Chapter 9
Circularly Polarized Luminescence
of Chirally Arranged Achiral Organic
Luminophores by Covalent
and Supramolecular Methods
Toshiaki Ikeda and Takeharu Haino
Abstract Circularly polarized luminescence (CPL) produced by achiral organic
luminophores is described. Achiral organic luminophores can exhibit CPL by
the chiral arrangement of the achiral luminophores. Chiral arrangement of achiral
luminophores can be constructed through a covalently linked chiral spacer like
a binaphthyl moiety. A helical supramolecular assembly also provides chiral
environment on an achiral luminophore. The helically stacked assemblies of
achiral luminophores are excellent for realizing CPL of the achiral luminophore since
the highly assembled structure in the helical assembly provides good CPL activity. The
stimuli-responsivity of supramolecular systems provides stimuli-responsive CPL.
9.1 Introduction
In the field of circularly polarized luminescence (CPL), chiral lanthanide complexes
have been dominant due to their large CPL dissymmetry factor, g lum [1]. In recent
years, CPL-active organic compounds have attracted growing interest toward
their potential applications in optoelectronic devices [2, 3]. The early research on
CPL-active organic molecules started with chiral ketones in the 1960s [4]. After
that, various CPL-active organic compounds were developed, and some of them
exhibit large g lum values comparable to those of chiral lanthanide complexes.
A key issue for constructing CPL-active materials is how to prepare an
asymmetric environment on luminophores. A straightforward strategy for realizing
CPL-active materials is the direct introduction of chirality on the luminophore.
Actually, many lanthanide complexes possessing chiral ligands have been reported
T. Ikeda
Department of Chemistry, School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
T. Haino (*)
Department of Chemistry, Graduate School of Science, Hiroshima University, Hiroshima, Japan
e-mail: haino@hiroshima-u.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
T. Mori (ed.), Circularly Polarized Luminescence of Isolated Small Organic
Molecules, https://doi.org/10.1007/978-981-15-2309-0_9
197
Circularly Polarized Luminescence
of Chirally Arranged Achiral Organic
Luminophores by Covalent
and Supramolecular Methods
Toshiaki Ikeda and Takeharu Haino
Abstract Circularly polarized luminescence (CPL) produced by achiral organic
luminophores is described. Achiral organic luminophores can exhibit CPL by
the chiral arrangement of the achiral luminophores. Chiral arrangement of achiral
luminophores can be constructed through a covalently linked chiral spacer like
a binaphthyl moiety. A helical supramolecular assembly also provides chiral
environment on an achiral luminophore. The helically stacked assemblies of
achiral luminophores are excellent for realizing CPL of the achiral luminophore since
the highly assembled structure in the helical assembly provides good CPL activity. The
stimuli-responsivity of supramolecular systems provides stimuli-responsive CPL.
9.1 Introduction
In the field of circularly polarized luminescence (CPL), chiral lanthanide complexes
have been dominant due to their large CPL dissymmetry factor, g lum [1]. In recent
years, CPL-active organic compounds have attracted growing interest toward
their potential applications in optoelectronic devices [2, 3]. The early research on
CPL-active organic molecules started with chiral ketones in the 1960s [4]. After
that, various CPL-active organic compounds were developed, and some of them
exhibit large g lum values comparable to those of chiral lanthanide complexes.
A key issue for constructing CPL-active materials is how to prepare an
asymmetric environment on luminophores. A straightforward strategy for realizing
CPL-active materials is the direct introduction of chirality on the luminophore.
Actually, many lanthanide complexes possessing chiral ligands have been reported
T. Ikeda
Department of Chemistry, School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
T. Haino (*)
Department of Chemistry, Graduate School of Science, Hiroshima University, Hiroshima, Japan
e-mail: haino@hiroshima-u.ac.jp
© Springer Nature Singapore Pte Ltd. 2020
T. Mori (ed.), Circularly Polarized Luminescence of Isolated Small Organic
Molecules, https://doi.org/10.1007/978-981-15-2309-0_9
197