N B
N
O
O
(R)-20: R = H
(R)-21: R = Br
(R)-22: R = BTFMP
R
R
R
N B
N
O
O
(R)-24: R = H
(R)-25: R = Br
R
MeO
MeO
OMe
OMe
R
R
N B
N
O
O
Ph Ph
(R)-23
R
acting
chromophore
ICT-switching
moiety
ICT-off CPL
ICT-on CPL
450
500
550
600
650
700
-1.0
-0.5
0.0
0.5
550
600
650
700
750
800
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
450
500
550
600
650
700
0.0
0.5
1.0
550
600
650
700
750
800
0.0
0.5
1.0
20
21
22
23
24
25
Normalized ECD intensity (a.u.)
Wavelength (nm)
Normalized CPL intensity (a.u.)
Wavelength (nm)
Normalized UV intensity (a.u.)
Wavelength (nm)
Normalized emission intensity (a.u.)
Wavelength (nm)
Fig. 6.17 Manipulation of the CPL sign in a set of chiral 1,1
0 -biphen-2-ol-based spiranic O-BODIPYs
by modulating ICT emission by means of selecting electronic factors in both the BODIPY core
(highlighted in red in the molecular structures) and the chelating 1,1
0 -biphen-2-ol (highlighted in blue
in the molecular structures). BTFM: bis(3,5-trifluoromethyl)phenyl [adapted with permission from [52],
published by the Royal Society of Chemistry]
6 BODIPY Based Emitters of Circularly Polarized Luminescence
131