7.9 Circularly Polarized Luminescence in Propeller
Chirality
The chiral HABs (H1–H6) are only weakly fluorescent. In contrast, chiral heptaarylBODIPY B7 strongly fluoresces at around 640 nm with a relatively large Stokes shift
of 850 cm
À1 . The fluorescence quantum yield is 0.32 at 25
C but is enhanced to
0.45 by reducing the temperature to À120
C. It has been shown that J-type
BODIPY dimers are moderately fluorescent, while H-type dimers are generally
Fig. 7.16 Conformer equilibria for boron heptaaryldipyrromethene B7 and supramolecular dimer
formation facilitated at lower temperatures; the geometry of supramolecular dimer (bottom) optimized at the DFT-D3(BJ)-TPSS/def2-SV(P) level
168
T. Mori
Chirality
The chiral HABs (H1–H6) are only weakly fluorescent. In contrast, chiral heptaarylBODIPY B7 strongly fluoresces at around 640 nm with a relatively large Stokes shift
of 850 cm
À1 . The fluorescence quantum yield is 0.32 at 25
C but is enhanced to
0.45 by reducing the temperature to À120
C. It has been shown that J-type
BODIPY dimers are moderately fluorescent, while H-type dimers are generally
Fig. 7.16 Conformer equilibria for boron heptaaryldipyrromethene B7 and supramolecular dimer
formation facilitated at lower temperatures; the geometry of supramolecular dimer (bottom) optimized at the DFT-D3(BJ)-TPSS/def2-SV(P) level
168
T. Mori