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Macrocyclic Oligothiophene with Stereogenic [2.2]Paracyclophane Scaffolds: Chiroptical Properties from π‐Transannular Interactions
Author(s) -
Hasegawa Masashi,
Kobayakawa Kosuke,
Matsuzawa Hideyo,
Nishinaga Tohru,
Hirose Takashi,
Sako Katsuya,
Mazaki Yasuhiro
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201605842
Subject(s) - circular dichroism , crystallography , intramolecular force , dimer , chirality (physics) , chemistry , stereocenter , conjugated system , materials science , stereochemistry , enantioselective synthesis , polymer , chiral symmetry , organic chemistry , physics , quantum mechanics , nambu–jona lasinio model , quark , catalysis
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.