Porphyrin Dyads Bearing Carbon Tethers
colorless solid (2.82 g, 40%) with satisfactory characterization data
(mp, H NMR spectrum, and elemental analysis).
was added, and the reaction mixture was filtered through a silica
pad (CH2Cl2). A purple fraction was collected, concentrated, and
chromatographed [silica, CH2Cl2/hexanes (3:1)]. The desired frac-
tion was concentrated. The resulting crude product was suspended
in hexanes and sonicated three times, affording a purple solid (0.159
g, 10%): 1H NMR δ -2.78 (s, 2H), 1.43 (s, 36H), 2.71 (s, 6H),
5.95 (s, 1H), 6.52 (d, J ) 3.6 Hz, 2H), 7.22 (d, J ) 3.6 Hz, 2H),
7.56 (d, J ) 8.0 Hz, 4H), 7.64-7.67 (m, 4H), 7.76-7.79 (m, 3H),
7.81-7.82 (m, 6H), 8.10 (d, J ) 8.0 Hz, 4H), 8.17 (d, J ) 8.0 Hz,
2H), 8.21-8.23 (m, 2H), 8.82-8.87 (m, 8H). LD-MS obsd, 1337.0
[(M + 2t - Bu)+], 1395.1 [(M + 3t - Bu)+, 1451.0 [(M + 4t -
Bu)+; calcd, 1218.6 (M ) C85H82N6O2): λabs 421, 516, 550, 590,
647 nm; λem (λex 550 nm) 654, 722 nm.
1
1,9-Bis(3,5-di-tert-butylbenzoyl)-5-(4-formylphenyl)dipyrro-
methane (12). A general procedure was followed.28 A solution of
11 (18.5 g, 24.0 mmol) in CH2Cl2 (120 mL) was treated with a
solution of TFA (40 mL) and water (20 mL) at room temperature.
The reaction was stopped after 5.5 h. 1H NMR analysis of the crude
reaction mixture upon workup [wash with water and aqueous
NaHCO3, dry (Na2SO4), and concentrate] indicated the complete
removal of the acetal group. The crude product thus obtained was
chromatographed [CH2Cl2/ethyl acetate, 95:5 f 90:10], affording
a brown solid (14.1 g, 86%): mp 167 °C dec; 1H NMR δ 1.27 (s,
36H), 5.84 (s, 1H), 5.95-5.96 (m, 2H), 6.51-6.52 (m, 2H), 7.52-
7.53 (m, 6H), 7.88 (d, J ) 8.0 Hz, 2H), 7.93 (d, J ) 8.0 Hz, 2H),
10.03 (s, 1H), 12.22 (br, 2H); 13C NMR δ 31.3, 34.8, 45.5, 111.2,
121.0, 124.2, 125.6, 129.8, 130.4, 131.3, 135.4, 137.7, 139.9, 148.0,
150.3, 185.6, 191.7. FAB-MS: calcd for C46H54N2O3, 682.4134;
found, 682.4121. Anal. Calcd for C46H54N2O3: C, 80.90; H, 7.97;
N, 4.10. Found: C, 80.28; H, 8.16; N, 4.00.
5-[4-[1,9-Bis(3,5-di-tert-butylbenzoyl)dipyrromethan-5-yl]phen-
yl]dipyrromethane (13). A general procedure with slight modifica-
tion was followed.14 A solution of 12 (14.1 g, 20.6 mmol) in CH2Cl2
(25 mL) and pyrrole (143 mL, 2.06 mol, 100 equiv) was treated
with TFA (159 µL, 2.06 mmol, 0.1 equiv) at room temperature for
10 min. The reaction was quenched with TEA (2 mL), and CH2-
Cl2 was added. The reaction mixture was washed with water, dried
(Na2SO4), and concentrated to obtain a brown oily residue.
