Binaphthyl-derived armchair-type molecular carbon rings with chirality: synthesis and optical properties†

Herein, we report the synthesis of binaphthyl-derived hoop-shaped aromatic hydrocarbon enantiomers (RCR and SCR) as the segments of (9,9) armchair CNTs. After the structures were identified by HR-MS (MALDI-TOF) and NMR spectroscopy, further circular dichroism (CD) analysis confirmed their chirality. Unlike most of the previously reported chiral-type CNT segments in which chirality arises from the absence of a plane of symmetry or an inversion center in the molecule, the chirality for RCR and SCR is assigned to the introduction of foreign chiral sources, namely, oxyethyl-modified binaphthyl units. Finally, their photophysical properties were also investigated by absorption and fluorescence spectroscopies.