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Circularly Polarized Luminescence Liquids Based on Siloxybinaphthyls: Best Binaphthyl Dihedral Angle in the Excited State
Author(s) -
Takaishi Kazuto,
Matsumoto Tomoki,
Kawataka Miyu,
Ema Tadashi
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202101226
Subject(s) - dihedral angle , excited state , luminescence , chemistry , crystallography , dipole , materials science , atomic physics , molecule , physics , organic chemistry , hydrogen bond , optoelectronics
A series of axially chiral 1,1′‐binaphthyls with trialkylsiloxy (OSiR 3 ) groups were synthesized. Among them, 1 a – c possessing OSiR 3 groups at the 7,7′‐positions and methyl groups at the 2,2′‐positions were liquids at room temperature, and the neat liquids showed circularly polarized luminescence (CPL) (R=Bu; Φ fl,liquid =0.21, | g lum,liquid |=1.6×10 −3 ). The | g lum,liquid | value is the highest of pure liquids. These compounds remained liquid over a broad range of temperatures, down to −50 °C. Time‐dependent DFT calculations indicated that in the excited state, the binaphthyls adopt a transoid conformation with a small angle between the electric and magnetic transition dipole moments ( θ μ , m =77°), which is a key factor in their CPL activity. The best binaphthyl dihedral angle in the excited state is approximately 110°.