3.3 Optically Active Molecules Based on Planar Chiral [2.2]
Paracyclophane and Their CPL Profiles
Various optically active molecules emitting CPL, synthesized from the chiral building blocks based on planar chiral [2.2]paracyclophane described above, will be
introduced in this section.
Figure 3.10 shows the optically active V-, N-, and W-shaped π-stacked molecules
((R p )-1-3), in which two, three, and four phenylene-ethynylene π-electron systems,
respectively, are stacked at the terminal benzene ring(s) [39]. Figure 3.10 contains an
optically active triangle-shaped π-stacked molecule (R p )-4 consisting of three
phenylene-ethynylene π-electron systems [39]. They were prepared from
enantiopure
pseudo-ortho-disubstituted
[2.2]paracyclophane.
Their
photoluminescence (PL) and CPL spectra in dilute CHCl 3 and the optical data are
shown in Fig. 3.11a.
The PL spectra of (R p )-1-3 were gradually red-shifted, depending on the number
of stacked π-electron systems. Vibronic structures were observed in the PL spectra,
with good PL quantum efficiencies (Φ PL ) of approximately 0.8. The decay curves
could be fitted with a single exponential function, indicating that the emission from
Fig. 3.9 Synthesis of enantiopure bis-(para)-pseudo-meta-4,7,12,15-tetrasubstituted [2.2]
paracyclophanes
38
Y. Morisaki
Paracyclophane and Their CPL Profiles
Various optically active molecules emitting CPL, synthesized from the chiral building blocks based on planar chiral [2.2]paracyclophane described above, will be
introduced in this section.
Figure 3.10 shows the optically active V-, N-, and W-shaped π-stacked molecules
((R p )-1-3), in which two, three, and four phenylene-ethynylene π-electron systems,
respectively, are stacked at the terminal benzene ring(s) [39]. Figure 3.10 contains an
optically active triangle-shaped π-stacked molecule (R p )-4 consisting of three
phenylene-ethynylene π-electron systems [39]. They were prepared from
enantiopure
pseudo-ortho-disubstituted
[2.2]paracyclophane.
Their
photoluminescence (PL) and CPL spectra in dilute CHCl 3 and the optical data are
shown in Fig. 3.11a.
The PL spectra of (R p )-1-3 were gradually red-shifted, depending on the number
of stacked π-electron systems. Vibronic structures were observed in the PL spectra,
with good PL quantum efficiencies (Φ PL ) of approximately 0.8. The decay curves
could be fitted with a single exponential function, indicating that the emission from
Fig. 3.9 Synthesis of enantiopure bis-(para)-pseudo-meta-4,7,12,15-tetrasubstituted [2.2]
paracyclophanes
38
Y. Morisaki