Preparation and characterization of macrocyclic butadiyne derivatives for tubular polydiacetylenes

Abstract

Ring monomers with one butadiyne moiety for solid-state polymerization, two amide groups for intermolecular hydrogen bonding, and two 3,4,5-trialkoxyphenyl groups for self-assembling and solubilization were synthesized. Depending on solvent and concentration, the monomers formed the gels. When the monomers solidified from the solutions, the structures of nanofiber aggregates were observed. The FT-IR and X-ray diffraction studies suggested that the ring monomers stacked to formed tubular nanofibers and they were bundled to form the aggregates. From the polymerization behavior monitored by visible diffuse reflectance spectra, regular 1,4-addition of butadiyne moieties was confirmed to be polydiacetylenes but its π-conjugated backbones were distorted. They did not show polymorphism in the solidification conditions performed.

Keywords:

• Gel
• nanofiber
• polydiacetylene
• ring monomer
• tubular polymer

Acknowledgments

The authors thank Prof. Katsuya Maeyama for cooperation on the preparative GPC experiments. The authors also thank Prof. Hiromitsu Maeda and Prof. Yohei Haketa for cooperation on powder X-ray diffraction measurements at SPring-8 (BL40B2; 2019B1452). Theoretical calculations were performed using Research Center for Computational Science, Okazaki, Japan.