A R T I C L E S
Satoh et al.
calcd 1257.63. Anal. Calcd for C87H60N4S3: C, 83.09; H, 4.81; N, 4.45;
S, 7.65. Found: C, 82.53; H, 5.18; N, 4.28; S, 7.72.
119.85; IR (KBr, cm-1) 1614 (CdN), 1577 (phenyl), 847, 785, 695;
MS (MALDI-TOF) m/z 8782.7 (M+), calcd 8784.76. Anal. Calcd for
Synthesis of TPA-DPA G2. To a mixture of TPA-NH2 (3, 76 mg,
100 µmol), DPA dendron G2 (216 mg, 400 µmol), DABCO (134.6
mg, 1.2 mmol), and chlorobenzene (16 mL) warmed at 80 °C was added
titanium(IV) chloride (60 µL, 0.5 mmol) under a nitrogen atmosphere.
The reaction mixture was warmed to 125 °C and stirred overnight.
The precipitate was then filtered off, the filtrate was evaporated, and
the residue was purified by column chromatography on silica gel using
a mixture of hexane, dichloromethane, and ethyl acetate (6:6:1, v/v).
Preparative SEC then gave TPA-DPA G2 as a yellow powder (173
C633H438N46S3: C, 86.55; H, 5.03; N, 7.33; S, 1.10. Found: C, 86.06;
H, 5.48; N, 7.08; S, 1.19.
Synthesis of TPA-DPA G5. To a mixture of TPA-NH2 (3, 38 mg,
50 µmol), DPA dendron G5 (1.11 g, 200 µmol), DABCO (134.6 mg,
1.2 mmol), and chlorobenzene (100 mL) warmed at 80 °C was added
titanium(IV) chloride (60 µL, 0.5 mmol) under a nitrogen atmosphere.
The reaction mixture was warmed to 125 °C and stirred overnight.
The precipitate was then filtered off, the filtrate was evaporated, and
the residue was purified by preparative SEC to give TPA-DPA G5 as
1
1
mg, 74%); H NMR (400 MHz, CDCl3, 24 °C, TMS) δ ) 7.75 (d, J
a yellow powder (98 mg, 11%); H NMR (400 MHz, CDCl3, 25 °C,
) 8.4 Hz, 6H), 7.71 (d, J ) 6.8 Hz, 6H), 7.54-7.50 (m, 12H), 7.47-
7.35 (m, 24H), 7.27 (m, 6H), 7.23-7.14 (m, 30H), 7.01 (m, 6H), 6.87
(d, J ) 8.4 Hz, 6H), 6.73 (d, J ) 8.4 Hz, 6H), 6.63 (d, J ) 8.8 Hz),
6.58 (d, J ) 8.4 Hz, 6H); 13C NMR (100 MHz, CDCl3, 25 °C, TMS)
δ ) 168.72, 168.25, 167.88, 153.52, 151.61, 150.82, 146.16, 143.12,
142.088, 139.19, 139.00, 135.75, 135.56, 134.36, 130.83, 130.77,
129.93, 129.90, 129.54, 129.28, 129.24, 129.20, 128.77, 128.70, 128.52,
128.06, 127.92, 127.70, 126.30, 125.42, 124.30, 123.24, 122.90, 121.76,
120.44, 120.22; IR (KBr, cm-1): 1615 (CdN), 1590 (phenyl), 843,
798, 697; MS (MALDI-TOF) m/z 2332.4 (M+), calcd 2332.94; Anal.
Calcd for C165H114N10S3: C, 84.95; H, 4.93; N, 6.00; S, 4.12. Found:
C, 84.39; H, 5.04; N, 5.75; S, 4.29.
Synthesis of TPA-DPA G3. To a mixture of TPA-NH2 (3, 76 mg,
100 µmol), DPA dendron G3 (503 mg, 400 µmol), DABCO (134.6
mg, 1.2 mmol), and chlorobenzene (16 mL) warmed at 80 °C was added
titanium(IV) chloride (60 µL, 0.5 mmol) under a nitrogen atmosphere.
The reaction mixture was warmed to 125 °C and stirred overnight.
The precipitate was then filtered off, the filtrate was evaporated, and
the residue was purified by column chromatography on silica gel using
a mixture of hexane, dichloromethane, and ethyl acetate (5:5:1, v/v).
Preparative SEC then gave TPA-DPA G3 as a yellow powder (309
mg, 69%); 1H NMR (400 MHz, CDCl3, 24 °C, TMS) δ ) 7.74-7.71
(m, 24H), 7.55-6.52 (m, 198H); 13C NMR (100 MHz, CDCl3, 25 °C,
TMS) δ ) 168.74, 168.55, 168.25, 168.21, 168.012, 167.95, 167.73,
153.95, 153.62, 153.53, 151.95, 151.75, 139.10, 138.96, 138.83, 135.67,
135.60, 135.49, 134.23, 134.10, 133.86, 130.78, 130.52, 130.21, 130.04,
129.95, 129.25, 128.89, 128.67, 128.50, 128.05, 127.89, 127.70, 127.60,
127.34, 126.22, 125.47, 125.37, 124.19, 123.20, 123.07, 121.99, 121.72,
120.74, 120.39, 120.19, 119.84; IR (KBr, cm-1) 1617 (CdN), 1582
(phenyl), 836, 797, 693; MS (MALDI-TOF) m/z 4483.1 (M+), calcd
4483.54. Anal. Calcd for C321H222N22S3: C, 85.99; H, 4.99; N, 6.87;
S, 2.15. Found: C, 85.53; H, 5.14; N, 6.63; S, 2.16.
