12.3 Perylene and Perylene Bisimide-Based Systems
Perylene and derivatives, such as perylene bisimides, are very well-established
fluorophores, thanks to versatile access routes, very high quantum yields with
emission shifted to long wavelengths. Traditionally, in these systems, the excimer
formation is less efficient than with pyrenes. It is usually observed as a broad tailing
along with the very intense and vibronically structured monomer-centered emission.
Despite this limitation, some studies have been reported for which relatively intense
excimer CPL signals have been measured, in particular in the case of designed
intramolecularly-formed excimers.
12.3.1 Excimer CPL from Perylene-Based Systems
Pery-1, prepared in an analogous manner to pyr-1 (vide supra) [11], displays
circularly polarized excimer fluorescence from perylene upon inclusion into a
γ-CDx and subsequent capping via Sonogashira reactions (Fig. 12.7) [31]. For
such a system, CPL with a g lum of |2.1 Â 10
À2 | was recorded (Fig. 12.7). This
value is comparable to that measured for pyr-1 in similar conditions [11].
Following the same synthetic strategy exploited for compounds pyr-27–pyr-29,
Lacour and collaborators prepared diperylene derivatives pery-2–pery-4 (Scheme
12.8) [28]. These systems displayed excimer fluorescence either as a principal
component of the fluorescence spectrum (pery-2 and pery-3) or as a tailing of the
very intense monomer emission (pery-4). In the CPL spectra, two components are
clearly visible; one associated to excimer emission with g lum ca. |10
À3 | and one allied
to monomer fluorescence with a g lum value, ca. |10
À4 |, one order of magnitude lower.
These two components have the same sign with pery-2 and pery-3, but opposite
signs for pery-4. In all these cases, CPL allows for a clear distinction between
monomer and excimer contributions which is not obvious in fluorescence spectra.
Upon Ba
2+ (in CH 3 CN for pery-2) or Na
+ (in CH 2 Cl 2 for pery-2–pery-4) additions,
O
R
O
R
4
4
COOH
HOOC
O
O
NH
O
R =
pery-1
Inouye 2018
Fig. 12.7 Structure of a substituted perylene included in γ-CDx and CPL/total luminescence
spectra measured in H 2 O (pH 9.5, C ¼ 4.5 Â 10
À5 M). Adapted with permission from reference
[31]
286
F. Zinna et al.
Perylene and derivatives, such as perylene bisimides, are very well-established
fluorophores, thanks to versatile access routes, very high quantum yields with
emission shifted to long wavelengths. Traditionally, in these systems, the excimer
formation is less efficient than with pyrenes. It is usually observed as a broad tailing
along with the very intense and vibronically structured monomer-centered emission.
Despite this limitation, some studies have been reported for which relatively intense
excimer CPL signals have been measured, in particular in the case of designed
intramolecularly-formed excimers.
12.3.1 Excimer CPL from Perylene-Based Systems
Pery-1, prepared in an analogous manner to pyr-1 (vide supra) [11], displays
circularly polarized excimer fluorescence from perylene upon inclusion into a
γ-CDx and subsequent capping via Sonogashira reactions (Fig. 12.7) [31]. For
such a system, CPL with a g lum of |2.1 Â 10
À2 | was recorded (Fig. 12.7). This
value is comparable to that measured for pyr-1 in similar conditions [11].
Following the same synthetic strategy exploited for compounds pyr-27–pyr-29,
Lacour and collaborators prepared diperylene derivatives pery-2–pery-4 (Scheme
12.8) [28]. These systems displayed excimer fluorescence either as a principal
component of the fluorescence spectrum (pery-2 and pery-3) or as a tailing of the
very intense monomer emission (pery-4). In the CPL spectra, two components are
clearly visible; one associated to excimer emission with g lum ca. |10
À3 | and one allied
to monomer fluorescence with a g lum value, ca. |10
À4 |, one order of magnitude lower.
These two components have the same sign with pery-2 and pery-3, but opposite
signs for pery-4. In all these cases, CPL allows for a clear distinction between
monomer and excimer contributions which is not obvious in fluorescence spectra.
Upon Ba
2+ (in CH 3 CN for pery-2) or Na
+ (in CH 2 Cl 2 for pery-2–pery-4) additions,
O
R
O
R
4
4
COOH
HOOC
O
O
NH
O
R =
pery-1
Inouye 2018
Fig. 12.7 Structure of a substituted perylene included in γ-CDx and CPL/total luminescence
spectra measured in H 2 O (pH 9.5, C ¼ 4.5 Â 10
À5 M). Adapted with permission from reference
[31]
286
F. Zinna et al.