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Updated: Mar 8, 2026

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Macrocyclic Oligothiophene with Stereogenic [2.2]Paracyclophane Scaffolds: Chiroptical Properties from π-Transannular
Masashi Hasegawa1, Kosuke Kobayakawa1, Hideyo Matsuzawa1
1Department of Chemistry, Graduate School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan.
Abstract:
The enantiomers of a new cyclic oligothiophene, bridged by two pseudo-ortho[2.2]paracyclophanes, were synthesized as a new class of the chiral π-conjugated system. Single-crystal X-ray diffraction analysis revealed a twisted structure for these oligothiophenes induced by a torsion of the cyclophane moieties. The embedding oligothiophenes into the inherent planar chirality provided a significant enhancement in circular dichroism (CD) spectra thanks to the large magnetic/electric transition dipole moments. In the dicationic state, an intramolecular π dimer was formed due to the strong interactions of the oligothiophenes. We further recorded unprecedented wide ranges of CD spectra in 250-1800 nm region. The transitions are reasonably described by the exciton coupling of the oligothiophenes.
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