Chiral Cycloparaarylenes Incorporating Binaphthyl Units: Dramatic Effects of Peripheral Functionalization on (Chir)Optical Properties.

Authors

Kazuto Takaishi, Kotaro Nakahara, Kasumi Nishiyama, Tadashi Ema

Published in

Chemistry (Weinheim an der Bergstrasse, Germany). Pages e71771. Oct 08, 2026. Epub Oct 08, 2026.

Abstract

Axially chiral [12]cycloparaarylenes 1 and 2, consisting of three each of 1,1'-binaphthyl and biphenyl units, were synthesized. Their characteristics were distinct from those of [12]cycloparaphenylene and depended on whether the 2,2'-substituents on the binaphthyls were methoxy groups or a methylenedioxy bridge. 1 with methoxy groups adopted a D₃-symmetric structure with transoid binaphthyls, whereas 2 with methylenedioxy groups existed as an equilibrium mixture of C₃- and C₁-symmetric structures with cisoid binaphthyls. This difference arises from modulation in binaphthyl dihedral angles and the intrinsic preference of cycloparaarylenes (CPAs) for cylindrical arene arrangements. 1 displayed strong aggregation-induced emission enhancement (AIEE) with Φ_fl of 0.85 at 5°C and blue emission in the solid state. 2 showed weaker but more redshifted AIEE and solid-state green emission. Trifluoroacetic acid molecules stabilized the highly symmetric conformations of 1 in the excited state, leading to a ninefold enhancement in fluorescence (FL) and intense circularly polarized luminescence (CPL) with |g_lum| of 0.028 and B_CPL of 820 M^-1 cm^-1 at -60°C.

PMID:
42845023
Bibliographic data and abstract were imported from PubMed on 08 Oct 2026.

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