5 BODIPY Dyes and Their Analogues
155
exhibits efficient singlet oxygen generation with a Φ value of 0.32 upon irradiation
with a 690-nm laser. Replacement of the aryl group with a styryl group leads to a
significant redshift (SBDPiR755: λ max = 750 nm, SBDPiR790: λ max = 786 nm)
(Fig. 5.37f) (Awuah et al. 2013). Introduction of the dimethylamino group is a more
efficient approach to realize the red shift of λ max (SBDPiR840 (Awuah et al. 2013):
λ max = 841 nm) (Fig. 5.37a). The 2-thienyl derivative 44 (Kubota et al. 2019) (λ max =
812 nm, F max = 916 nm, Φ f = 0.02) shows a blueshift of λ max , redshift of F max , and
an increase in Φ f compared with those of the trifluoromethyl derivative SBDPiR840
(Fig. 5.37g). Thiphene-fused BODIPY 44 has been applied to NIR photosensitisers
for dye-sensitized solar cells; the maximum IPCE and power conversion efficiency
are 12.3% at 810 nm and 1.12%, respectively (Kubota et al. 2019).
Indole-fused BODIPY dyes have also been reported (Luo et al. 2014; Zhou et al.
2015b). The λ max value of indole-fused BODIPY 45 (Zhou et al. 2015b) (λ max =
608 nm) is more redshifted than that of the benzofuran-fused derivative 36 (λ max =
586 nm) and blueshifted than that of the benzothiophene-fused derivative 41 (λ max
= 616 nm) (Figs. 5.36e, 5.37d and 5.38a). Installation of the methoxy group has
little effect on the absorption properties, whereas the Φ f value becomes lower (46:
λ max = 610 nm, Φ f = 0.24). Although little variation is observed in the Φ f value
of 45 (cyclohexane: Φ f = 0.89, acetonitrile: Φ f = 0.96) with increasing solvent
polarity, 46 (cyclohexane: Φ f = 0.89, acetonitrile: Φ f < 0.001) shows a considerable
decrease in Φ f with increasing solvent polarity. Unsymmetrical BODIPY 47 with the
replacement of one indole moiety on 46 by a benzofuran moiety shows blueshifted
Fig. 5.38 Absorption and fluorescence properties of heterocycle-containing [b]-fused BODIPY
dyes
155
exhibits efficient singlet oxygen generation with a Φ value of 0.32 upon irradiation
with a 690-nm laser. Replacement of the aryl group with a styryl group leads to a
significant redshift (SBDPiR755: λ max = 750 nm, SBDPiR790: λ max = 786 nm)
(Fig. 5.37f) (Awuah et al. 2013). Introduction of the dimethylamino group is a more
efficient approach to realize the red shift of λ max (SBDPiR840 (Awuah et al. 2013):
λ max = 841 nm) (Fig. 5.37a). The 2-thienyl derivative 44 (Kubota et al. 2019) (λ max =
812 nm, F max = 916 nm, Φ f = 0.02) shows a blueshift of λ max , redshift of F max , and
an increase in Φ f compared with those of the trifluoromethyl derivative SBDPiR840
(Fig. 5.37g). Thiphene-fused BODIPY 44 has been applied to NIR photosensitisers
for dye-sensitized solar cells; the maximum IPCE and power conversion efficiency
are 12.3% at 810 nm and 1.12%, respectively (Kubota et al. 2019).
Indole-fused BODIPY dyes have also been reported (Luo et al. 2014; Zhou et al.
2015b). The λ max value of indole-fused BODIPY 45 (Zhou et al. 2015b) (λ max =
608 nm) is more redshifted than that of the benzofuran-fused derivative 36 (λ max =
586 nm) and blueshifted than that of the benzothiophene-fused derivative 41 (λ max
= 616 nm) (Figs. 5.36e, 5.37d and 5.38a). Installation of the methoxy group has
little effect on the absorption properties, whereas the Φ f value becomes lower (46:
λ max = 610 nm, Φ f = 0.24). Although little variation is observed in the Φ f value
of 45 (cyclohexane: Φ f = 0.89, acetonitrile: Φ f = 0.96) with increasing solvent
polarity, 46 (cyclohexane: Φ f = 0.89, acetonitrile: Φ f < 0.001) shows a considerable
decrease in Φ f with increasing solvent polarity. Unsymmetrical BODIPY 47 with the
replacement of one indole moiety on 46 by a benzofuran moiety shows blueshifted
Fig. 5.38 Absorption and fluorescence properties of heterocycle-containing [b]-fused BODIPY
dyes