598 Mayuko Uda et al.
tetrahydroxystilbene. 1H-NMR (200 MHz, CD3OD) d 6.18 (2H, s, Ph-4)
6.45 (4H, s, Ph-2, 6) 6.86 (2H, s, ––CH¼¼CH––).
stilbene (200 mg, 0.82 mmol), 18-crown-6-ether (87 mg, 0.33 mmol) and
K2CO3 were reacted in 2-butanone (40 mL) under nitrogen atmosphere and
the mixture was refluxed for 48 h. Conventional workup and purification by
silica-gel column chromatography (eluent chloroform) gave 322 mg of
trans-1 (65%) as a white powder; mp 125–1268C. 1H-NMR (200 MHz,
CDCl3) d 5.07 (8H, s, OCH2Ph) 6.56 (2H, s, stilbene-4,49), 6.75 (4H, s,
stilbene-1,19,5,59), 6.98 (2H, s, olefin), 7.27–7.46 (20H, m, Ph) ppm.
13C-NMR (50 MHz, CDCl3) d 70.16, 101.77, 105.95, 121.05, 127.62,
128.10, 128.69, 136.92, 139.27, 160.26 ppm.
cis-1. THF solution of trans-1 (73.7 mg in 50 mL THF) was irradiated
with 366 nm light of high pressure mercury lamp for 8 h at room
temperature. The isomer ratio ([t]/[c]) of the reaction mixture was 1/2. The
reaction mixture was concentrated in vacuo. Conventional workup and
purification by column chromatography provided 16.8 mg of cis-1. 1H-
NMR (400 MHz, CDCl3) d 4.88 (8H, s, OCH2Ph) 6.48 (2H, t, J¼¼2.4 Hz,
stilbene-4,49), 6.51 (2H, s, olefin), 6.55 (4H, d, J¼¼2.4 Hz, stilbene-
1,19,5,59), 7.28–7.35 (20H, m, Ph) ppm.
trans-2. [G2]-Br (1.51 g, 3.94 mmol), 3,39,5,59-tetrahydroxystilbene (200
mg, 0.82 mmol), 18-crown-6-ether (87 mg, 0.33 mmol) and K2CO3 (580 mg,
4.1 mmol) were reacted in 2-butanone (40 mL) under nitrogen atmosphere
and the mixture was refluxed for 48 h. Conventional workup and purification
by silica-gel column chromatography (eluent: chloroform) gave 782 mg of
trans-2 (65%) as a white powder; mp 146–1478C. MALDI-TOFMS Found:
m/z 1476.5. Calcd for C98H84O12Na: [M1Na]1, 1476.7. 1H-NMR (200
MHz, CDCl3) d 4.99 (4H, s, CH2O––St) 5.02 (4H, s, CH2OPh) 6.56–6.75
(18H, m, Ph) 6.98 (2H, s, olefin) 7.21–7.43 (40H, m, Ph9).
trans-3. [G3]-Br (800 mg, 0.99 mmol), 3,39,5,59-tetrahydroxystilbene
(53 mg, 0.22 mmol), 18-crown-6-ether (23 mg, 0.09 mmol) and K2CO3
(170 mg, 1.2 mmol) were reacted in 2-butanone (30 mL) under nitrogen
atmosphere and the mixture was refluxed for 48 h. Conventional workup
and purification by silica-gel column chromatography (eluent: chloroform)
gave 782 mg of trans-3 (82%) as a colorless glass. MALDI-TOFMS Found:
m/z 3175.1. Calcd for C210H180O28Na: [M1Na]1, 3174.7. 1H-NMR (200
MHz, CDCl3) d 5.07 (56H, m; OCH2Ph) 6.45–6.73 (42H, m; Ph) 6.97 (2H,
s; olefin) 7.22–7.38 (80H, m; Ph) ppm. 13C-NMR (50 MHz, CDCl3) d 70.08,
101.90, 106.15, 127.64, 128.08, 128.66, 136.76, 139.49, 160.45 ppm.
trans-4. [G4]-Br (1.15 g, 0.69 mmol), trans-3,39,5,59-tetrahydroxystil-
bene (40 mg, 0.16 mmol), 18-crown-6-ether (22 mg, 0.08 mmol) and
K2CO3 (230 mg, 1.2 mmol) were reacted in 2-butanone (35 mL) under
nitrogen atmosphere and the mixture was refluxed for 48 h. Conventional
workup and purification by silica-gel column chromatography (eluent:
chloroform–hexane 5 4:1) gave 427 mg of trans-4 (40%) as a colorless
glass. MALDI-TOFMS Found: m/z 6557.8. Calcd for C434H372O60Li:
[M1Li]1, 6554.7. 1H-NMR (400 MHz, CDCl3) d 4.82–4.89 (56H, m,
OCH2Ph), 4.91–4.93 (64H, m, OCH2Ph), 6.43–6.56 (28H, m, Ph), 6.91
(2H, s, olefin), 6.58–6.54 (56H, m, Ph), 7.25–7.36 (160H, m, Ph) ppm.