Chromatography [silica, hexanes/ethyl acetate (5:1 f 3:1)] afforded
a colorless solid (12.5 g, 75%): mp 174 °C (dec); 1H NMR δ 1.30
(s, 36 H), 5.49 (s, 1H), 5.68 (s, 1H), 5.94-5.95 (m, 2H), 6.02-
6.03 (m, 2H), 6.15-6.17 (m, 2H), 6.59-6.60 (m, 2H), 6.69-6.71
(m, 2H), 7.25-7.26 (m, 2H), 7.49-7.51 (m, 2H), 7.54-7.59 (m,
6H), 7.95 (br, 2H), 11.22 (br, 2H); 13C NMR δ 31.4, 34.8, 43.6,
45.1, 107.2, 108.4, 111.1, 117.2, 120.9, 124.1, 125.4, 128.9, 129.2,
131.2, 132.3, 137.9, 139.7, 141.0, 141.1, 150.2, 185.4. FAB-MS:
calcd for C54H62N4O2, 798.4873; found, 798.4902. Anal. Calcd for
C54H62N4O2: C, 81.16; H, 7.82; N, 7.01. Found: C, 80.73; H, 7.82;
N, 7.01.
Dibutyl[1,9-bis(3,5-di-tert-butylbenzoyl)-5-(4-(dipyrromethan-
5-yl)phenyl)-5,10-dihydrodipyrrinato]tin(IV) (Bu2Sn-13). A
general procedure was followed.21 A mixture of 13 (240 mg, 0.300
mmol), Bu2SnCl2 (91.0 mg, 0.300 mmol), and TEA (83 µL, 0.60
mmol) in CH2Cl2 (3 mL) was stirred at room temperature for 1 h.
The mixture was concentrated. The resulting residue was chro-
matographed [silica, hexanes/ethyl acetate (5:1)], affording a
colorless solid (266 mg, 86%): mp 107 °C (dec); 1H NMR δ 0.70-
0.76 (m, 6H), 1.11-1.25 (m, 4H), 1.32-1.53 (m, 6H), 1.38 (s,
36H), 1.69-1.73 (m, 2H), 5.44 (s, 1H), 5.58 (s, 1H), 5.90 (br, 2H),
6.12-6.15 (m, 2H), 6.19 (d, J ) 4.0 Hz, 2H), 6.67-6.69 (m, 2H),
7.03 (d, J ) 3.6 Hz, 2H), 7.13 (d, J ) 8.0 Hz, 2H), 7.19 (d, J )
8.8 Hz, 2H), 7.61-7.63 (m, 2H), 7.16-7.21 (m, 4H), 7.91 (br,
2H); 13C NMR δ 13.61, 13.66, 24.0, 25.0, 26.02, 26.27, 27.25,
27.29, 31.4, 34.9, 43.5, 45.2, 107.2, 108.3, 115.0, 117.2, 123.2,
123.7, 125.8, 128.32, 128.50, 132.4, 136.1, 137.1, 140.3, 142.9,
150.8, 151.2, 185.6. Anal. Calcd for C62H78N4O2Sn: C, 72.30; H,
7.63; N, 5.44. Found: C, 72.32; H, 7.62; N, 5.50.
5-[4-[1,9-Bis(3,5-di-tert-butylbenzoyl)dipyrromethan-5-yl]phen-
yl]-15-phenyl-10,20-di-p-tolylporphyrin (14). A general procedure
was followed.18,20 A solution of 5 (0.900 g, 1.30 mmol) in THF/
methanol (52 mL, 10:1) was treated with NaBH4 (1.97 g, 52.1
mmol) at room temperature. After 3.5 h, the reaction mixture was
poured in a mixture of saturated aqueous NH4Cl (50 mL) and CH2-
Cl2 (50 mL). The organic phase was isolated, washed with water,
dried (Na2SO4), and concentrated to dryness. A mixture of the
resulting dipyrromethane-dicarbinol and 13 (1.04 g, 1.30 mmol)
was dissolved in CH2Cl2 (520 mL) and stirred until a homogeneous
solution was obtained. Yb(OTf)3 (1.06 g, 1.71 mmol) was added
at room temperature. After 40 min, the reaction mixture was treated
with DDQ (0.885 g, 3.90 mmol) and stirred for 1 h. TEA (3 mL)
5-Phenyl-10,20-di-p-tolyl-15-[4-(2-(trimethylsilyl)ethynyl)-
phenyl]porphyrin (15). A general procedure was followed.18,20
A
solution of 5 (1.40 g, 2.03 mmol) in THF/methanol (81 mL, 10:1)
was treated with NaBH4 (3.07 g, 81.2 mmol) at room temperature.
