implying the innovative aspect of this study area. Such correlation can be easily
understood as follows. In the rigid aromatic systems, minimal structural changes are
expected in the S 1 state for the relaxation to the emissive state, as they always
provide mirror-imaged absorption and emission spectra. Accordingly, the influence
of the vibrational and structural relaxation in the excited state can be negligible, and
thus the chiroptical properties obtained from the CD and CPL spectra become
consistent with each other, as they originate from the upward and downward
transitions between the same two states. When more carefully analyzed, distinct
(but still linear) correlations are more likely, depending on the molecular structure,
i.e., type of chirality, varying from 0.99 for planar chiral cyclophanes, to 0.93 for
axially chiral biaryls, to 0.77 for chiral BODIPY dyes, and then to 0.61 for helicenes
and related molecules. Nevertheless, the slope of %0.8 obtained of all the g lum -g abs
data reported by 2017 clearly suggests that the dissymmetry of chiral extended π
molecules does not significantly deteriorate on average after the structural relaxation
upon the photoexcitation. Such structural considerations are of paramount importance and would make us available to more sensibly design the further advanced
CPL materials in the future.
Finally, we draw attention to the recent stimulating discoveries such as the
enhanced CPL response through fluorescence resonance energy transfer and for
up-converted emission, as well as the CPL associated with delayed and dual
fluorescence. All these possibilities show that chiral SOMs, especially those of the
extended π-systems, are the most promising candidates for more innovative CPL
materials that are readily accessible, theoretically predictable, rationally designable
and modifiable.
10 3 g abs
10 3
g
lum
0
5
10
20
0
5
10
20
15
15
Fig. 1.3 The g lum -g abs
correlation for of the π-π
Ã
transition in chiral aromatic
molecules. Square,
cyclophanes; triangle,
biaryls; open circle,
helicene-like molecules;
open inverted triangle,
BODIPY derivatives.
Reproduced with
permission [1]. Copyright
2018, Wiley
1 Frontiers of Circularly Polarized Luminescence Chemistry of Isolated Small. . .
9
understood as follows. In the rigid aromatic systems, minimal structural changes are
expected in the S 1 state for the relaxation to the emissive state, as they always
provide mirror-imaged absorption and emission spectra. Accordingly, the influence
of the vibrational and structural relaxation in the excited state can be negligible, and
thus the chiroptical properties obtained from the CD and CPL spectra become
consistent with each other, as they originate from the upward and downward
transitions between the same two states. When more carefully analyzed, distinct
(but still linear) correlations are more likely, depending on the molecular structure,
i.e., type of chirality, varying from 0.99 for planar chiral cyclophanes, to 0.93 for
axially chiral biaryls, to 0.77 for chiral BODIPY dyes, and then to 0.61 for helicenes
and related molecules. Nevertheless, the slope of %0.8 obtained of all the g lum -g abs
data reported by 2017 clearly suggests that the dissymmetry of chiral extended π
molecules does not significantly deteriorate on average after the structural relaxation
upon the photoexcitation. Such structural considerations are of paramount importance and would make us available to more sensibly design the further advanced
CPL materials in the future.
Finally, we draw attention to the recent stimulating discoveries such as the
enhanced CPL response through fluorescence resonance energy transfer and for
up-converted emission, as well as the CPL associated with delayed and dual
fluorescence. All these possibilities show that chiral SOMs, especially those of the
extended π-systems, are the most promising candidates for more innovative CPL
materials that are readily accessible, theoretically predictable, rationally designable
and modifiable.
10 3 g abs
10 3
g
lum
0
5
10
20
0
5
10
20
15
15
Fig. 1.3 The g lum -g abs
correlation for of the π-π
Ã
transition in chiral aromatic
molecules. Square,
cyclophanes; triangle,
biaryls; open circle,
helicene-like molecules;
open inverted triangle,
BODIPY derivatives.
Reproduced with
permission [1]. Copyright
2018, Wiley
1 Frontiers of Circularly Polarized Luminescence Chemistry of Isolated Small. . .
9