cis-4. [G4]-Br (2.36 g, 1.42 mmol), cis-3,39,5,59-tetrahydroxystilbene
(84 mg, 3.44 mmol), 18-crown-6-ether (19 mg, 0.07 mmol) and K2CO3
(118.8 mg, 0.86 mmol) were reacted in 2-butanone (50 mL) under nitrogen
atmosphere and the mixture was refluxed for 34 h. Conventional workup
and purification by silica-gel column chromatography (eluent: chloroform–
hexane 5 4:1) gave 854 mg of cis-4 (38%) as a colorless glass. 1H-NMR
(400 MHz, CDCl3) d 4.79–4.85 (56H, m, OCH2Ph), 4.86–4.94 (64H, m,
OCH2Ph), 6.48–6.55 (30H, m, Ph), 6.56–6.60 (56H, m, Ph), 7.26–7.31
(160H, m, Ph) ppm.
cis-3,39,5,59-Tetrahydroxystilbene. Boron tribromide (1.25 g, 5.0 mmol)
in dichloromethane (5 mL) was added to 3,39,5,59-tetramethoxystilbene
(300 mg, 1.0 mmol) in dichloromethane (30 mL) at 08C and the reac-
tion mixture was stirred at room temperature. After 48 h, 20 mL of water
was poured slowly into the reaction mixture, and then 200 mL of water was
added. Conventional workup and purification by silica-gel column
chromatography (eluent: ethylacetate) gave 144 mg (59%) of 3,39,5,59-
tetrahydroxystilbene. 1H-NMR (400 MHz, CD3OD) d 6.21 (2H, s, Ph-4)
6.48 (4H, s, Ph-2, 6) 6.89 (2H, s, ––CH¼¼CH––).
[G2]-OH (40). Benzylbromide (50.0 g, 292.3 mmol), 3,5-dihydroxy-
benzyl alcohol (15.2 g, 146.1 mmol), 18-crown-6-ether (7.72 g, 29.2 mmol)
and potassium carbonate (80 g, 578.6 mmol) were suspended in 2.0 L of 2-
butanone under nitrogen atmosphere. The mixture was heated under reflux
for 60 h. Upon completion of the reaction, the solvent was evaporated
and the water (500 mL) and dichloromethane (200 mL) were added to
the residue. Conventional workup and purification by silica-gel column
chromatography (eluent: hexane–dichloromethane 5 9:1) yielded 14.0 g of
[G2]-OH (60%) as a white needle. 1H-NMR (200 MHz, CDCl3) d 4.64 (2H,
s, CH2OH), 5.05 (4H, s, CH2OPh), 6.56 (1H, t, J 5 2.2 Hz, o-H in Ph), 6.64
(2H, d, J 5 2.2 Hz, o-H in Ph), 7.35–7.42 (10H, m, Ph9) ppm; 13C-NMR
(50 MHz, CDCl3) d 65.45, 70.09, 101.6, 105.80, 127.60, 128.08, 128.68,
136.90, 143.85, 160.03 ppm.
[G2]-Br (40). [G2]-OH (13.6 g, 42.3 mmol) was converted to [G2]-
Br by treatment with CBr4 (17.6 g, 53.1 mmol) and triphenylphosphine
(13.9 g, 53.1 mmol) in THF (85 ml) for 15 min at room temperature.
Conventional workup and purification with silica-gel column chromatog-
raphy (eluent: chloroform) gave 5.04 g of [G2]-Br (31%) as a white needle.
1H-NMR (200 MHz, CDCl3) d 4.42 (2H, s, CH2OH) 5.03 (4H, s, CH2OPh)
6.55 (1H, t, J 5 2.2 Hz, o-H in Ph) 6.65 (2H, d, J 5 2.2 Hz, o-H in Ph)
7.35–7.44 (10H, m, Ph9) ppm; 13C-NMR (50 MHz, CDCl3) d 33.84, 70.04,
102.23, 108.24, 127.63, 128.14, 128.69, 136.63, 139.98, 160.02 ppm.
