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S. PISANO ET AL.
70.9, 70.8, 70.0, 67.9, 59.2. MS (ESI): m/z 963 (calcd.
b-H), 8.84 (4H, d, J = 5.0 Hz, b-H), 8.17 (4H, dd, J = 6.0,
2.0 Hz, Hb-Py), 8.13 (4H, d, J = 8.0 Hz, Ha-PhI), 7.95
(4H, d, J = 8.0 Hz, Hb-PhI), -2.89 (2H, br, NH). 13C NMR
(125 MHz; CDCl3): dC, ppm 150.0, 148.3, 141.1, 136.1,
136.0, 129.3, 119.5, 117.3, 94.5. MS (ESI): m/z 869
(calcd. for [C42H26I2N6 + H]+ 869.04). UV-vis (CH2Cl2):
for [C56H56N6O8 + Na]+ 963.40). UV-vis (CH2Cl2): lmax
,
nm (relative intensity, %) 419 (100), 516 (5.2), 550 (3.0),
592 (1.9), 651 (2.7). Fluorescence emission (CH2Cl2, lexc
426 nm): lem, nm 655, 719. IR (KBr): n, cm-1 3078, 2922,
2860, 1637, 1593, 1449, 1404, 1384, 1351, 1286, 1246,
1175, 1108, 967, 788, 737.
l
max, nm (relative intensity, %) 418 (100), 514 (4.3),
Porphyrins 3a–3b. The reaction was conducted
under Ar atmosphere and in the dark. 5-(4-pyridyl)
dipyrromethane (594 mg, MW = 223.27, 2.66 mmol) and
4-iodobenzaldehyde (309 mg, MW = 232.02, 1.33 mmol)
were dissolved in anhydrous DCM (270 mL). A solution
of TegPhCHO (381 mg, MW = 268.306, 1.33 mmol) in
30 mL of anhydrous DCM was added and the mixture
was cooled to 0°C with an ice bath. Then NEt3 (6.12 mL,
d = 1.535 g/mL, 82.5 mmol) was added dropwise and the
reaction was kept under stirring for 1.5 h. The reaction
mixture was let to reach room temperature and with no
more inert atmosphere DDQ (1.21 g, 5.32 mmol) was
added and the reaction was stirred for further 2 h. The
crude mixture was directly washed three times with a
saturated solution of NaHCO3 and once with water. The
organic phase was dried over Na2SO4 and the solvent
was removed under reduced pressure. The residue was
purified by CC on silica gel (CHCl3/EtOH from 100/0 to
97/3 v/v). The fractions containing the three porphyrins
were further purified by another CC on silica gel (CHCl3/
EtOH from 100/0 to 98/2). Each product was then
obtained as a violet solid by precipitation from CHCl3/
MeOH.Yield: 3a 17%, 3b 8.0%, 2c 5%. Total porphyrins
yield 30%.
5,15-bis-(4-pyridyl)-10-(4-iodophenyl)-20-(4-[2-[2-
(2-methoxyethoxy)ethoxy]ethoxy]phenyl)porphyrin
(3a). Rf = 0.49 (SiO2, CHCl3/MeOH 97/3 v/v). 1H NMR
(500 MHz; CDCl3): dH, ppm 9.06 (4H, d, J = 5.5 Hz,
Ha-Py), 8.95 (2H, d, J = 5.0 Hz, b-H), 8.89 (2H, d, J =
4.5 Hz, b-H), 8.82 (4H, m, b-H), 8.18 (4H, d, J = 5.5 Hz,
Hb-Py), 8.12 (4H, s, H1-Ph and Ha-PhI), 7.95 (4H, d,
J = 8.0 Hz, Hb-Ph), 7.33 (4H, d, J = 9.0 Hz, H2-Ph), 4.45
(2H, m, PhOCH2CH2O), 4.08 (2H, m, OCH2CH2O), 3.90
(2H, m, OCH2CH2O), 3.81 (2H, m, OCH2CH2O), 3.76
(2H, m, OCH2CH2O), 3.64 (2H, m, OCH2CH2OCH3),
3.44 (3H, s, OCH3), -2.85 (2H, br, NH). 13C NMR (125
MHz; CDCl3): dC, ppm 158.9, 150.2, 148.3, 141.3, 136.1,
136.0, 135.6, 134.1, 129.4, 121.2, 119.1, 117.1, 113.0,
94.4, 72.0, 71.0, 70.8, 70.7, 70.0, 67.8, 59.2. MS (ESI):
m/z 905, 927 (calcd. for [C49H41IN6O4 + H]+ 905.23,
[C49H41IN6O4 + Na]+ 927.21). UV-vis spectrum (CH2Cl2):
548 (1.5), 590 (1.1), 650 (1.0). Fluorescence emission
(CH2Cl2, lexc 420 nm): lem, nm 656, 716. IR (KBr): n,
cm-1 2921, 1637, 1591, 14783, 1384, 967, 796, 783, 725.
