278
T. Mutai
Fig. 14.3 Absorption and luminescence spectra of 1-BG (dashed line) and 1-Y (solid line).
Modified from Mutai et al. [61] with permission from WIELY-VCH
Table 14.1 Absorption (Kubelka-Munk spectrum) and emission of 1 and MeOPIP in various solid
states
λ abs /nm a
λ em /nm (Φ)
τ /ns
HPIP (1)
Crystal 1-BG
339
496 (0.50)
5.91
Crystal 1-Y
337
529 (0.37)
5.84
Amorphous
337
527 (0.39)
6.39
MeOPIP
Powder
312
382 (0.24)
2.75
Modified from Mutai et al. [61] with permission from WIELY-VCH
well within the range of typical ESIPT fluorescence [39, 77]. Thus, ESIPT luminescence is dependent on the molecular packing mode in the solid state, probably
because the emitting species has zwitterionic character, which is sensitive to the
molecular conformation and field effects of surrounding molecules.
On the other hand, the 2
-methoxy derivative MeOPIP (Scheme 14.5), which does
not form intramolecular hydrogen bonds, showed only blue, normal fluorescence
(382 nm) in the solid state.
Scheme 14.5 Molecular structures of 1 Enol , 1 IPT , and MeOPIP
T. Mutai
Fig. 14.3 Absorption and luminescence spectra of 1-BG (dashed line) and 1-Y (solid line).
Modified from Mutai et al. [61] with permission from WIELY-VCH
Table 14.1 Absorption (Kubelka-Munk spectrum) and emission of 1 and MeOPIP in various solid
states
λ abs /nm a
λ em /nm (Φ)
τ /ns
HPIP (1)
Crystal 1-BG
339
496 (0.50)
5.91
Crystal 1-Y
337
529 (0.37)
5.84
Amorphous
337
527 (0.39)
6.39
MeOPIP
Powder
312
382 (0.24)
2.75
Modified from Mutai et al. [61] with permission from WIELY-VCH
well within the range of typical ESIPT fluorescence [39, 77]. Thus, ESIPT luminescence is dependent on the molecular packing mode in the solid state, probably
because the emitting species has zwitterionic character, which is sensitive to the
molecular conformation and field effects of surrounding molecules.
On the other hand, the 2
-methoxy derivative MeOPIP (Scheme 14.5), which does
not form intramolecular hydrogen bonds, showed only blue, normal fluorescence
(382 nm) in the solid state.
Scheme 14.5 Molecular structures of 1 Enol , 1 IPT , and MeOPIP