[G3]-OH (40). [G2]-Br (4.0 g, 10.4 mmol), 3,5-dihydroxybenzyl alcohol
(543 mg, 5.22 mmol), 18-crown-6-ether (552 mg, 2.09 mmol) and K2CO3
(4.3 g, 31.1 mmol) were suspended in 110 mL of 2-butanone under nitrogen
atmosphere and the mixture was heated under reflux for 48 h. Upon com-
pletion of the reaction, the solvent was evaporated and the water (80 mL)
and dichloromethane (80 mL) were added to the residue. Conventional
workup and purification by silica-gel column chromatography (eluent:
chloroform) yielded 2.72 g of [G3]-OH (70%) as a colorless glass. 1H-
NMR (200 MHz, CDCl3) d 4.62 (2H, d, J 5 6 Hz, CH2OH) 4.97 (4H, s,
CH2OPh) 5.03 (8H, s, CH2OPh9) 6.52 (1H, t, J 5 2.2 Hz, p-H in inner Ph)
6.57 (2H, t, J 5 2.2 Hz, o-H in inner Ph) 6.60 (2H, d, J 5 2.2 Hz, p-H in
mid Ph) 6.67 (4H, d, J 5 2.2 Hz, o-H in mid Ph) 7.31–7.43 (20H, m, other
Ph) ppm. 13C-NMR (50 MHz, CDCl3) d 65.55, 70.10, 70.12, 101.6,
101.82, 105.95, 128.08, 106.34, 125.75, 127.74, 127.86, 128.05, 128.17,
128.74, 160.05 ppm.
[G3]-Br (40). [G3]-OH (2.72 g, 3.65 mmol) was converted to [G3]-Br
by treatment with CBr4 (17.6 g, 53.1 mmol) and triphenylphosphine
(13.9 g, 53.1 mmol) in THF (85 mL) for 20 min at room temperature.
Conventional workup and purification by silica-gel column chromatogra-
phy (eluent: chloroform) gave 1.25 g of [G3]-Br (42%) as a colorless glass.
1H-NMR (200 MHz, CDCl3) d 4.40 (2H, s, CH2OH) 4.95 (4H, s, CH2OPh)
5.03 (8H, s, CH2OPh9) 6.51 (1H, t, J 5 2.2 Hz, p-H in inner Ph) 6.57 (2H, t,
J 5 2.2 Hz, o-H in inner Ph) 6.61 (2H, d, J 5 2.2 Hz, p-H in mid Ph) 6.67
(4H, d, J 5 2.2 Hz, o-H in mid Ph) 7.30–7.43 (20H, m, other Ph) ppm.
[G4]-OH (40). [G3]-Br (5.0 g, 6.19 mmol), 3,5-dihydroxybenzyl alcohol
(522 mg, 5.10 mmol), 18-crown-6-ether (164 mg, 0.62 mmol) and K2CO3
(1.1 g, 8.0 mmol) were suspended in 100 mL of 2-butanone under nitrogen
atmosphere, and the mixture was heated under reflux for 48 h. Conventional
workup and purification by silica-gel column chromatography (eluent
chloroform) yielded 4.5 g of [G4]-OH (91%) as a colorless glass. 1H-NMR
(200 MHz, CDCl3) d 4.55 (2H, d, J 5 6 Hz, Ph––CH2OH) 4.94 (12H, s,
CH2O––Ph) 4.99 (16H, s, CH2O––Ph9) 6.53–6.67 (21H, m, Ph) 7.28–7.41
(40H, m, Ph9) ppm.
[G4]-Br (40). [G4]-OH (4.5 g, 2.83 mmol) was converted to [G4]-Br by
treatment with CBr4 (1.42 g, 4.27 mmol) and triphenylphosphine (1.20 g,
4.53 mmol) in THF (85 mL) for 20 min at room temperature. Conventional
workup and purification by silica-gel column chromatography (eluent:
chloroform–hexane 5 5:1) gave 1.17 g of [G2]-Br (25%) as a colorless glass.
1H-NMR (200 MHz, CDCl3) d 4.36 (2H, s, CH2Br) 4.95 (12H, s, CH2O––Ph)
5.00 (16H, s, CH2O––Ph9) 6.53–6.67 (21H, m, Ph) 7.28–7.41 (40H, m, Ph9).
trans-1. Benzylbromide (674 mg, 3.94 mmol), 3,39,5,59-tetrahydroxy-
Absorption and fluorescence spectra and fluorescence lifetime. Absorp-
tion and fluorescence spectra were measured on a Shimadzu UV-1600 and
on a Hitachi F-4000 fluorescence spectrometer, respectively. Fluorescence
lifetimes were determined with Horiba NAES-1100 time resolved
spectrofluorometer.
Quantum yield of fluorescence emission. Quantum yield of fluorescence
emission were determined by using naphthalene (Uf 5 0.23) (44) and
anthracene (Uf 5 0.27) (44) as standards. A correction of the difference in
refractive index among the solvents was made for each sample. The
absorbance of the sample solution at the excitation wavelength was adjusted
to less than 0.1, and the integration of the fluorescence spectra over wave
number was plotted against absorbance at excitation wavelength. The slope
of these plots gives the relative value of the fluorescence quantum yield,
and the quantum yield of fluorescence emission was determined.
Quantum yield of isomerization. Quantum yield of trans fi cis
isomerization (Utfic) of trans-1 was determined on irradiation at 313 nm
from a 150 W xenon lamp through a monochrometer. The sample solution
was deaerated by bubbling argon and irradiated for 3 min to keep the
conversion within 5%. Light intensity was determined by tris(oxalato)-