TMS) δ ) 7.75-6.73 (m, 870H); 13C NMR (100 MHz, CDCl3, 25 °C,
TMS) δ ) 168.81, 168.55, 168.27, 168.00, 167.83, 167.69, 154.03,
153.61, 152.53, 151.77, 139.17, 138.95, 138.64, 135.66, 135.46, 134.12,
130.80, 130.47, 129.99, 129.27, 128.72, 128.08, 127.92, 127.78, 120.76,
120.41, 120.19, 119.91; IR (KBr, cm-1) 1614 (CdN), 1577 (phenyl),
847, 785, 695; MS (MALDI-TOF) m/z 17393.3 (M+), calcd 17387.18.
Anal. Calcd for C1257H870N94S3: C, 86.83; H, 5.04; N, 7.57. Found:
C, 86.06; H, 5.48; N, 7.08.
Preparation of the Photoelectrode. TiO2 paste (Ti-Nanoxide D)
was deposited onto a glass sheet coated with a fluorine-doped stannic
oxide layer (sheet resistance, 10 Ω/cm2) using a “squeegee” technique.
The heated electrodes were impregnated with a 0.05 M titanium(IV)
chloride solution in a water-saturated desiccator for 30 min at 70 °C,
washed with distilled water, and heated for 10 min at 450 °C in air.
The hot electrodes were allowed to cool to 100 °C and then immediately
soaked in a mixture solution of acetonitrile/1-propanol (1:1, v/v)
containing cis-bis(isothiocyanato)bis(2,2′ bipyridyl-4,4′-dicarboxylato)-
ruthenium(II) bis-tetrabutylammonium (N719) dye. The concentration
of this solution was maintained at a minimum of 3 × 10-4 M.2a
Fabrication of the DSSC. The DSSC was fabricated in air as a
sandwich-type open electrochemical cell composed of a dye-adsorbed
TiO2 electrode, a spacer, and a Pt counter electrode. The electrolyte
solution for analysis was composed of 0.6 M dimethylpropylimidazo-
lium iodide (DMP II), 0.05 M iodine, and 0.1 M lithium iodide in
3-methoxypropionitrile (MPN). The dye-coated semiconductor film was
illuminated through a conducting glass support with a mask.
Acknowledgment. The authors extend their gratitude to Dr.
H. Arakawa and Dr. T. Yamaguchi for useful suggestions on
DSSC fabrication and to Mr. M. Minoda for support in DSSC
measurements. And we also thank Dr. J-S. Cho and Dr. M.
Higuchi for their suggestions on our work. This work was
supported in part by the Core Research for Evolutional Science
and Technology (CREST) program of the Japan Science and
Technology (JST) Agency, by a Grant-in-Aid for Scientific
Research (No. 15350073) offered under the 21st Century Center
of Excellence (COE) program (Keio-LCC) of the Ministry of
Education, Culture, Sports, Science and Technology (MEXT)
of Japan, and by a research grant (Project No. 23) from the
Kanagawa Academy of Science and Technology (KAST).
Synthesis of TPA-DPA G4. To a mixture of TPA-NH2 (3, 76 mg,
100 µmol), DPA dendron G4 (1.07 g, 400 µmol), DABCO (134.6 mg,
1.2 mmol), and chlorobenzene (16 mL) warmed at 80 °C was added
titanium(IV) chloride (60 µL, 0.5 mmol) under a nitrogen atmosphere.
The reaction mixture was warmed to 125 °C and stirred overnight.
The precipitate was then filtered off, the filtrate was evaporated, and
the residue was purified by preparative SEC to give TPA-DPA G4 as
1
a yellow powder (591 mg, 67%); H NMR (400 MHz, CDCl3, 25 °C,
TMS) δ ) 7.75-6.73 (m, 438H); 13C NMR (100 MHz, CDCl3, 25 °C,
TMS) δ ) 168.79, 168.60, 168.31, 168.17, 168.03, 167.84, 155.01,
153.62, 152.03, 151.75, 139.14, 138.92, 138.63, 135.69, 135.51, 135.32,
134.32, 134.06, 133.84, 130.77, 130.47, 130.24, 129.96, 129.62, 129.36,
129.25, 128.69, 128.43, 128.06, 127.90, 127.72, 126.18, 125.45, 124.16,
123.42, 123.05, 122.18, 121.98, 120.95, 120.74, 120.39, 120.16, 119.92,
Supporting Information Available: Additional data provided
in PDF file. This material is available free of charge via the
JA050765C
9
13038 J. AM. CHEM. SOC. VOL. 127, NO. 37, 2005