Establishing design principles to create nonplanar π-conjugated molecules is crucial for the development of novel functional materials. Herein, we describe the synthesis and properties of dinaphtho-[1,8-bc:1′,8′-ef ]azepine bisimides (DNABIs). Their molecular design is conceptually based on the insertion of a nitrogen atom into a perylene bisimide core. We have synthesized several DNABI derivatives with a hydrogen atom, a primary alkyl group, or an aryl group on the central nitrogen atom. These DNABIs exhibit nonplanar conformations, flexible structural changes, and ambipolar redox activity. The steric effect around the central nitrogen atom substantially affects the overall structures and results in two different conformations: a nonsymmetric bent conformation and a symmetric twisted conformation, accompanied by a drastic change in electronic properties. Notably, the nonsymmetric DNABI undergoes unique structural changes in response to the application of an external electric field, which is due to molecular motions that are accompanied by an orientational fluctuation of the dipole moment. Furthermore, the addition of a chiral Brønsted base to N-unsubstituted DNABI affords control over the helical chirality via hydrogen-bonding interactions.
Bibliographical noteFunding Information:
This work was supported by JSPS KAKENHI Grant JP17H01190 (H.S.) and Grant JP19H00886 (T.A.). T.A. acknowledges JST CREST Grant JPMJCR18I4 and “Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials” from MEXT. N.F. gratefully acknowledges the Tatematsu Foundation for financial support. The authors acknowledge Prof. Dr. Makoto Yamashita and Dr. Katsunori Suzuki for XRD measurements, as well as Prof. Dr. Eiji Yashima and Dr. Daisuke Taura for CD measurements. We also thank Fumito Ueoka in Ooi group for preparation of 10 . The work at Yonsei University was supported by the Strategic Research (Grant NRF2016R1E1A1A01943379) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry