Title
π-Expanded Axially Chiral Biaryls and Their Emissions: Molecular Design, Syntheses, Optical Resolution, Absolute Configuration, and Circularly Polarized Luminescence of 1,1¤-Bipyrene-2,2¤-diols
Author
Kamrul Hassan, Ken-ichi Yamashita, Kazunori Hirabayashi, Toshio Shimizu, Kazuki Nakabayashi, Yoshitane Imai, Takashi Matsumoto, Akihito Yamano, Ken-ichi Sugiura
Year
2015
Journal
Chemistry Letters
Abstract
Axially chiral biaryls based on pyrene, 1,1¤-bipyrene-2,2¤-diol derivatives 2, were designed and synthesized from 2-hydroxypyrene. Simple optical resolution was carried out and the absolute configuration was determined by diffraction study. Title compounds 2 and corresponding menthylcarbonate 4 showed clear circularly polarized luminescence (CPL) spectra. The degree of dimensionless Kuhn’s anisotropy in the photoexcited state («gem«) of 2 and 4 were ca. 3.6 © 10¹4 and ca. 1.2 © 10¹3 , respectively. Noteworthy properties were as follows: 1) high fluorescent quantum yields of 2 and 4, 0.57 and 0.80, respectively, in marked contrast to that of BINOL, 0.04 and 2) bathochromic shifts of CPL.
Full Article
Instrument
J-820
Keywords
Circular dichroism, Stereochemistry, Cotton effect, Materials