developing various kinds of molecules for CPL research. Among these gelatons,
sugar, cholesterol and amino acid derivatives are frequently used. However, only
one kind of enantiomers of sugar and cholesterol could be easily obtained, while it
is relatively easier to obtain both the L- and D-enantiomers for amino acids. Thus,
CPL-active materials derived from amino acids are extensively investigated.
11.3 CPL from Gelator Molecules and Their Gels
11.3.1 CPL-Active Simple Molecules with Enhanced Circular
Polarization via Self-Assembly
For fabricating chiral luminescent molecules, introduction of a luminescent moiety
to nonluminous chiral moiety through covalent bond is a general strategy [14].
In this case, lots of chiral moieties bonding with aromatic π-conjugated chromophore
exhibited CPL activity have been widely investigated. For example, Kawai
and Nakashima et al. reported the CPL from an axial chiral binaphthyl
derivatives, in which two perylene bisimides were bonded. The monomeric state
in chloroform (molecule 1, Fig. 11.4a) showed the g lum value as low as 3 Â 10
À3
[15]. However, the assembly of 1 resulted in almost one order of magnitude
higher g lum value. In addition, the morphology of the assemblies played a
crucial role in deciding the luminescence dissymmetry. These studies elegantly
demonstrated that chiral assemblies could act as an efficient approach to amplify
the luminescent dissymmetry factor of simple organic molecules. C 2 -symmetrical
chiral 1,2-diaminocyclohexane was also used as a chiral source for designing the
CPL-active compounds. Strong CPL activity was reported from molecules 2 and
3 (Fig. 11.4b) [20]. For the properties of CPL we could get, the force of the
noncovalent interactions, the competition of the chiral and achiral interactions, and
the length of fluorophore to the chiral center all have effect. Chiral simple molecules
with CPL activity have attracted great interests in recent years and extensive
Fig. 11.4 (a) Molecular structure of chiral binaphthyl derivatives 1. (b) Molecular structures of
chiral diaminocyclohexane derivatives 2 and 3
11 Circularly Polarized Luminescence from Gelator Molecules: From Isolated. . .
253
sugar, cholesterol and amino acid derivatives are frequently used. However, only
one kind of enantiomers of sugar and cholesterol could be easily obtained, while it
is relatively easier to obtain both the L- and D-enantiomers for amino acids. Thus,
CPL-active materials derived from amino acids are extensively investigated.
11.3 CPL from Gelator Molecules and Their Gels
11.3.1 CPL-Active Simple Molecules with Enhanced Circular
Polarization via Self-Assembly
For fabricating chiral luminescent molecules, introduction of a luminescent moiety
to nonluminous chiral moiety through covalent bond is a general strategy [14].
In this case, lots of chiral moieties bonding with aromatic π-conjugated chromophore
exhibited CPL activity have been widely investigated. For example, Kawai
and Nakashima et al. reported the CPL from an axial chiral binaphthyl
derivatives, in which two perylene bisimides were bonded. The monomeric state
in chloroform (molecule 1, Fig. 11.4a) showed the g lum value as low as 3 Â 10
À3
[15]. However, the assembly of 1 resulted in almost one order of magnitude
higher g lum value. In addition, the morphology of the assemblies played a
crucial role in deciding the luminescence dissymmetry. These studies elegantly
demonstrated that chiral assemblies could act as an efficient approach to amplify
the luminescent dissymmetry factor of simple organic molecules. C 2 -symmetrical
chiral 1,2-diaminocyclohexane was also used as a chiral source for designing the
CPL-active compounds. Strong CPL activity was reported from molecules 2 and
3 (Fig. 11.4b) [20]. For the properties of CPL we could get, the force of the
noncovalent interactions, the competition of the chiral and achiral interactions, and
the length of fluorophore to the chiral center all have effect. Chiral simple molecules
with CPL activity have attracted great interests in recent years and extensive
Fig. 11.4 (a) Molecular structure of chiral binaphthyl derivatives 1. (b) Molecular structures of
chiral diaminocyclohexane derivatives 2 and 3
11 Circularly Polarized Luminescence from Gelator Molecules: From Isolated. . .
253