Synthesis and solid-state polymerization of triyne and enediyne derivatives with similar π-conjugated structures

Three diacetylene monomer model compounds with similar pi-conjugation systems, 10-phenyl-5,7,9-decatriynyl N-phenylcarbamate (1), (E)-10-phenyldec-9-en-5,7-diynyl N-phenylcarbamate (2), and (E)-10-phenyldec-5-en-7,9-diynyl N-phenylcarbamate (3). were synthesized and their properties and solid-state polymerization were investigated. Based on the absorption spectra of the monomers, it was found that the conjugation effect of a double bond was different from that of a triple bond in solution. Monomers 1, 2, and 3 gave one, two, and five crystal forms, respectively, of which 1 and one of the crystal forms of 2 (2a) could be polymerized in the solid state. The conversions after gamma-ray irradiation (1 MGy dose) were 53% and 20%, respectively. The longest-wavelength absorption maxima of the polymers prepared from 1 and 2a were 645 and 655 nm, respectively. The polymerizable crystals 1 and 2a were found to have layered monomer structures with spacing of 3.1-3.6 nm. Based on solid-state C-13 NMR spectra, the polymerization sites of I were determined to be the 1,4- and 16-positions with respect to the phenyl ring, and that of 2a was determined to be the 3,6-position with respect to the phenyl ring.