exhibited CPL with a g lum value of À0.32, which is quite higher than those of other
solid samples.
As described herein, supramolecular assemblies that have chirality, especially the
helical assemblies, exhibited excellent CPL properties. Highly assembled structures
of the luminophore bring about high g lum values [2].
9.5 Stimuli-Responsive CPL Using a Supramolecular
Assembly
A notable feature of CPL-active organic compounds is the stimuli-responsiveness
of CPL. Organic compounds that exhibit stimuli-responsivity have been
widely developed since organic compounds have flexible conformations. For
example, 32 and 33, photoresponsive CPL-active polymers possessing the
photochromic dithienylethene moiety, have been developed by Akagi and
coworkers (Fig. 9.16) [48]. A supramolecular assembly is constructed by
reversible intermolecular interactions, and thus, one can control the assembly
and disassembly of the supramolecular system by external stimuli. Therefore,
Ar
S
S
O
O
O
O
OR
F
F
F
F
F
F
n
Ar
S
S
O
O
O
O
OR
F
F
F
F
F
F
n
UV
Vis
R =
O
(S)-32: Ar=
(S)-33: Ar=
S
S
Fig. 9.16 Photoresponsive CPL-active polymer
9 Circularly Polarized Luminescence of Chirally Arranged Achiral Organic. . .
213