Chapter 10
Circularly Polarized Luminescence
(CPL) Based on Planar Chiral
[2.2]Paracyclophane
Yasuhiro Morisaki
Abstract In this chapter, chiroptical properties, especially circularly polarized luminescence (CPL) properties of optically active molecules based on planar chiral
[2.2]paracyclophane are mainly introduced. In addition, practical optical resolution methods of disubstituted and tetrasubstituted [2.2]paracyclophane molecules
are also focused on. The enantiopure [2.2]paracyclophane compounds have been
used as chiral building blocks to synthesize the optically active molecules by
means of optical resolution. The [2.2]paracyclophane-based molecules are π-stacked
molecules, which construct optically active second-ordered structures, such as V-,
X-, triangle-shaped, and one-handed double helical structures, due to the orientation
of stacked π-electron systems. Photoexcitation allows them to emit bright CPL with
good photoluminescence (PL) quantum efficiencies and large dissymmetry factors
(g lum values). Thus, planar chiral [2.2]paracyclophane is the ideal scaffold to achieve
excellent CPL properties.
Keywords Circularly polarized luminescence · [2.2]Paracyclophane · Planar
chirality
10.1 Introduction: Circularly Polarized Luminescence
(CPL)
Circularly polarized luminescence (CPL) is a chiroptical (chiral + optical) property
that is responsible for the difference in luminescence intensity between left-handed
and right-handed emissions. Circular dichroism (CD) is another chiroptical property
that is responsible for the difference in molar extinction coefficients between leftand right-polarized light. CPL and CD spectroscopy provide important information
about the orientation of luminophores and chromophores, respectively (Berova et al.
2000). Many optically active molecules exhibit CPL and CD in the excited and
Y. Morisaki (B)
School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
e-mail: ymo@kwansei.ac.jp
© Springer Nature Singapore Pte Ltd. 2021
Y. Ooyama and S. Yagi (eds.), Progress in the Science of Functional Dyes,
https://doi.org/10.1007/978-981-33-4392-4_10
343
Circularly Polarized Luminescence
(CPL) Based on Planar Chiral
[2.2]Paracyclophane
Yasuhiro Morisaki
Abstract In this chapter, chiroptical properties, especially circularly polarized luminescence (CPL) properties of optically active molecules based on planar chiral
[2.2]paracyclophane are mainly introduced. In addition, practical optical resolution methods of disubstituted and tetrasubstituted [2.2]paracyclophane molecules
are also focused on. The enantiopure [2.2]paracyclophane compounds have been
used as chiral building blocks to synthesize the optically active molecules by
means of optical resolution. The [2.2]paracyclophane-based molecules are π-stacked
molecules, which construct optically active second-ordered structures, such as V-,
X-, triangle-shaped, and one-handed double helical structures, due to the orientation
of stacked π-electron systems. Photoexcitation allows them to emit bright CPL with
good photoluminescence (PL) quantum efficiencies and large dissymmetry factors
(g lum values). Thus, planar chiral [2.2]paracyclophane is the ideal scaffold to achieve
excellent CPL properties.
Keywords Circularly polarized luminescence · [2.2]Paracyclophane · Planar
chirality
10.1 Introduction: Circularly Polarized Luminescence
(CPL)
Circularly polarized luminescence (CPL) is a chiroptical (chiral + optical) property
that is responsible for the difference in luminescence intensity between left-handed
and right-handed emissions. Circular dichroism (CD) is another chiroptical property
that is responsible for the difference in molar extinction coefficients between leftand right-polarized light. CPL and CD spectroscopy provide important information
about the orientation of luminophores and chromophores, respectively (Berova et al.
2000). Many optically active molecules exhibit CPL and CD in the excited and
Y. Morisaki (B)
School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Japan
e-mail: ymo@kwansei.ac.jp
© Springer Nature Singapore Pte Ltd. 2021
Y. Ooyama and S. Yagi (eds.), Progress in the Science of Functional Dyes,
https://doi.org/10.1007/978-981-33-4392-4_10
343