After 3.5 h, the reaction mixture was poured in a mixture of
saturated aqueous NH4Cl (100 mL) and CH2Cl2 (100 mL). The
organic phase was isolated, washed with water, dried (Na2SO4),
and concentrated to dryness. A mixture of the resulting dipyr-
romethane-dicarbinol and 1d (0.645 g, 2.03 mmol) was dissolved
in CH2Cl2 (812 mL) and stirred until a homogeneous solution was
obtained. Yb(OTf)3 (1.61 g, 2.60 mmol) was added at room
temperature. After 40 min, the reaction mixture was treated with
DDQ (1.38 g, 6.08 mmol) and stirred for 1 h. Then TEA (3 mL)
was added, and the reaction mixture was filtered through a silica
pad (CH2Cl2). The purple band was collected, concentrated, and
chromatographed [silica, CH2Cl2/hexanes (3:1)]. The desired frac-
tion was concentrated. The crude product was suspended in
methanol and sonicated three times, affording a purple solid (0.430
g, 29%): 1H NMR δ -2.79 (s, 2H), 0.39 (s, 9H), 2.72 (s, 6H),
7.57 (d, J ) 7.6 Hz, 4H), 7.76-7.78 (m, 3H), 7.88 (d, J ) 8.0 Hz,
2H), 8.10 (d, J ) 7.6 Hz, 4H), 8.17 (d, J ) 8.0 Hz, 2H), 8.22 (d,
J ) 6.4 Hz, 2H), 8.80-8.88 (m, 8H). LD-MS obsd, 738.4. FAB-
MS obsd, 739.3253; calcd, 739.3257 [(M + H)+; M ) C51H42N4Si]:
λabs 421, 516, 550, 596, 649 nm; λem (λex 550 nm) 655, 722 nm.
5-(4-Ethynylphenyl)-15-phenyl-10,20-di-p-tolylporphyrin (16).
A solution of 15 (0.150 g, 0.203 mmol) in CHCl3/THF (23 mL,
3:1) was treated with TBAF (0.305 mL, 0.31 mmol, 1.0 M in THF)
at room temperature. After 1 h, TLC analysis [CH2Cl2/hexanes (3:
1)] showed the complete consumption of 15. The reaction mixture
was diluted with CH2Cl2 and then washed with 10% aqueous
NaHCO3 and water. The organic layer was dried (Na2SO4),
concentrated, and chromatographed [silica, CH2Cl2/hexanes (3:1)].
The solid product was suspended in methanol and sonicated three
times, affording a purple solid (0.131 g, 96%): 1H NMR δ -2.78
(s, 2H), 2.72 (s, 6H), 3.34 (s, 1H), 7.57 (d, J ) 7.2 Hz, 4H), 7.75-
7.82 (m, 3H), 7.91 (d, J ) 8.0 Hz, 2H), 8.11 (d, J ) 7.2 Hz, 4H),
8.19-8.24 (m, 4H), 8.82-8.90 (m, 8H). LD-MS obsd, 666.5. FAB-
MS obsd, 667.2885; calcd, 667.2862 [(M + H)+; M ) C48H34N4]:
λabs 421, 516, 550, 596, 649 nm; λem (λex 550 nm) 654, 721 nm.
5-[4-(1,1-Diallyl-3-buten-1-yl)phenyl]-10,20-bis(3,5-di-tert-bu-
tyl)-15-(4-iodophenyl)porphyrin (18). A general procedure was
followed.18,20 A solution of 17 (0.350 g, 0.448 mmol) in THF/
methanol (18 mL, 10:1) was reacted with NaBH4 (0.339 g, 8.97
mmol) at room temperature for 40 min. The reaction mixture was
poured in a mixture of saturated aqueous NH4Cl (20 mL) and CH2-
Cl2 (20 mL). The organic phase was isolated, washed with water,
dried (Na2SO4), and concentrated to dryness. The resulting dipyr-
romethane-dicarbinol and 1c (0.160 g, 0.449 mmol) were dissolved
in CH2Cl2 (180 mL) and then treated with Yb(OTf)3 (0.357 g, 0.576
mmol) at room temperature. After 40 min, DDQ (0.306 g, 1.35
mmol) was added, and the mixture was stirred for 1 h. The reaction
mixture was neutralized with TEA (2 mL) and filtered through a
silica pad (CH2Cl2). The purple band was collected, concentrated,
and chromatographed [silica, CH2Cl2/hexanes (3:1)]. The crude
product was suspended in methanol and sonicated three times,
affording a purple solid (0.161 g, 33%): 1H NMR δ -2.74 (s, 2H),
J. Org. Chem, Vol. 71, No. 3, 2006 1169