Synthesis of porphyrin dimers 1a–1c
Dimer 1a. Anhydrous THF, anhydrous DMF and
NEt3 were degassed for 1 h with Ar. A solution of 2a
(21 mg, MW = 802.9, 0.026 mmol) in 1 mL of anhydrous
THF was prepared and kept under Ar atmosphere.
Porphyrin 3a (21.7 mg, MW = 904.79, 0.024 mmol) was
placed in the microwave reactor vessel and set under inert
atmosphere. Then DMF (1.2 mL) and NEt3 (0.8 mL) were
added and the mixture was degassed for 15 min with
Ar. Lastly, keeping the vessel under inert atmosphere,
Pd(PPh3)4 (1.4 mg, MW = 1154.56, 0.0012 mmol)
was added and the mixture was degassed for further
15 min. Keeping the vessel under Ar, the solution of 2a
was added. The reaction was stirred for 1 h at 120°C
under microwave irradiation (ramping time = 10 min,
P = 300 W). The crude mixture was passed through a
very short Celite® 521 pad washing with CHCl3/MeOH
9/1. The organic solvent was then extracted twice with
distilled water to remove the DMF, dried with Na2SO4 and
finally the solvent was removed under reduced pressure.
Purification of the crude by CC (CHCl3/EtOH from
98/2 to 97:3 v/v) afforded a purple solid. Yield 9.1 mg
(24%). Rf = 0.43 (SiO2, CHCl3/MeOH 95/5 v/v). 1H NMR
(500 MHz, CDCl3): dH, ppm 9.08 (8H, d, J = 5.5 Hz,
Ha-Py), 9.00 (4H, d, J = 4.5 Hz, b-H), 8.97 (4H, d,
J = 4.5 Hz, b-H), 8.89 (4H, d, J = 5.0 Hz, b-H), 8.84
(4H, d, J = 5.0 Hz, b-H), 8.31 (4H, d, J = 8.0 Hz, H4-Ph),
8.21 (8H, dd, J = 6.0, 3.0 Hz, Hb-Py), 8.14–8.11 (8H, m,
H1-Ph and H3-Ph), 7.35 (4H, d, J = 8.5 Hz, H2-Ph), 4.46
(4H, m, PhOCH2CH2O), 4.09 (4H, m, OCH2CH2O),
3.91 (4H, m, OCH2CH2O), 3.82 (4H, m, OCH2CH2O),
3.77 (4H, m, OCH2CH2O), 3.65 (4H, m, OCH2CH2O),
3.44 (6H, s, OCH3), -2.80 (4H, br, NH). 13C NMR (125
MHz, CDCl3): dC, ppm 159.3, 150.6, 148.7, 142.4, 135.9,
135.0, 134.4, 130.6, 130.1, 129.8, 123.4, 121.5, 120.1,
117.5, 113.4, 91.0, 72.4, 71.3, 71.2, 71.0, 70.3, 68.1,
59.5. MS (ESI): m/z 1577 (calcd. for [C100H82N12O8 – H]−
1577.63). UV-vis (CH2Cl2): lmax, nm (relative intensity,
%) 423 (100), 516 (5.2), 551 (2.5), 591 (1.2), 649 (0.9).
Fluorescence emission (CH2Cl2, lexc 420 nm): lem, nm
654, 718. IR (KBr): n, cm-1 2919, 1853, 2361, 1719,
1637, 1592, 1473, 1384, 1282, 1247, 1106, 1072, 968,
800, 732.
l
max, nm (relative intensity, %) 419 (100), 515 (4.8),
550 (2.2), 591 (1.5), 651 (1.8). Fluorescence emission
(CH2Cl2, lexc 420 nm): lem, nm 655, 717. IR (KBr): n,
cm-1 2922, 2853, 1636, 1593, 1472, 1384, 1283, 1248,
1105, 968, 799, 732.
5,15-bis-(4-pyridyl)-10,20-bis-(4-iodophenyl)
porphyrin (3b) [17]. Rf = 0.67 (SiO2, CHCl3/MeOH
1
97/3 v/v). H NMR (500 MHz; CDCl3): dH, ppm 9.07
Dimer 1b. CuCl (5.3 mg, 0.0054 mmol) was inserted
in a round bottom flask and TMEDA (24.0 mL, d = 0.78,
(4H, dd, J = 5.5, 1.5 Hz, Ha-Py), 8.90 (4H, d, J = 4.5 Hz,
Copyright © 2016 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2016; 20: 522–524