binaphthyl units. In this section, an approach for the facile control of the CPL signs
of chiral binaphthyl fluorophores involving the external solid-state environment is
reported; (S)-2,2
0 -diethoxy-1,1
0 -binaphthyl [(S)-1] is used in this section as a model
optically active binaphthyl fluorophore (Fig. 2.11). As the solid-state environment,
organic poly(methyl methacrylate) (PMMA) and inorganic KBr are used.
The PL and CPL spectra of (S)-1 in the PMMA film-dispersed state and the KBr
pellet-dispersed state were acquired, as shown in Fig. 2.12. (S)-1 dispersed in
PMMA and KBr exhibited PL maxima (λ PL ) at 373 and 377 nm, respectively,
with corresponding PL quantum yields (Ф F ) of 45% and 54%. Characteristically,
the values of Ф F for (S)-1 were higher in the solid state than in CHCl 3 solution,
which is possibly due to the suppression of vibrational deactivation of the molecule
in the solid state.
(S)-1 emits CPL both in the PMMA film-dispersed state and the KBr pelletdispersed state. Surprisingly, (S)-1 exhibited opposite CPL signs in these two
states: positive (+) for the PMMA state and negative (À) for the KBr state. (S)-1
has g CPL values in the PMMA film and KBr pellet states of about +7.9 Â 10
–4 and
À4.4 Â 10
–4 , respectively. The |g CPL | values of (S)-1 in the PMMA and KBr states
were slightly smaller than that of the CHCl 3 solution (g CPL ¼ +1.0 Â 10
–3
).
The CD and UV-Vis absorption spectra of (S)-1 in the PMMA film- and KBr
pellet-dispersed states were also acquired (Fig. 2.13). Several UV-Vis bands were
Fig. 2.11 Chiral binaphthyl
fluorophore (S)-1
0.0
1.0
2.0
3.0
4.0
5.0
340
380
420
-30
-25
-20
-15
-10
-5
0
5
10
15
DC / V
CPL / mdeg
Wavelength / nm
Fig. 2.12 CPL (upper) and
PL (lower) spectra of (S)-1
in PMMA film-dispersed
(black) and KBr pelletdispersed (red) states
2 Circularly Polarized Luminescence of Axially Chiral Binaphthyl Fluorophores
19
of chiral binaphthyl fluorophores involving the external solid-state environment is
reported; (S)-2,2
0 -diethoxy-1,1
0 -binaphthyl [(S)-1] is used in this section as a model
optically active binaphthyl fluorophore (Fig. 2.11). As the solid-state environment,
organic poly(methyl methacrylate) (PMMA) and inorganic KBr are used.
The PL and CPL spectra of (S)-1 in the PMMA film-dispersed state and the KBr
pellet-dispersed state were acquired, as shown in Fig. 2.12. (S)-1 dispersed in
PMMA and KBr exhibited PL maxima (λ PL ) at 373 and 377 nm, respectively,
with corresponding PL quantum yields (Ф F ) of 45% and 54%. Characteristically,
the values of Ф F for (S)-1 were higher in the solid state than in CHCl 3 solution,
which is possibly due to the suppression of vibrational deactivation of the molecule
in the solid state.
(S)-1 emits CPL both in the PMMA film-dispersed state and the KBr pelletdispersed state. Surprisingly, (S)-1 exhibited opposite CPL signs in these two
states: positive (+) for the PMMA state and negative (À) for the KBr state. (S)-1
has g CPL values in the PMMA film and KBr pellet states of about +7.9 Â 10
–4 and
À4.4 Â 10
–4 , respectively. The |g CPL | values of (S)-1 in the PMMA and KBr states
were slightly smaller than that of the CHCl 3 solution (g CPL ¼ +1.0 Â 10
–3
).
The CD and UV-Vis absorption spectra of (S)-1 in the PMMA film- and KBr
pellet-dispersed states were also acquired (Fig. 2.13). Several UV-Vis bands were
Fig. 2.11 Chiral binaphthyl
fluorophore (S)-1
0.0
1.0
2.0
3.0
4.0
5.0
340
380
420
-30
-25
-20
-15
-10
-5
0
5
10
15
DC / V
CPL / mdeg
Wavelength / nm
Fig. 2.12 CPL (upper) and
PL (lower) spectra of (S)-1
in PMMA film-dispersed
(black) and KBr pelletdispersed (red) states
2 Circularly Polarized Luminescence of Axially Chiral Binaphthyl Fluorophores
19