, it was clear that the spacer containing four or more methylene groups is needed to form the ladder polymer composed of two PDAs linked by methylene chains, while eight methylene groups in the spacer are necessary to preserve its polymer crystallinity.