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Synlett 2002(3): 0415-0418
DOI: 10.1055/s-2002-20454
LETTER
© Georg Thieme Verlag Stuttgart · New York

Sandwich Dimer Complexes of Zinc Porphyrins Bearing Three-Dimensionally Oriented Redox-Active π-Conjugated Pendant Groups

Toshikazu Hirao*, Kaori Saito
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Yamada-oka, Suita, Osaka 565-0871, Japan
Fax: +81(6)68797415; e-Mail: hirao@ap.chem.eng.osaka-u.ac.jp;
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Publication History

Received 12 November 2001
Publication Date:
05 February 2007 (online)

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Abstract

Treatment of the zinc porphyrins bearing four dimensionally oriented phenylenediamine strands with a bidentate ligand, DABCO, led to the formation of the sandwich dimer complexes, in which the porphyrin moieties are surrounded by π-conjugated pendant groups.

Key words

zinc porphyrin - π-conjugated pendant group - dimensional control - diazabicyclooctane (DABCO) - sandwich dimer complex

7

EDCI·HCl (22.3 mg, 0.117 mmol) and HOBt (59.4 mg, 0.117 mmol) were added to a THF solution (10 mL) of 1 (21.6 mg, 0.0194 mmol) at room temperature and the solution was stirred for 30 min. Then, a THF solution (15 mL) of N-phenyl-1,4-phenylenediamine (21.5 mg, 0.117 mmol) was added to the reaction mixture, which was stirred for 24 h and then evaporated. Purification by column chromatography on silica gel using solvents with gradient from dichloromethane to dichloromethane-ethyl acetate (8:2 v/v) and recrystallization from THF-methanol gave 2a in 68% yield.

8

A THF solution (5 mL) of 2a (20.0 mg, 11 µmol) was added to a methanol solution of zinc(II) acetate dihydrate (10.3 mg, 55 µmol), which refluxed under argon for 12 h and then evaporated. Purification by column chromatography on alumina (acetone-methanol 95:5 v/v) gave 3a in 90% yield. 3a: pinkish light brown solid; mp 223-225 °C(uncorrected); Rf = 0.60 (SiO2, ethyl acetate); IR (KBr) 3380, 3051, 1678, 1593, 1511, 1496, 1323, 1271, 1109, 799 cm-1; 1H NMR (600 MHz, CD2Cl2) δ 8.71 (br s, 8 H), 8.28 (d, 4 H, J = 9.2 Hz), 8.12 (d, 4 H, J = 8.5 Hz), 7.45 (dd, 4 H, J = 8.5, 6.6 Hz), 7.41 (d, 4 H, J = 8.7 Hz), 7.35 (d, 4 H, J = 9.2 Hz), 7.23 (dd, 4 H, J = 8.7, 6.6 Hz), 7.13 (dd, 8 H, J = 8.2, 7.3 Hz), 6.80 (t, 4 H, J = 7.3 Hz), 6.64 (d, 8 H, J = 8.2 Hz), 5.71 (br s, 4 H), 5.67-5.60 (br, 8 H), 5.28 (bs, 4 H), 5.24-5.12 (br, 8 H), 3.60 (br s, 8 H); MS (FAB) m/z 1838.8 (M + 2H)+; UV-vis(dichloromethane) λmax (log ε) 549 (4.34), 430 (5.45), 303 (4.95); Anal. Calcd. for C116H84N12O8Zn·H2O: C, 75.01; H, 4.67; N, 9.05. Found: C, 74.90; H, 4.78; N, 8.91.

9

The reason for the upper shift of H b , H c , and H d remains obscure, but it may be due to the shield effect of the naphthalene rings.

10

4a: purple solid; mp 235-238 °C(uncorrected); IR (KBr) 3379, 3051, 1679, 1594, 1511, 1495, 1322, 1269, 1229, 1108, 1063, 798 cm-1; 1H NMR: See Table; MS (TOF) m/z 1841.3 [M- 3a -112(DABCO) + 2]+.

12

Purification of 2b was performed by column chromatography on silica gel eluting with ethyl acetate and further reprecipitation from ether to give 2b in 68% yield. 2b: brown solid; mp 204-206 °C(uncorrected); Rf = 0.45 (SiO2, ethyl acetate); IR (KBr) 3380, 3321, 3044, 1675, 1598, 1505, 1494, 1302, 1108, 802 cm-1; 1H NMR (600 MHz, DMSO-d 6) δ 8.56 (bs, 8 H), 8.33 (d, 4 H, J = 9.3 Hz), 8.11 (d, 4 H, J = 8.4 Hz), 7.87 (bs, 4 H), 7.75 (bs, 4 H), 7.65 (d, 4 H, J = 9.3 Hz), 7.48 (bs, 4 H), 7.38 (dd, 4 H, J = 8.4, 6.8 Hz), 7.16-7.10 (m, 12 H), 6.94-6.89 (m, 20 H), 6.77 (d, 8 H, J = 8.5 Hz), 6.68 (t, 4 H, J = 7.3 Hz), 6.20-6.10 (br, 16 H), 4.21 (bs, 8 H), -2.04 (bs, 2 H); MS (TOF) m/z 2141.9 (M + H)+; UV-vis (CHCl3) λmax (log ε) 645 (3.32), 590 (3.74), 547 (3.54), 517 (4.23), 428 (5.29), 317 (5.03); Anal. Calcd. for C140H106N16O8·2H2O: C, 77.26; H, 5.09; N, 10.30. Found: C, 77.39; H, 4.96; N,10.16.

13

3b: pinkish light brown solid; mp 214-216 °C(uncorrected); Rf = 0.20 (SiO2, ethyl acetate); IR (KBr) 3377, 3046, 1678, 1598, 1510, 1496, 1304, 1271, 1109, 801 cm-1; 1H NMR (600 MHz, CDCl3) δ 8.67 (bs, 8 H), 8.19 (d, 4 H, J = 9.3 Hz), 8.03 (d, 4 H, J = 8.5 Hz), 7.41 (dd, 4 H, J = 8.5, 6.6 Hz), 7.37 (d, 4 H, J = 8.9 Hz), 7.32 (d, 4 H, J = 9.3 Hz), 7.20 (dd, 4 H, J = 8.9, 6.6 Hz), 7.16 (dd, 8 H, J = 8.3, 7.3 Hz), 6.92-6.79 (m, 16 H), 6.83 (t, 4 H, J = 7.3 Hz), 6.58 (d, 8 H, J = 8.3 Hz), 5.71 (bs, 4 H), 5.60-5.51 (br, 8 H), 5.43 (bs, 4 H), 5.25-5.15 (br, 8 H), 5.06 (bs, 4 H), 3.66 (bs, 8 H); MS (TOF) m/z 2205.1 (M + H)+; UV-vis (CHCl3) λmax (log ε) 549 (4.25), 429 (5.38), 315 (4.99); Anal. Calcd. for C140H104N16O8Zn: C, 76.30; H, 4.76; N, 10.17. Found: C, 76.29; H, 4.93; N, 10.13.

14

4b: purple solid; mp >300 °C; IR (KBr) 3377, 3031, 1684, 1596, 1508, 1464, 1320, 1298, 1252, 1212, 1109, 1070, 798 cm-1; 1H NMR: See Table; MS (TOF) m/z 2205.7 [M - 3b - 112(DABCO) + 2H]+.